****************************************************************************/
/*!
- \example widgets/widgets/analogclock
+ \example widgets/analogclock
\title Analog Clock Example
The Analog Clock example shows how to draw the contents of a custom
We subclass \l QWidget and reimplement the standard
\l{QWidget::paintEvent()}{paintEvent()} function to draw the clock face:
- \snippet widgets/widgets/analogclock/analogclock.h 0
+ \snippet widgets/analogclock/analogclock.h 0
\section1 AnalogClock Class Implementation
- \snippet widgets/widgets/analogclock/analogclock.cpp 1
+ \snippet widgets/analogclock/analogclock.cpp 1
When the widget is constructed, we set up a one-second timer to
keep track of the current time, and we connect it to the standard
Finally, we resize the widget so that it is displayed at a
reasonable size.
- \snippet widgets/widgets/analogclock/analogclock.cpp 8
- \snippet widgets/widgets/analogclock/analogclock.cpp 10
+ \snippet widgets/analogclock/analogclock.cpp 8
+ \snippet widgets/analogclock/analogclock.cpp 10
The \c paintEvent() function is called whenever the widget's
contents need to be updated. This happens when the widget is
can fit the clock face inside the widget. It is also useful to determine
the current time before we start drawing.
- \snippet widgets/widgets/analogclock/analogclock.cpp 11
- \snippet widgets/widgets/analogclock/analogclock.cpp 12
- \snippet widgets/widgets/analogclock/analogclock.cpp 13
- \snippet widgets/widgets/analogclock/analogclock.cpp 14
+ \snippet widgets/analogclock/analogclock.cpp 11
+ \snippet widgets/analogclock/analogclock.cpp 12
+ \snippet widgets/analogclock/analogclock.cpp 13
+ \snippet widgets/analogclock/analogclock.cpp 14
The contents of custom widgets are drawn with a QPainter.
Painters can be used to draw on any QPaintDevice, but they are
hour and minute. This means that the hand will be shown rotated clockwise
by the required amount.
- \snippet widgets/widgets/analogclock/analogclock.cpp 15
- \snippet widgets/widgets/analogclock/analogclock.cpp 16
+ \snippet widgets/analogclock/analogclock.cpp 15
+ \snippet widgets/analogclock/analogclock.cpp 16
We set the pen to be Qt::NoPen because we don't want any outline,
and we use a solid brush with the color appropriate for
displaying hours. Brushes are used when filling in polygons and
other geometric shapes.
- \snippet widgets/widgets/analogclock/analogclock.cpp 17
- \snippet widgets/widgets/analogclock/analogclock.cpp 19
+ \snippet widgets/analogclock/analogclock.cpp 17
+ \snippet widgets/analogclock/analogclock.cpp 19
We save and restore the transformation matrix before and after the
rotation because we want to place the minute hand without having to
take into account any previous rotations.
- \snippet widgets/widgets/analogclock/analogclock.cpp 20
+ \snippet widgets/analogclock/analogclock.cpp 20
\codeline
- \snippet widgets/widgets/analogclock/analogclock.cpp 21
+ \snippet widgets/analogclock/analogclock.cpp 21
We draw markers around the edge of the clock for each hour. We
draw each marker then rotate the coordinate system so that the
painter is ready for the next one.
- \snippet widgets/widgets/analogclock/analogclock.cpp 22
- \snippet widgets/widgets/analogclock/analogclock.cpp 23
+ \snippet widgets/analogclock/analogclock.cpp 22
+ \snippet widgets/analogclock/analogclock.cpp 23
The minute hand is rotated in a similar way to the hour hand.
- \snippet widgets/widgets/analogclock/analogclock.cpp 25
+ \snippet widgets/analogclock/analogclock.cpp 25
\codeline
- \snippet widgets/widgets/analogclock/analogclock.cpp 26
+ \snippet widgets/analogclock/analogclock.cpp 26
Again, we draw markers around the edge of the clock, but this
time to indicate minutes. We skip multiples of 5 to avoid drawing
****************************************************************************/
/*!
- \example widgets/widgets/calculator
+ \example widgets/calculator
\title Calculator Example
The example shows how to use signals and slots to implement the
\section1 Calculator Class Definition
- \snippet widgets/widgets/calculator/calculator.h 0
+ \snippet widgets/calculator/calculator.h 0
The \c Calculator class provides a simple calculator widget. It
inherits from QDialog and has several private slots associated
multiplicative operators (\uicontrol{\unicode{215}}, \uicontrol{\unicode{247}}). The other buttons
have their own slots.
- \snippet widgets/widgets/calculator/calculator.h 1
- \snippet widgets/widgets/calculator/calculator.h 2
+ \snippet widgets/calculator/calculator.h 1
+ \snippet widgets/calculator/calculator.h 2
The private \c createButton() function is used as part of the
widget construction. \c abortOperation() is called whenever a
applied to a negative number. \c calculate() applies a binary
operator (\uicontrol{+}, \uicontrol{-}, \uicontrol{\unicode{215}}, or \uicontrol{\unicode{247}}).
- \snippet widgets/widgets/calculator/calculator.h 3
- \snippet widgets/widgets/calculator/calculator.h 4
- \snippet widgets/widgets/calculator/calculator.h 5
- \snippet widgets/widgets/calculator/calculator.h 6
- \snippet widgets/widgets/calculator/calculator.h 7
- \snippet widgets/widgets/calculator/calculator.h 8
+ \snippet widgets/calculator/calculator.h 3
+ \snippet widgets/calculator/calculator.h 4
+ \snippet widgets/calculator/calculator.h 5
+ \snippet widgets/calculator/calculator.h 6
+ \snippet widgets/calculator/calculator.h 7
+ \snippet widgets/calculator/calculator.h 8
These variables, together with the contents of the calculator
display (a QLineEdit), encode the state of the calculator:
they can be applied immediately since the operand is already
known when the operator button is clicked.
- \snippet widgets/widgets/calculator/calculator.h 9
+ \snippet widgets/calculator/calculator.h 9
\codeline
- \snippet widgets/widgets/calculator/calculator.h 10
+ \snippet widgets/calculator/calculator.h 10
Finally, we declare the variables associated with the display and the
buttons used to display numerals.
\section1 Calculator Class Implementation
- \snippet widgets/widgets/calculator/calculator.cpp 0
+ \snippet widgets/calculator/calculator.cpp 0
In the constructor, we initialize the calculator's state. The \c
pendingAdditiveOperator and \c pendingMultiplicativeOperator
variables don't need to be initialized explicitly, because the
QString constructor initializes them to empty strings.
- \snippet widgets/widgets/calculator/calculator.cpp 1
- \snippet widgets/widgets/calculator/calculator.cpp 2
+ \snippet widgets/calculator/calculator.cpp 1
+ \snippet widgets/calculator/calculator.cpp 2
We create the QLineEdit representing the calculator's display and
set up some of its properties. In particular, we set it to be
We also enlarge \c{display}'s font by 8 points.
- \snippet widgets/widgets/calculator/calculator.cpp 4
+ \snippet widgets/calculator/calculator.cpp 4
For each button, we call the private \c createButton() function with
the proper text label and a slot to connect to the button.
- \snippet widgets/widgets/calculator/calculator.cpp 5
- \snippet widgets/widgets/calculator/calculator.cpp 6
+ \snippet widgets/calculator/calculator.cpp 5
+ \snippet widgets/calculator/calculator.cpp 6
The layout is handled by a single QGridLayout. The
QLayout::setSizeConstraint() call ensures that the \c Calculator
column; for these we must also pass a row span and a column
span.
- \snippet widgets/widgets/calculator/calculator.cpp 7
+ \snippet widgets/calculator/calculator.cpp 7
Pressing one of the calculator's digit buttons will emit the
button's \l{QToolButton::clicked()}{clicked()} signal, which will
At the end, we append the new digit to the value in the display.
- \snippet widgets/widgets/calculator/calculator.cpp 8
- \snippet widgets/widgets/calculator/calculator.cpp 9
+ \snippet widgets/calculator/calculator.cpp 8
+ \snippet widgets/calculator/calculator.cpp 9
The \c unaryOperatorClicked() slot is called whenever one of the
unary operator buttons is clicked. Again a pointer to the clicked
digit will be considered as a new operand, instead of being
appended to the current value.
- \snippet widgets/widgets/calculator/calculator.cpp 10
- \snippet widgets/widgets/calculator/calculator.cpp 11
+ \snippet widgets/calculator/calculator.cpp 10
+ \snippet widgets/calculator/calculator.cpp 11
The \c additiveOperatorClicked() slot is called when the user
clicks the \uicontrol{+} or \uicontrol{-} button.
multiplicative operators, since these have higher precedence than
additive operators:
- \snippet widgets/widgets/calculator/calculator.cpp 12
- \snippet widgets/widgets/calculator/calculator.cpp 13
+ \snippet widgets/calculator/calculator.cpp 12
+ \snippet widgets/calculator/calculator.cpp 13
If \uicontrol{\unicode{215}} or \uicontrol{\unicode{247}} has been clicked earlier, without clicking
\uicontrol{=} afterward, the current value in the display is the right
operand of the \uicontrol{\unicode{215}} or \uicontrol{\unicode{247}} operator and we can finally
perform the operation and update the display.
- \snippet widgets/widgets/calculator/calculator.cpp 14
- \snippet widgets/widgets/calculator/calculator.cpp 15
+ \snippet widgets/calculator/calculator.cpp 14
+ \snippet widgets/calculator/calculator.cpp 15
If \uicontrol{+} or \uicontrol{-} has been clicked earlier, \c sumSoFar is
the left operand and the current value in the display is the
operator, \c sumSoFar is simply set to be the text in the
display.
- \snippet widgets/widgets/calculator/calculator.cpp 16
- \snippet widgets/widgets/calculator/calculator.cpp 17
+ \snippet widgets/calculator/calculator.cpp 16
+ \snippet widgets/calculator/calculator.cpp 17
Finally, we can take care of the operator that was just clicked.
Since we don't have the right-hand operand yet, we store the clicked
apply the operation later, when we have a right operand, with \c
sumSoFar as the left operand.
- \snippet widgets/widgets/calculator/calculator.cpp 18
+ \snippet widgets/calculator/calculator.cpp 18
The \c multiplicativeOperatorClicked() slot is similar to \c
additiveOperatorClicked(). We don't need to worry about pending
additive operators here, because multiplicative operators have
precedence over additive operators.
- \snippet widgets/widgets/calculator/calculator.cpp 20
+ \snippet widgets/calculator/calculator.cpp 20
Like in \c additiveOperatorClicked(), we start by handing any
pending multiplicative and additive operators. Then we display \c
sumSoFar and reset the variable to zero. Resetting the variable
to zero is necessary to avoid counting the value twice.
- \snippet widgets/widgets/calculator/calculator.cpp 22
+ \snippet widgets/calculator/calculator.cpp 22
The \c pointClicked() slot adds a decimal point to the content in
\c display.
- \snippet widgets/widgets/calculator/calculator.cpp 24
+ \snippet widgets/calculator/calculator.cpp 24
The \c changeSignClicked() slot changes the sign of the value in
\c display. If the current value is positive, we prepend a minus
sign; if the current value is negative, we remove the first
character from the value (the minus sign).
- \snippet widgets/widgets/calculator/calculator.cpp 26
+ \snippet widgets/calculator/calculator.cpp 26
The \c backspaceClicked() removes the rightmost character in the
display. If we get an empty string, we show "0" and set \c
waitingForOperand to \c true.
- \snippet widgets/widgets/calculator/calculator.cpp 28
+ \snippet widgets/calculator/calculator.cpp 28
The \c clear() slot resets the current operand to zero. It is
equivalent to clicking \uicontrol Backspace enough times to erase the
entire operand.
- \snippet widgets/widgets/calculator/calculator.cpp 30
+ \snippet widgets/calculator/calculator.cpp 30
The \c clearAll() slot resets the calculator to its initial state.
- \snippet widgets/widgets/calculator/calculator.cpp 32
+ \snippet widgets/calculator/calculator.cpp 32
The \c clearMemory() slot erases the sum kept in memory, \c
readMemory() displays the sum as an operand, \c setMemory()
equalClicked() to update \c sumSoFar and the value in the
display.
- \snippet widgets/widgets/calculator/calculator.cpp 34
+ \snippet widgets/calculator/calculator.cpp 34
The private \c createButton() function is called from the
constructor to create calculator buttons.
- \snippet widgets/widgets/calculator/calculator.cpp 36
+ \snippet widgets/calculator/calculator.cpp 36
The private \c abortOperation() function is called whenever a
calculation fails. It resets the calculator state and displays
"####".
- \snippet widgets/widgets/calculator/calculator.cpp 38
+ \snippet widgets/calculator/calculator.cpp 38
The private \c calculate() function performs a binary operation.
The right operand is given by \c rightOperand. For additive
Let's now take a look at the \c Button class:
- \snippet widgets/widgets/calculator/button.h 0
+ \snippet widgets/calculator/button.h 0
The \c Button class has a convenience constructor that takes a
text label and a parent widget, and it reimplements QWidget::sizeHint()
\section1 Button Class Implementation
- \snippet widgets/widgets/calculator/button.cpp 0
+ \snippet widgets/calculator/button.cpp 0
The buttons' appearance is determined by the layout of the
calculator widget through the size and
expand to fill available space. Without this call, the different
buttons in a same column would have different widths.
- \snippet widgets/widgets/calculator/button.cpp 1
- \snippet widgets/widgets/calculator/button.cpp 2
+ \snippet widgets/calculator/button.cpp 1
+ \snippet widgets/calculator/button.cpp 2
In \l{QWidget::sizeHint()}{sizeHint()}, we try to return a size
that looks good for most buttons. We reuse the size hint of the
/*!
\title Calendar Widget Example
- \example widgets/widgets/calendarwidget
+ \example widgets/calendarwidget
The Calendar Widget example shows use of \c QCalendarWidget.
Here is the definition of the \c Window class:
- \snippet widgets/widgets/calendarwidget/window.h 0
+ \snippet widgets/calendarwidget/window.h 0
\dots
- \snippet widgets/widgets/calendarwidget/window.h 1
+ \snippet widgets/calendarwidget/window.h 1
As is often the case with classes that represent self-contained
windows, most of the API is private. We will review the private
Let's now review the class implementation, starting with the constructor:
- \snippet widgets/widgets/calendarwidget/window.cpp 0
+ \snippet widgets/calendarwidget/window.cpp 0
We start by creating the four \l{QGroupBox}es and their child
widgets (including the QCalendarWidget) using four private \c
Let's move on to the \c createPreviewGroupBox() function:
- \snippet widgets/widgets/calendarwidget/window.cpp 9
+ \snippet widgets/calendarwidget/window.cpp 9
The \uicontrol Preview group box contains only one widget: the
QCalendarWidget. We set it up, connect its
and several widgets are set up the same way; we look at parts of
its implementation here and skip the rest:
- \snippet widgets/widgets/calendarwidget/window.cpp 10
+ \snippet widgets/calendarwidget/window.cpp 10
\dots
We start with the setup of the \uicontrol{Week starts on} combobox.
C++ will happily convert any enum value to \c int.
\dots
- \snippet widgets/widgets/calendarwidget/window.cpp 11
+ \snippet widgets/calendarwidget/window.cpp 11
\dots
After creating the widgets, we connect the signals and slots. We
public slots provided by QComboBox.
\dots
- \snippet widgets/widgets/calendarwidget/window.cpp 12
+ \snippet widgets/calendarwidget/window.cpp 12
At the end of the function, we call the slots that update the calendar to ensure
that the QCalendarWidget is synchronized with the other widgets on startup.
Let's now take a look at the \c createDatesGroupBox() private function:
- \snippet widgets/widgets/calendarwidget/window.cpp 13
+ \snippet widgets/calendarwidget/window.cpp 13
In this function, we create the \uicontrol {Minimum Date}, \uicontrol {Maximum Date},
and \uicontrol {Current Date} editor widgets,
set in \c createPrivewGroupBox(); we can then set the widgets
default values to the calendars values.
- \snippet widgets/widgets/calendarwidget/window.cpp 14
+ \snippet widgets/calendarwidget/window.cpp 14
\dots
- \snippet widgets/widgets/calendarwidget/window.cpp 15
+ \snippet widgets/calendarwidget/window.cpp 15
We connect the \c currentDateEdit's
\l{QDateEdit::}{dateChanged()} signal directly to the calendar's
Here is the \c createTextFormatsGroup() function:
- \snippet widgets/widgets/calendarwidget/window.cpp 16
+ \snippet widgets/calendarwidget/window.cpp 16
We set up the \uicontrol {Weekday Color} and \uicontrol {Weekend Color} comboboxes
using \c createColorCombo(), which instantiates a QComboBox and
populates it with colors ("Red", "Blue", etc.).
- \snippet widgets/widgets/calendarwidget/window.cpp 17
+ \snippet widgets/calendarwidget/window.cpp 17
The \uicontrol {Header Text Format} combobox lets the user change the
text format (bold, italic, or plain) used for horizontal and
vertical headers. The \uicontrol {First Friday in blue} and \uicontrol {May 1
in red} check box affect the rendering of specific dates.
- \snippet widgets/widgets/calendarwidget/window.cpp 18
+ \snippet widgets/calendarwidget/window.cpp 18
We connect the check boxes and comboboxes to various private
slots. The \uicontrol {First Friday in blue} and \uicontrol {May 1 in red}
which is also called when the calendar switches month.
\dots
- \snippet widgets/widgets/calendarwidget/window.cpp 19
+ \snippet widgets/calendarwidget/window.cpp 19
At the end of \c createTextFormatsGroupBox(), we call private
slots to synchronize the QCalendarWidget with the other widgets.
functions. Let's now take a look at the other private functions
and slots.
- \snippet widgets/widgets/calendarwidget/window.cpp 20
+ \snippet widgets/calendarwidget/window.cpp 20
In \c createColorCombo(), we create a combobox and populate it with
standard colors. The second argument to QComboBox::addItem()
This function was used to set up the \uicontrol {Weekday Color}
and \uicontrol {Weekend Color} comboboxes.
- \snippet widgets/widgets/calendarwidget/window.cpp 1
+ \snippet widgets/calendarwidget/window.cpp 1
When the user changes the \uicontrol {Week starts on} combobox's
value, \c firstDayChanged() is invoked with the index of the
verticalHeaderChanged() are very similar to \c firstDayChanged(),
so they are omitted.
- \snippet widgets/widgets/calendarwidget/window.cpp 2
+ \snippet widgets/calendarwidget/window.cpp 2
The \c selectedDateChanged() updates the \uicontrol{Current Date}
editor to reflect the current state of the QCalendarWidget.
- \snippet widgets/widgets/calendarwidget/window.cpp 3
+ \snippet widgets/calendarwidget/window.cpp 3
When the user changes the minimum date, we tell the
QCalenderWidget. We also update the \uicontrol {Maximum Date} editor,
date, QCalendarWidget will automatically adapt its maximum date
to avoid a contradicting state.
- \snippet widgets/widgets/calendarwidget/window.cpp 4
+ \snippet widgets/calendarwidget/window.cpp 4
\c maximumDateChanged() is implemented similarly to \c
minimumDateChanged().
- \snippet widgets/widgets/calendarwidget/window.cpp 5
+ \snippet widgets/calendarwidget/window.cpp 5
Each combobox item has a QColor object as user data corresponding to the
item's text. After fetching the colors from the comboboxes, we
specify various character formatting information. In this
example, we only show a subset of the possibilities.
- \snippet widgets/widgets/calendarwidget/window.cpp 6
+ \snippet widgets/calendarwidget/window.cpp 6
\c weekendFormatChanged() is the same as \c
weekdayFormatChanged(), except that it affects Saturday and
Sunday instead of Monday to Friday.
- \snippet widgets/widgets/calendarwidget/window.cpp 7
+ \snippet widgets/calendarwidget/window.cpp 7
The \c reformatHeaders() slot is called when the user
changes the text format of
have been to store \l{QTextCharFormat} values alongside the combobox
items.)
- \snippet widgets/widgets/calendarwidget/window.cpp 8
+ \snippet widgets/calendarwidget/window.cpp 8
In \c reformatCalendarPage(), we set the text format of the first
Friday in the month and May 1 in the current year. The text
****************************************************************************/
/*!
-\example widgets/widgets/charactermap
+\example widgets/charactermap
\title Character Map Example
The Character Map example shows how to create a custom widget that can
The class definition looks like this:
-\snippet widgets/widgets/charactermap/characterwidget.h 0
+\snippet widgets/charactermap/characterwidget.h 0
The widget does not contain any other widgets, so it must provide its own
size hint to allow its contents to be displayed correctly.
calls the base class constructor and defines some default values for
private data members.
-\snippet widgets/widgets/charactermap/characterwidget.cpp 0
+\snippet widgets/charactermap/characterwidget.cpp 0
We initialize \c currentKey with a value of -1 to indicate
that no character is initially selected. We enable mouse tracking to
The class provides two functions to allow the font and style to be set up.
Each of these modify the widget's display font and call update():
-\snippet widgets/widgets/charactermap/characterwidget.cpp 1
+\snippet widgets/charactermap/characterwidget.cpp 1
\codeline
-\snippet widgets/widgets/charactermap/characterwidget.cpp 2
+\snippet widgets/charactermap/characterwidget.cpp 2
We use a fixed size font for the display. Similarly, a fixed size hint is
provided by the sizeHint() function:
-\snippet widgets/widgets/charactermap/characterwidget.cpp 3
+\snippet widgets/charactermap/characterwidget.cpp 3
Three standard event functions are implemented so that the widget
can respond to clicks, provide tooltips, and render the available
characters. The paintEvent() shows how the contents of the widget are
arranged and displayed:
-\snippet widgets/widgets/charactermap/characterwidget.cpp 6
+\snippet widgets/charactermap/characterwidget.cpp 6
A QPainter is created for the widget and, in all cases, we ensure that the
widget's background is painted. The painter's font is set to the
The area of the widget that needs to be redrawn is used to determine which
characters need to be displayed:
-\snippet widgets/widgets/charactermap/characterwidget.cpp 7
+\snippet widgets/charactermap/characterwidget.cpp 7
Using integer division, we obtain the row and column numbers of each
characters that should be displayed, and we draw a square on the widget
for each character displayed.
-\snippet widgets/widgets/charactermap/characterwidget.cpp 8
-\snippet widgets/widgets/charactermap/characterwidget.cpp 9
+\snippet widgets/charactermap/characterwidget.cpp 8
+\snippet widgets/charactermap/characterwidget.cpp 9
The symbols for each character in the array are drawn within each square,
with the symbol for the most recently selected character displayed in red:
-\snippet widgets/widgets/charactermap/characterwidget.cpp 10
+\snippet widgets/charactermap/characterwidget.cpp 10
We do not need to take into account the difference between the area
displayed in the viewport and the area we are drawing on because
The mousePressEvent() defines how the widget responds to mouse clicks.
-\snippet widgets/widgets/charactermap/characterwidget.cpp 5
+\snippet widgets/charactermap/characterwidget.cpp 5
We are only interested when the user clicks with the left mouse button
over the widget. When this happens, we calculate which character was
coordinates to widget coordinates, and determines the character that
was clicked by performing the calculation
-\snippet widgets/widgets/charactermap/characterwidget.cpp 4
+\snippet widgets/charactermap/characterwidget.cpp 4
The tooltip is given a position defined in global coordinates.
The class definition looks like this:
-\snippet widgets/widgets/charactermap/mainwindow.h 0
+\snippet widgets/charactermap/mainwindow.h 0
The main window contains various widgets that are used to control how
the characters will be displayed, and defines the findFonts() function
We also construct a CharacterWidget custom widget, and add a QScrollArea
so that we can view its contents:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 0
+\snippet widgets/charactermap/mainwindow.cpp 0
QScrollArea provides a viewport onto the \c CharacterWidget when we set
its widget and handles much of the work needed to provide a scrolling
fonts. We list the available styles for the current font in the style
combobox using the following function:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 1
+\snippet widgets/charactermap/mainwindow.cpp 1
The line edit and push button are used to supply text to the clipboard:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 2
+\snippet widgets/charactermap/mainwindow.cpp 2
We also obtain a clipboard object so that we can send text entered by the
user to other applications.
We connect these signals to slots in this class, and to the slots provided
by other widgets.
-\snippet widgets/widgets/charactermap/mainwindow.cpp 4
+\snippet widgets/charactermap/mainwindow.cpp 4
The font combobox's
\l{QFontComboBox::currentFontChanged()}{currentFontChanged()} signal is
The final two connections allow characters to be selected in the character
widget, and text to be inserted into the clipboard:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 5
+\snippet widgets/charactermap/mainwindow.cpp 5
The character widget emits the characterSelected() custom signal when
the user clicks on a character, and this is handled by the insertCharacter()
The remaining code in the constructor sets up the layout of the central widget,
and provides a window title:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 6
+\snippet widgets/charactermap/mainwindow.cpp 6
The font combobox is automatically populated with a list of available font
families. The styles that can be used with each font are found by the
findStyles() function. This function is called whenever the user selects a
different font in the font combobox.
-\snippet widgets/widgets/charactermap/mainwindow.cpp 7
+\snippet widgets/charactermap/mainwindow.cpp 7
We begin by recording the currently selected style, and we clear the
style combobox so that we can insert the styles associated with the
current font family.
-\snippet widgets/widgets/charactermap/mainwindow.cpp 8
+\snippet widgets/charactermap/mainwindow.cpp 8
We use the font database to collect the styles that are available for the
current font, and insert them into the style combobox. The current item is
used to insert characters from the character widget when the user clicks a
character:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 9
+\snippet widgets/charactermap/mainwindow.cpp 9
The character is inserted into the line edit at the current cursor position.
updateClipboard() function so that, when it is clicked, the clipboard is
updated to contain the contents of the line edit:
-\snippet widgets/widgets/charactermap/mainwindow.cpp 10
+\snippet widgets/charactermap/mainwindow.cpp 10
We copy all the text from the line edit to the clipboard, but we do not clear
the line edit.
indexAt(). However, the view needs to maintain strict control over its look and
feel, so we also provide implementations for a number of other functions:
- \snippet widgets/widgets/itemviews/chart/pieview.h 0
+ \snippet widgets/itemviews/chart/pieview.h 0
****************************************************************************/
/*!
- \example widgets/widgets/codeeditor
+ \example widgets/codeeditor
\title Code Editor Example
The Code Editor example shows how to create a simple editor that
extend the editor with breakpoints or other code editor features.
The widget would then help in the handling of mouse events.
- \snippet widgets/widgets/codeeditor/codeeditor.h extraarea
+ \snippet widgets/codeeditor/codeeditor.h extraarea
\section1 CodeEditor Class Definition
Here is the code editor's class definition:
- \snippet widgets/widgets/codeeditor/codeeditor.h codeeditordefinition
+ \snippet widgets/codeeditor/codeeditor.h codeeditordefinition
In the editor we resize and draw the line numbers on the \c
LineNumberArea. We need to do this when the number of lines in the
We will now go through the code editors implementation, starting
off with the constructor.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp constructor
+ \snippet widgets/codeeditor/codeeditor.cpp constructor
In the constructor we connect our slots to signals in
QPlainTextEdit. It is necessary to calculate the line number area
width and highlight the first line when the editor is created.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp extraAreaWidth
+ \snippet widgets/codeeditor/codeeditor.cpp extraAreaWidth
The \c lineNumberAreaWidth() function calculates the width of the
\c LineNumberArea widget. We take the number of digits in the last
line of the editor and multiply that with the maximum width of a
digit.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp slotUpdateExtraAreaWidth
+ \snippet widgets/codeeditor/codeeditor.cpp slotUpdateExtraAreaWidth
When we update the width of the line number area, we simply call
QAbstractScrollArea::setViewportMargins().
- \snippet widgets/widgets/codeeditor/codeeditor.cpp slotUpdateRequest
+ \snippet widgets/codeeditor/codeeditor.cpp slotUpdateRequest
This slot is invoked when the editors viewport has been scrolled.
The QRect given as argument is the part of the editing area that
is do be updated (redrawn). \c dy holds the number of pixels the
view has been scrolled vertically.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp resizeEvent
+ \snippet widgets/codeeditor/codeeditor.cpp resizeEvent
When the size of the editor changes, we also need to resize the
line number area.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp cursorPositionChanged
+ \snippet widgets/codeeditor/codeeditor.cpp cursorPositionChanged
When the cursor position changes, we highlight the current line,
i.e., the line containing the cursor.
block, the cursor should be moved with QTextCursor::movePosition()
from a position set with \l{QTextCursor::}{setPosition()}.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_0
+ \snippet widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_0
The \c lineNumberAreaPaintEvent() is called from \c LineNumberArea
whenever it receives a paint event. We start off by painting the
widget's background.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_1
+ \snippet widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_1
We will now loop through all visible lines and paint the line
numbers in the extra area for each line. Notice that in a plain
and adjust these values by the height of the current text block in
each iteration in the loop.
- \snippet widgets/widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_2
+ \snippet widgets/codeeditor/codeeditor.cpp extraAreaPaintEvent_2
Notice that we check if the block is visible in addition to check
if it is in the areas viewport - a block can, for example, be
****************************************************************************/
/*!
- \example widgets/widgets/digitalclock
+ \example widgets/digitalclock
\title Digital Clock Example
The Digital Clock example shows how to use QLCDNumber to display a
and implement a private slot called \c showTime() to update the clock
display:
- \snippet widgets/widgets/digitalclock/digitalclock.h 0
+ \snippet widgets/digitalclock/digitalclock.h 0
\section1 DigitalClock Class Implementation
- \snippet widgets/widgets/digitalclock/digitalclock.cpp 0
+ \snippet widgets/digitalclock/digitalclock.cpp 0
In the constructor, we first change the look of the LCD numbers. The
QLCDNumber::Filled style produces raised segments filled with the
call the \c showTime() slot; without this call, there would be a one-second
delay at startup before the time is shown.
- \snippet widgets/widgets/digitalclock/digitalclock.cpp 1
- \snippet widgets/widgets/digitalclock/digitalclock.cpp 2
+ \snippet widgets/digitalclock/digitalclock.cpp 1
+ \snippet widgets/digitalclock/digitalclock.cpp 2
The \c showTime() slot is called whenever the clock display needs
to be updated.
****************************************************************************/
/*!
- \example widgets/widgets/elidedlabel
+ \example widgets/elidedlabel
\group all-examples
\title Elided Label Example
the \c ElidedLabel class:
- \snippet widgets/widgets/elidedlabel/elidedlabel.h 0
+ \snippet widgets/elidedlabel/elidedlabel.h 0
The \c isElided property depends the font, text content and geometry of the
widget. Whenever any of these change, the \c elisionChanged() signal might
policy to be horizontally expanding, since it's meant to fill the width of
its container and grow vertically.
- \snippet widgets/widgets/elidedlabel/elidedlabel.cpp 0
+ \snippet widgets/elidedlabel/elidedlabel.cpp 0
Changing the \c content require a repaint of the widget.
- \snippet widgets/widgets/elidedlabel/elidedlabel.cpp 1
+ \snippet widgets/elidedlabel/elidedlabel.cpp 1
QTextLayout is used in the \c paintEvent() to divide the \c content into
lines, that wrap on word boundaries. Each line, except the last visible
method of QTextLine will draw the line using the coordinate point as the
top left corner.
- \snippet widgets/widgets/elidedlabel/elidedlabel.cpp 2
+ \snippet widgets/elidedlabel/elidedlabel.cpp 2
Unfortunately, QTextLayout does not elide text, so the last visible line
has to be treated differently. This last line is elided if it is too wide.
Finally, one more line is created to see if everything fit on this line.
- \snippet widgets/widgets/elidedlabel/elidedlabel.cpp 3
+ \snippet widgets/elidedlabel/elidedlabel.cpp 3
If the text was elided and wasn't before or vice versa, cache it in
\c elided and emit the change.
- \snippet widgets/widgets/elidedlabel/elidedlabel.cpp 4
+ \snippet widgets/elidedlabel/elidedlabel.cpp 4
\section1 TestWidget Class Definition
\c TestWidget is a QWidget and is the main window of the example. It
contains an \c ElidedLabel which can be resized with two QSlider widgets.
- \snippet widgets/widgets/elidedlabel/testwidget.h 0
+ \snippet widgets/elidedlabel/testwidget.h 0
\section1 TestWidget Class Implementation
The constructor initializes the whole widget. Strings of different length
are stored in \c textSamples. The user is able to switch between these.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 0
+ \snippet widgets/elidedlabel/testwidget.cpp 0
An \c ElidedLabel is created to contain the first of the sample strings.
The frame is made visible to make it easier to see the actual size of the
widget.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 1
+ \snippet widgets/elidedlabel/testwidget.cpp 1
The buttons and the elision label are created. By connecting the
\c elisionChanged() signal to the \c setVisible() slot of the \c label,
it will act as an indicator to when the text is elided or not. This signal
could, for instance, be used to make a "More" button visible, or similar.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 2
+ \snippet widgets/elidedlabel/testwidget.cpp 2
The \c widthSlider and \c heightSlider specify the size of the
\c elidedText. Since the y-axis is inverted, the \c heightSlider has to be
inverted to act appropriately.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 3
+ \snippet widgets/elidedlabel/testwidget.cpp 3
The components are all stored in a QGridLayout, which is made the layout of
the \c TestWidget.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 4
+ \snippet widgets/elidedlabel/testwidget.cpp 4
On the Maemo platform, windows are stuck in landscape mode by default. With
this attribute set, the window manager is aware that this window can be
rotated.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 5
+ \snippet widgets/elidedlabel/testwidget.cpp 5
The \c widthSlider and \c heightSlider have the exact same length as the
dimensions of the \c elidedText. The maximum value for both of them is
thus their lengths, and each tick indicates one pixel.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 6
+ \snippet widgets/elidedlabel/testwidget.cpp 6
The \c switchText() slot simply cycles through all the available sample
texts.
- \snippet widgets/widgets/elidedlabel/testwidget.cpp 7
+ \snippet widgets/elidedlabel/testwidget.cpp 7
These slots set the width and height of the \c elided text, in response to
changes in the sliders.
The \c main() function creates an instance of \c TestWidget fullscreen and
enters the message loop.
- \snippet widgets/widgets/elidedlabel/main.cpp 0
+ \snippet widgets/elidedlabel/main.cpp 0
*/
****************************************************************************/
/*!
- \example widgets/widgets/groupbox
+ \example widgets/groupbox
\title Group Box Example
The Group Box example shows how to use the different kinds of group
functions to construct each group box and populate it with different
selections of button widgets:
- \snippet widgets/widgets/groupbox/window.h 0
+ \snippet widgets/groupbox/window.h 0
In the example, the widget will be used as a top-level window, so
the constructor is defined so that we do not have to specify a parent
The constructor creates a grid layout and fills it with each of the
group boxes that are to be displayed:
- \snippet widgets/widgets/groupbox/window.cpp 0
+ \snippet widgets/groupbox/window.cpp 0
The functions used to create each group box each return a
QGroupBox to be inserted into the grid layout.
- \snippet widgets/widgets/groupbox/window.cpp 1
+ \snippet widgets/groupbox/window.cpp 1
The first group box contains and manages three radio buttons. Since
the group box contains only radio buttons, it is exclusive by
We check the first radio button to ensure that the button group
contains one checked button.
- \snippet widgets/widgets/groupbox/window.cpp 3
+ \snippet widgets/groupbox/window.cpp 3
We use a vertical layout within the group box to present the
buttons in the form of a vertical list, and return the group
unchecked, so the group box itself must be checked before any of
the radio buttons inside can be checked.
- \snippet widgets/widgets/groupbox/window.cpp 4
+ \snippet widgets/groupbox/window.cpp 4
The group box contains three exclusive radio buttons, and an
independent checkbox. For consistency, one radio button must be
checked at all times, so we ensure that the first one is initially
checked.
- \snippet widgets/widgets/groupbox/window.cpp 5
+ \snippet widgets/groupbox/window.cpp 5
The buttons are arranged in the same way as those in the first
group box.
- \snippet widgets/widgets/groupbox/window.cpp 6
+ \snippet widgets/groupbox/window.cpp 6
The third group box is constructed with a "flat" style that is
better suited to certain types of dialog.
- \snippet widgets/widgets/groupbox/window.cpp 7
+ \snippet widgets/groupbox/window.cpp 7
This group box contains only checkboxes, so it is non-exclusive by
default. This means that each checkbox can be checked independently
of the others.
- \snippet widgets/widgets/groupbox/window.cpp 8
+ \snippet widgets/groupbox/window.cpp 8
Again, we use a vertical layout within the group box to present
the buttons in the form of a vertical list.
- \snippet widgets/widgets/groupbox/window.cpp 9
+ \snippet widgets/groupbox/window.cpp 9
The final group box contains only push buttons and, like the
second group box, it is checkable.
- \snippet widgets/widgets/groupbox/window.cpp 10
+ \snippet widgets/groupbox/window.cpp 10
We create a normal button, a toggle button, and a flat push button:
- \snippet widgets/widgets/groupbox/window.cpp 11
+ \snippet widgets/groupbox/window.cpp 11
Push buttons can be used to display popup menus. We create one, and
attach a simple menu to it:
- \snippet widgets/widgets/groupbox/window.cpp 12
+ \snippet widgets/groupbox/window.cpp 12
Finally, we lay out the widgets vertically, and return the group box
that we created:
- \snippet widgets/widgets/groupbox/window.cpp 13
+ \snippet widgets/groupbox/window.cpp 13
*/
****************************************************************************/
/*!
- \example widgets/widgets/icons
+ \example widgets/icons
\title Icons Example
The Icons example shows how QIcon can generate pixmaps reflecting
\image icons_preview_area.png Screenshot of IconPreviewArea.
- \snippet widgets/widgets/icons/iconpreviewarea.h 0
+ \snippet widgets/icons/iconpreviewarea.h 0
The \c IconPreviewArea class inherits QWidget. It displays the
generated pixmaps corresponding to an icon's possible states and
\section2 IconPreviewArea Class Implementation
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 0
+ \snippet widgets/icons/iconpreviewarea.cpp 0
In the constructor we create the labels displaying the headers and
the icon's generated pixmaps, and add them to a grid layout.
Another approach is to add this line directly to the \c .pro
file.
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 1
+ \snippet widgets/icons/iconpreviewarea.cpp 1
\codeline
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 2
+ \snippet widgets/icons/iconpreviewarea.cpp 2
The public \c setIcon() and \c setSize() functions change the icon
or the icon size, and make sure that the generated pixmaps are
updated.
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 3
+ \snippet widgets/icons/iconpreviewarea.cpp 3
\codeline
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 4
+ \snippet widgets/icons/iconpreviewarea.cpp 4
We use the \c createHeaderLabel() and \c createPixmapLabel()
functions to create the preview area's labels displaying the
headers and the icon's generated pixmaps. Both functions return
the QLabel that is created.
- \snippet widgets/widgets/icons/iconpreviewarea.cpp 5
+ \snippet widgets/icons/iconpreviewarea.cpp 5
We use the private \c updatePixmapLabel() function to update the
generated pixmaps displayed in the preview area.
\image icons-example.png Screenshot of the Icons example
- \snippet widgets/widgets/icons/mainwindow.h 0
+ \snippet widgets/icons/mainwindow.h 0
The MainWindow class inherits from QMainWindow. We reimplement the
constructor, and declare several private slots:
\section2 MainWindow Class Implementation
- \snippet widgets/widgets/icons/mainwindow.cpp 0
+ \snippet widgets/icons/mainwindow.cpp 0
In the constructor we first create the main window's central
widget and its child widgets, and put them in a grid layout. Then
associated radio button, making the current value of the spin box
the icon's initial size.
- \snippet widgets/widgets/icons/mainwindow.cpp 1
+ \snippet widgets/icons/mainwindow.cpp 1
The \c about() slot displays a message box using the static
QMessageBox::about() function. In this example it displays a
parent, and if that fails, it tries the active window. As a last
resort it uses the QMessageBox's Information icon.
- \snippet widgets/widgets/icons/mainwindow.cpp 2
+ \snippet widgets/icons/mainwindow.cpp 2
In the \c changeStyle() slot we first check the slot's
parameter. If it is false we immediately return, otherwise we find
pointers are much easier to diagnose than crashes due to unsafe
casts.
- \snippet widgets/widgets/icons/mainwindow.cpp 3
- \snippet widgets/widgets/icons/mainwindow.cpp 4
+ \snippet widgets/icons/mainwindow.cpp 3
+ \snippet widgets/icons/mainwindow.cpp 4
Once we have the action, we extract the style name using
QAction::data(). Then we create a QStyle object using the static
group box and in the end call the \c changeSize() slot to update
the icon's size.
- \snippet widgets/widgets/icons/mainwindow.cpp 5
+ \snippet widgets/icons/mainwindow.cpp 5
The \c changeSize() slot sets the size for the preview area's
icon.
based on the extent, and use that object to set the size of the
preview area's icon.
- \snippet widgets/widgets/icons/mainwindow.cpp 12
+ \snippet widgets/icons/mainwindow.cpp 12
The first thing we do when the \c addImage() slot is called, is to
show a file dialog to the user. The easiest way to create a file
table widget. The table widget is listing the images the user has
loaded into the application.
- \snippet widgets/widgets/icons/mainwindow.cpp 13
- \snippet widgets/widgets/icons/mainwindow.cpp 14
+ \snippet widgets/icons/mainwindow.cpp 13
+ \snippet widgets/icons/mainwindow.cpp 14
We retrieve the image name using the QFileInfo::baseName()
function that returns the base name of the file without the path,
We also make sure that the item is not editable by removing the
Qt::ItemIsEditable flag. Table items are editable by default.
- \snippet widgets/widgets/icons/mainwindow.cpp 15
- \snippet widgets/widgets/icons/mainwindow.cpp 16
- \snippet widgets/widgets/icons/mainwindow.cpp 17
+ \snippet widgets/icons/mainwindow.cpp 15
+ \snippet widgets/icons/mainwindow.cpp 16
+ \snippet widgets/icons/mainwindow.cpp 17
Then we create the second and third items in the row making the
default mode Normal and the default state Off. But if the \uicontrol
"_on", the state is changed to On. The sample files in the
example's \c images subdirectory respect this naming convension.
- \snippet widgets/widgets/icons/mainwindow.cpp 18
- \snippet widgets/widgets/icons/mainwindow.cpp 19
+ \snippet widgets/icons/mainwindow.cpp 18
+ \snippet widgets/icons/mainwindow.cpp 19
In the end we add the items to the associated row, and use the
QTableWidget::openPersistentEditor() function to create
in the preview area. So, corresponding to this fact, we need to
make sure that the new image's check box is enabled.
- \snippet widgets/widgets/icons/mainwindow.cpp 6
- \snippet widgets/widgets/icons/mainwindow.cpp 7
+ \snippet widgets/icons/mainwindow.cpp 6
+ \snippet widgets/icons/mainwindow.cpp 7
The \c changeIcon() slot is called when the user alters the set
of images listed in the QTableWidget, to update the QIcon object
QTableWidget, which lists the images the user has loaded into the
application.
- \snippet widgets/widgets/icons/mainwindow.cpp 8
- \snippet widgets/widgets/icons/mainwindow.cpp 9
- \snippet widgets/widgets/icons/mainwindow.cpp 10
+ \snippet widgets/icons/mainwindow.cpp 8
+ \snippet widgets/icons/mainwindow.cpp 9
+ \snippet widgets/icons/mainwindow.cpp 10
We also extract the image file's name using the
QTableWidgetItem::data() function. This function takes a
with its associated mode and state, to the QIcon's set of
available pixmaps.
- \snippet widgets/widgets/icons/mainwindow.cpp 11
+ \snippet widgets/icons/mainwindow.cpp 11
After running through the entire list of images, we change the
icon of the preview area to the one we just created.
- \snippet widgets/widgets/icons/mainwindow.cpp 20
+ \snippet widgets/icons/mainwindow.cpp 20
In the \c removeAllImages() slot, we simply set the table widget's
row count to zero, automatically removing all the images the user
QTableWidget that will keep track of the images the user has
loaded into the application.
- \snippet widgets/widgets/icons/mainwindow.cpp 21
+ \snippet widgets/icons/mainwindow.cpp 21
First we create a group box that will contain the table widget.
Then we create a QTableWidget and customize it to suit our
\c ImageDelegate, provides comboboxes for the mode and state
fields.
- \snippet widgets/widgets/icons/mainwindow.cpp 22
- \snippet widgets/widgets/icons/mainwindow.cpp 23
+ \snippet widgets/icons/mainwindow.cpp 22
+ \snippet widgets/icons/mainwindow.cpp 23
Then we customize the QTableWidget's horizontal header, and hide
the vertical header.
- \snippet widgets/widgets/icons/mainwindow.cpp 24
- \snippet widgets/widgets/icons/mainwindow.cpp 25
+ \snippet widgets/icons/mainwindow.cpp 24
+ \snippet widgets/icons/mainwindow.cpp 25
At the end, we connect the QTableWidget::itemChanged() signal to
the \c changeIcon() slot to ensuret that the preview area is in
constructor. It creates the widgets controlling the size of the
preview area's icon.
- \snippet widgets/widgets/icons/mainwindow.cpp 26
+ \snippet widgets/icons/mainwindow.cpp 26
First we create a group box that will contain all the widgets;
then we create the radio buttons and the spin box.
handle icon sizes, e.g., "32 x 32", instead of plain integer
values.
- \snippet widgets/widgets/icons/mainwindow.cpp 27
+ \snippet widgets/icons/mainwindow.cpp 27
Then we connect all of the radio buttons
\l{QRadioButton::toggled()}{toggled()} signals and the spin box's
In the end we put the widgets in a layout that we install on the
group box.
- \snippet widgets/widgets/icons/mainwindow.cpp 28
+ \snippet widgets/icons/mainwindow.cpp 28
In the \c createActions() function we create and customize all the
actions needed to implement the functionality associated with the
with the style name. We will retrieve it later using
QAction::data().
- \snippet widgets/widgets/icons/mainwindow.cpp 29
+ \snippet widgets/icons/mainwindow.cpp 29
In the \c createMenu() function, we add the previously created
actions to the \uicontrol File, \uicontrol View and \uicontrol Help menus.
application's menu bar, which we retrieve using
QMainWindow::menuBar().
- \snippet widgets/widgets/icons/mainwindow.cpp 30
+ \snippet widgets/icons/mainwindow.cpp 30
QWidgets have a \l{QWidget::contextMenuPolicy}{contextMenuPolicy}
property that controls how the widget should behave when the user
actions to the table widget. They will then appear in the table
widget's context menu.
- \snippet widgets/widgets/icons/mainwindow.cpp 31
+ \snippet widgets/icons/mainwindow.cpp 31
In the \c checkCurrentStyle() function we go through the group of
style actions, looking for the current GUI style.
\section2 IconSizeSpinBox Class Definition
- \snippet widgets/widgets/icons/iconsizespinbox.h 0
+ \snippet widgets/icons/iconsizespinbox.h 0
The \c IconSizeSpinBox class is a subclass of QSpinBox. A plain
QSpinBox can only handle integers. But since we want to display
\section2 IconSizeSpinBox Class Implementation
- \snippet widgets/widgets/icons/iconsizespinbox.cpp 0
+ \snippet widgets/icons/iconsizespinbox.cpp 0
The constructor is trivial.
- \snippet widgets/widgets/icons/iconsizespinbox.cpp 2
+ \snippet widgets/icons/iconsizespinbox.cpp 2
QSpinBox::textFromValue() is used by the spin box whenever it
needs to display a value. The default implementation returns a
Our reimplementation returns a QString of the form "32 x 32".
- \snippet widgets/widgets/icons/iconsizespinbox.cpp 1
+ \snippet widgets/icons/iconsizespinbox.cpp 1
The QSpinBox::valueFromText() function is used by the spin box
whenever it needs to interpret text typed in by the user. Since
\section2 ImageDelegate Class Definition
- \snippet widgets/widgets/icons/imagedelegate.h 0
+ \snippet widgets/icons/imagedelegate.h 0
The \c ImageDelegate class is a subclass of QItemDelegate. The
QItemDelegate class provides display and editing facilities for
for this purpose allows the editing mechanism to be customized and
developed independently from the model and view.
- \snippet widgets/widgets/icons/imagedelegate.h 1
+ \snippet widgets/icons/imagedelegate.h 1
The default implementation of QItemDelegate creates a QLineEdit.
Since we want the editor to be a QComboBox, we need to subclass
QItemDelegate::setEditorData() and QItemDelegate::setModelData()
functions.
- \snippet widgets/widgets/icons/imagedelegate.h 2
+ \snippet widgets/icons/imagedelegate.h 2
The \c emitCommitData() slot is used to emit the
QImageDelegate::commitData() signal with the appropriate
\section2 ImageDelegate Class Implementation
- \snippet widgets/widgets/icons/imagedelegate.cpp 0
+ \snippet widgets/icons/imagedelegate.cpp 0
The constructor is trivial.
- \snippet widgets/widgets/icons/imagedelegate.cpp 1
+ \snippet widgets/icons/imagedelegate.cpp 1
The default QItemDelegate::createEditor() implementation returns
the widget used to edit the item specified by the model and item
chooses an item using the combobox. This ensures that the rest of
the application notices the change and updates itself.
- \snippet widgets/widgets/icons/imagedelegate.cpp 2
+ \snippet widgets/icons/imagedelegate.cpp 2
The QItemDelegate::setEditorData() function is used by
QTableWidget to transfer data from a QTableWidgetItem to the
items is done implicitly by QTableWidget; we don't need to worry
about it.
- \snippet widgets/widgets/icons/imagedelegate.cpp 3
+ \snippet widgets/icons/imagedelegate.cpp 3
The QItemDelegate::setEditorData() function is used by QTableWidget
to transfer data back from the editor to the \l{QTableWidgetItem}.
- \snippet widgets/widgets/icons/imagedelegate.cpp 4
+ \snippet widgets/icons/imagedelegate.cpp 4
The \c emitCommitData() slot simply emit the
QAbstractItemDelegate::commitData() signal for the editor that
****************************************************************************/
/*!
- \example widgets/widgets/imageviewer
+ \example widgets/imageviewer
\title Image Viewer Example
The example shows how to combine QLabel and QScrollArea to
\section1 ImageViewer Class Definition
- \snippet widgets/widgets/imageviewer/imageviewer.h 0
+ \snippet widgets/imageviewer/imageviewer.h 0
The \c ImageViewer class inherits from QMainWindow. We reimplement
the constructor, and create several private slots to facilitate
\section1 ImageViewer Class Implementation
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 0
+ \snippet widgets/imageviewer/imageviewer.cpp 0
In the constructor we first create the label and the scroll area.
we create the associated actions and menus, and customize the \c
{ImageViewer}'s appearance.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 1
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 2
+ \snippet widgets/imageviewer/imageviewer.cpp 1
+ \snippet widgets/imageviewer/imageviewer.cpp 2
In the \c open() slot, we show a file dialog to the user. The
easiest way to create a QFileDialog is to use the static
information message with an \uicontrol OK button (the default) is
sufficient, since the message is part of a normal operation.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 3
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 4
+ \snippet widgets/imageviewer/imageviewer.cpp 3
+ \snippet widgets/imageviewer/imageviewer.cpp 4
If the format is supported, we display the image in \c imageLabel
by setting the label's \l {QLabel::pixmap}{pixmap}. Then we enable
In the \c print() slot, we first make sure that an image has been
loaded into the application:
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 5
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 6
+ \snippet widgets/imageviewer/imageviewer.cpp 5
+ \snippet widgets/imageviewer/imageviewer.cpp 6
If the application is built in debug mode, the \c Q_ASSERT() macro
will expand to
Another approach is to add this line directly to the \c .pro
file.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 7
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 8
+ \snippet widgets/imageviewer/imageviewer.cpp 7
+ \snippet widgets/imageviewer/imageviewer.cpp 8
Then we present a print dialog allowing the user to choose a
printer and to set a few options. We construct a painter with a
In the end we draw the pixmap at position (0, 0).
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 9
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 10
+ \snippet widgets/imageviewer/imageviewer.cpp 9
+ \snippet widgets/imageviewer/imageviewer.cpp 10
We implement the zooming slots using the private \c scaleImage()
function. We set the scaling factors to 1.25 and 0.8,
\li \inlineimage imageviewer-zoom_in_2.png
\endtable
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 11
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 12
+ \snippet widgets/imageviewer/imageviewer.cpp 11
+ \snippet widgets/imageviewer/imageviewer.cpp 12
When zooming, we use the QLabel's ability to scale its contents.
Such scaling doesn't change the actual size hint of the contents.
normal size of the currently displayed image is to call \c
adjustSize() and reset the scale factor to 1.0.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 13
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 14
+ \snippet widgets/imageviewer/imageviewer.cpp 13
+ \snippet widgets/imageviewer/imageviewer.cpp 14
The \c fitToWindow() slot is called each time the user toggled
the \uicontrol {Fit to Window} option. If the slot is called to turn on
label's size to its content. And in the end we update the view
menu entries.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 15
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 16
+ \snippet widgets/imageviewer/imageviewer.cpp 15
+ \snippet widgets/imageviewer/imageviewer.cpp 16
We implement the \c about() slot to create a message box
describing what the example is designed to show.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 17
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 18
+ \snippet widgets/imageviewer/imageviewer.cpp 17
+ \snippet widgets/imageviewer/imageviewer.cpp 18
In the private \c createAction() function, we create the
actions providing the application features.
been loaded into the application. In addition we make the \c
fitToWindowAct \l {QAction::checkable}{checkable}.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 19
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 20
+ \snippet widgets/imageviewer/imageviewer.cpp 19
+ \snippet widgets/imageviewer/imageviewer.cpp 20
In the private \c createMenu() function, we add the previously
created actions to the \uicontrol File, \uicontrol View and \uicontrol Help menus.
menu bar which we retrieve with the QMainWindow::menuBar()
function.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 21
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 22
+ \snippet widgets/imageviewer/imageviewer.cpp 21
+ \snippet widgets/imageviewer/imageviewer.cpp 22
The private \c updateActions() function enables or disables the
\uicontrol {Zoom In}, \uicontrol {Zoom Out} and \uicontrol {Normal Size} menu
entries depending on whether the \uicontrol {Fit to Window} option is
turned on or off.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 23
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 24
+ \snippet widgets/imageviewer/imageviewer.cpp 23
+ \snippet widgets/imageviewer/imageviewer.cpp 24
In \c scaleImage(), we use the \c factor parameter to calculate
the new scaling factor for the displayed image, and resize \c
image pixmap from becoming too large, consuming too much
resources in the window system.
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 25
- \snippet widgets/widgets/imageviewer/imageviewer.cpp 26
+ \snippet widgets/imageviewer/imageviewer.cpp 25
+ \snippet widgets/imageviewer/imageviewer.cpp 26
Whenever we zoom in or out, we need to adjust the scroll bars in
consequence. It would have been tempting to simply call
****************************************************************************/
/*!
- \example widgets/widgets/lineedits
+ \example widgets/lineedits
\title Line Edits Example
The Line Edits example demonstrates the many ways that QLineEdit can be used, and
The \c Window class inherits QWidget and contains a constructor and several
slots:
- \snippet widgets/widgets/lineedits/window.h 0
+ \snippet widgets/lineedits/window.h 0
The slots are used to update the type of validator used for a given line edit when
a new validator has been selected in the associated combobox. The line edits
We begin by constructing a \l{QGroupBox}{group box} to hold a label, combobox,
and line edit so that we can demonstrate the QLineEdit::echoMode property:
- \snippet widgets/widgets/lineedits/window.cpp 0
+ \snippet widgets/lineedits/window.cpp 0
At this point, none of these widgets have been arranged in layouts. Eventually,
the \c echoLabel, \c echoComboBox, and \c echoLineEdit will be placed in a
Similarly, we construct group boxes and collections of widgets to show the
effects of QIntValidator and QDoubleValidator on a line edit's contents:
- \snippet widgets/widgets/lineedits/window.cpp 1
+ \snippet widgets/lineedits/window.cpp 1
Text alignment is demonstrated by another group of widgets:
- \snippet widgets/widgets/lineedits/window.cpp 2
+ \snippet widgets/lineedits/window.cpp 2
QLineEdit supports the use of \l{QLineEdit::inputMask}{input masks}.
These only allow the user to type characters into the line edit that
follow a simple specification. We construct a group of widgets to
demonstrate a selection of predefined masks:
- \snippet widgets/widgets/lineedits/window.cpp 3
+ \snippet widgets/lineedits/window.cpp 3
Another useful feature of QLineEdit is its ability to make its contents
read-only. This property is used to control access to a line edit in the
following group of widgets:
- \snippet widgets/widgets/lineedits/window.cpp 4
+ \snippet widgets/lineedits/window.cpp 4
Now that all the child widgets have been constructed, we connect signals
from the comboboxes to slots in the \c Window object:
- \snippet widgets/widgets/lineedits/window.cpp 5
+ \snippet widgets/lineedits/window.cpp 5
Each of these connections use the QComboBox::activated() signal that
supplies an integer to the slot. This will be used to efficiently
We place each combobox, line edit, and label in a layout for each group
box, beginning with the layout for the \c echoGroup group box:
- \snippet widgets/widgets/lineedits/window.cpp 6
+ \snippet widgets/lineedits/window.cpp 6
The other layouts are constructed in the same way:
- \snippet widgets/widgets/lineedits/window.cpp 7
+ \snippet widgets/lineedits/window.cpp 7
Finally, we place each group box in a grid layout for the \c Window object
and set the window title:
- \snippet widgets/widgets/lineedits/window.cpp 8
+ \snippet widgets/lineedits/window.cpp 8
The slots respond to signals emitted when the comboboxes are changed by the
user.
When the combobox for the \uicontrol{Echo} group box is changed, the \c echoChanged()
slot is called:
- \snippet widgets/widgets/lineedits/window.cpp 9
+ \snippet widgets/lineedits/window.cpp 9
The slot updates the line edit in the same group box to use an echo mode that
corresponds to the entry described in the combobox.
When the combobox for the \uicontrol{Validator} group box is changed, the
\c validatorChanged() slot is called:
- \snippet widgets/widgets/lineedits/window.cpp 10
+ \snippet widgets/lineedits/window.cpp 10
The slot either creates a new validator for the line edit to use, or it removes
the validator in use by calling QLineEdit::setValidator() with a zero pointer.
When the combobox for the \uicontrol{Alignment} group box is changed, the
\c alignmentChanged() slot is called:
- \snippet widgets/widgets/lineedits/window.cpp 11
+ \snippet widgets/lineedits/window.cpp 11
This changes the way that text is displayed in the line edit to correspond with
the description selected in the combobox.
The \c inputMaskChanged() slot handles changes to the combobox in the
\uicontrol{Input Mask} group box:
- \snippet widgets/widgets/lineedits/window.cpp 12
+ \snippet widgets/lineedits/window.cpp 12
Each entry in the relevant combobox is associated with an input mask. We set
a new mask by calling the QLineEdit::setMask() function with a suitable string;
The \c accessChanged() slot handles changes to the combobox in the
\uicontrol{Access} group box:
- \snippet widgets/widgets/lineedits/window.cpp 13
+ \snippet widgets/lineedits/window.cpp 13
Here, we simply associate the \uicontrol{False} and \uicontrol{True} entries in the combobox
with \c false and \c true values to be passed to QLineEdit::setReadOnly(). This
****************************************************************************/
/*!
- \example widgets/widgets/movie
+ \example widgets/movie
\title Movie Example
The Movie example demonstrates how to use QMovie and QLabel to
****************************************************************************/
/*!
- \example widgets/widgets/scribble
+ \example widgets/scribble
\title Scribble Example
The Scribble example shows how to reimplement some of QWidget's
\section1 ScribbleArea Class Definition
- \snippet widgets/widgets/scribble/scribblearea.h 0
+ \snippet widgets/scribble/scribblearea.h 0
The \c ScribbleArea class inherits from QWidget. We reimplement
the \c mousePressEvent(), \c mouseMoveEvent() and \c
\section1 ScribbleArea Class Implementation
- \snippet widgets/widgets/scribble/scribblearea.cpp 0
+ \snippet widgets/scribble/scribblearea.cpp 0
In the constructor, we set the Qt::WA_StaticContents
attribute for the widget, indicating that the widget contents are
for widgets whose contents are static and rooted to the top-left
corner.
- \snippet widgets/widgets/scribble/scribblearea.cpp 1
- \snippet widgets/widgets/scribble/scribblearea.cpp 2
+ \snippet widgets/scribble/scribblearea.cpp 1
+ \snippet widgets/scribble/scribblearea.cpp 2
In the \c openImage() function, we load the given image. Then we
resize the loaded QImage to be at least as large as the widget in
we set the \c image member variable to be the loaded image. At
the end, we call QWidget::update() to schedule a repaint.
- \snippet widgets/widgets/scribble/scribblearea.cpp 3
- \snippet widgets/widgets/scribble/scribblearea.cpp 4
+ \snippet widgets/scribble/scribblearea.cpp 3
+ \snippet widgets/scribble/scribblearea.cpp 4
The \c saveImage() function creates a QImage object that covers
only the visible section of the actual \c image and saves it using
scribble area's \c modified variable to \c false, because there is
no unsaved data.
- \snippet widgets/widgets/scribble/scribblearea.cpp 5
- \snippet widgets/widgets/scribble/scribblearea.cpp 6
+ \snippet widgets/scribble/scribblearea.cpp 5
+ \snippet widgets/scribble/scribblearea.cpp 6
\codeline
- \snippet widgets/widgets/scribble/scribblearea.cpp 7
- \snippet widgets/widgets/scribble/scribblearea.cpp 8
+ \snippet widgets/scribble/scribblearea.cpp 7
+ \snippet widgets/scribble/scribblearea.cpp 8
The \c setPenColor() and \c setPenWidth() functions set the
current pen color and width. These values will be used for future
drawing operations.
- \snippet widgets/widgets/scribble/scribblearea.cpp 9
- \snippet widgets/widgets/scribble/scribblearea.cpp 10
+ \snippet widgets/scribble/scribblearea.cpp 9
+ \snippet widgets/scribble/scribblearea.cpp 10
The public \c clearImage() slot clears the image displayed in the
scribble area. We simply fill the entire image with white, which
corresponds to RGB value (255, 255, 255). As usual when we modify
the image, we set \c modified to \c true and schedule a repaint.
- \snippet widgets/widgets/scribble/scribblearea.cpp 11
- \snippet widgets/widgets/scribble/scribblearea.cpp 12
+ \snippet widgets/scribble/scribblearea.cpp 11
+ \snippet widgets/scribble/scribblearea.cpp 12
For mouse press and mouse release events, we use the
QMouseEvent::button() function to find out which button caused
releases the button, we call the private \c drawLineTo() function
to draw.
- \snippet widgets/widgets/scribble/scribblearea.cpp 13
- \snippet widgets/widgets/scribble/scribblearea.cpp 14
+ \snippet widgets/scribble/scribblearea.cpp 13
+ \snippet widgets/scribble/scribblearea.cpp 14
In the reimplementation of the \l
{QWidget::paintEvent()}{paintEvent()} function, we simply create
QWidget into a QImage again, we might lose some information.
\endlist
- \snippet widgets/widgets/scribble/scribblearea.cpp 15
- \snippet widgets/widgets/scribble/scribblearea.cpp 16
+ \snippet widgets/scribble/scribblearea.cpp 15
+ \snippet widgets/scribble/scribblearea.cpp 16
When the user starts the Scribble application, a resize event is
generated and an image is created and displayed in the scribble
would be very inefficient). But when the main window becomes
larger than this initial size, the image needs to be resized.
- \snippet widgets/widgets/scribble/scribblearea.cpp 17
- \snippet widgets/widgets/scribble/scribblearea.cpp 18
+ \snippet widgets/scribble/scribblearea.cpp 17
+ \snippet widgets/scribble/scribblearea.cpp 18
In \c drawLineTo(), we draw a line from the point where the mouse
was located when the last mouse press or mouse move occurred, we
inside the scribble are needs updating, to avoid a complete
repaint of the widget.
- \snippet widgets/widgets/scribble/scribblearea.cpp 19
- \snippet widgets/widgets/scribble/scribblearea.cpp 20
+ \snippet widgets/scribble/scribblearea.cpp 19
+ \snippet widgets/scribble/scribblearea.cpp 20
QImage has no nice API for resizing an image. There's a
QImage::copy() function that could do the trick, but when used to
Printing is handled by the \c print() slot:
- \snippet widgets/widgets/scribble/scribblearea.cpp 21
+ \snippet widgets/scribble/scribblearea.cpp 21
We construct a high resolution QPrinter object for the required
output format, using a QPrintDialog to ask the user to specify a
If the dialog is accepted, we perform the task of printing to the paint
device:
- \snippet widgets/widgets/scribble/scribblearea.cpp 22
+ \snippet widgets/scribble/scribblearea.cpp 22
Printing an image to a file in this way is simply a matter of
painting onto the QPrinter. We scale the image to fit within the
\section1 MainWindow Class Definition
- \snippet widgets/widgets/scribble/mainwindow.h 0
+ \snippet widgets/scribble/mainwindow.h 0
The \c MainWindow class inherits from QMainWindow. We reimplement
the \l{QWidget::closeEvent()}{closeEvent()} handler from QWidget.
\section1 MainWindow Class Implementation
- \snippet widgets/widgets/scribble/mainwindow.cpp 0
+ \snippet widgets/scribble/mainwindow.cpp 0
In the constructor, we create a scribble area which we make the
central widget of the \c MainWindow widget. Then we create the
associated actions and menus.
- \snippet widgets/widgets/scribble/mainwindow.cpp 1
- \snippet widgets/widgets/scribble/mainwindow.cpp 2
+ \snippet widgets/scribble/mainwindow.cpp 1
+ \snippet widgets/scribble/mainwindow.cpp 2
Close events are sent to widgets that the users want to close,
usually by clicking \uicontrol{File|Exit} or by clicking the \uicontrol X
\c maybeSave() returns false, the user clicked \uicontrol Cancel, so we
"ignore" the event, leaving the application unaffected by it.
- \snippet widgets/widgets/scribble/mainwindow.cpp 3
- \snippet widgets/widgets/scribble/mainwindow.cpp 4
+ \snippet widgets/scribble/mainwindow.cpp 3
+ \snippet widgets/scribble/mainwindow.cpp 4
In the \c open() slot we first give the user the opportunity to
save any modifications to the currently displayed image, before a
new image is loaded into the scribble area. Then we ask the user
to choose a file and we load the file in the \c ScribbleArea.
- \snippet widgets/widgets/scribble/mainwindow.cpp 5
- \snippet widgets/widgets/scribble/mainwindow.cpp 6
+ \snippet widgets/scribble/mainwindow.cpp 5
+ \snippet widgets/scribble/mainwindow.cpp 6
The \c save() slot is called when the users choose the \uicontrol {Save
As} menu entry, and then choose an entry from the format menu. The
Now that we know the format, we call the private \c saveFile()
function to save the currently displayed image.
- \snippet widgets/widgets/scribble/mainwindow.cpp 7
- \snippet widgets/widgets/scribble/mainwindow.cpp 8
+ \snippet widgets/scribble/mainwindow.cpp 7
+ \snippet widgets/scribble/mainwindow.cpp 8
We use the \c penColor() slot to retrieve a new color from the
user with a QColorDialog. If the user chooses a new color, we
make it the scribble area's color.
- \snippet widgets/widgets/scribble/mainwindow.cpp 9
- \snippet widgets/widgets/scribble/mainwindow.cpp 10
+ \snippet widgets/scribble/mainwindow.cpp 9
+ \snippet widgets/scribble/mainwindow.cpp 10
To retrieve a new pen width in the \c penWidth() slot, we use
QInputDialog. The QInputDialog class provides a simple
The boolean \c ok variable will be set to \c true if the user
clicked \uicontrol OK and to \c false if the user pressed \uicontrol Cancel.
- \snippet widgets/widgets/scribble/mainwindow.cpp 11
- \snippet widgets/widgets/scribble/mainwindow.cpp 12
+ \snippet widgets/scribble/mainwindow.cpp 11
+ \snippet widgets/scribble/mainwindow.cpp 12
We implement the \c about() slot to create a message box
describing what the example is designed to show.
- \snippet widgets/widgets/scribble/mainwindow.cpp 13
- \snippet widgets/widgets/scribble/mainwindow.cpp 14
+ \snippet widgets/scribble/mainwindow.cpp 13
+ \snippet widgets/scribble/mainwindow.cpp 14
In the \c createAction() function we create the actions
representing the menu entries and connect them to the appropriate
deduced the file format from the action's text, by truncating the
"...", but that would have been inelegant.
- \snippet widgets/widgets/scribble/mainwindow.cpp 15
- \snippet widgets/widgets/scribble/mainwindow.cpp 16
+ \snippet widgets/scribble/mainwindow.cpp 15
+ \snippet widgets/scribble/mainwindow.cpp 16
In the \c createMenu() function, we add the previously created
format actions to the \c saveAsMenu. Then we add the rest of the
{MainWindow}'s menu bar, which we retrieve using the
QMainWindow::menuBar() function.
- \snippet widgets/widgets/scribble/mainwindow.cpp 17
- \snippet widgets/widgets/scribble/mainwindow.cpp 18
+ \snippet widgets/scribble/mainwindow.cpp 17
+ \snippet widgets/scribble/mainwindow.cpp 18
In \c mayBeSave(), we check if there are any unsaved changes. If
there are any, we use QMessageBox to give the user a warning that
The \c maybeSave() function returns \c false if the user clicks
\uicontrol Cancel; otherwise it returns \c true.
- \snippet widgets/widgets/scribble/mainwindow.cpp 19
- \snippet widgets/widgets/scribble/mainwindow.cpp 20
+ \snippet widgets/scribble/mainwindow.cpp 19
+ \snippet widgets/scribble/mainwindow.cpp 20
In \c saveFile(), we pop up a file dialog with a file name
suggestion. The static QFileDialog::getSaveFileName() function
****************************************************************************/
/*!
- \example widgets/widgets/shapedclock
+ \example widgets/shapedclock
\title Shaped Clock Example
The Shaped Clock example shows how to apply a widget mask to a top-level
\l{Analog Clock Example}{Analog Clock} example. The whole class definition is
presented below:
- \snippet widgets/widgets/shapedclock/shapedclock.h 0
+ \snippet widgets/shapedclock/shapedclock.h 0
The \l{QWidget::paintEvent()}{paintEvent()} implementation is the same as that found
in the \c AnalogClock class. We implement \l{QWidget::sizeHint()}{sizeHint()}
The \c ShapedClock constructor performs many of the same tasks as the \c AnalogClock
constructor. We set up a timer and connect it to the widget's update() slot:
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 0
+ \snippet widgets/shapedclock/shapedclock.cpp 0
We inform the window manager that the widget is not to be decorated with a window
frame by setting the Qt::FramelessWindowHint flag on the widget. As a result, we need
Mouse button events are delivered to the \c mousePressEvent() handler:
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 1
+ \snippet widgets/shapedclock/shapedclock.cpp 1
If the left mouse button is pressed over the widget, we record the displacement in
global (screen) coordinates between the top-left position of the widget's frame (even
The \c mouseMoveEvent() handler is called if the mouse is moved over the widget.
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 2
+ \snippet widgets/shapedclock/shapedclock.cpp 2
If the left button is held down while the mouse is moved, the top-left corner of the
widget is moved to the point given by subtracting the \c dragPosition from the current
\l{Analog Clock Example}{Analog Clock} example for a description of the process used
to render the clock.
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 3
+ \snippet widgets/shapedclock/shapedclock.cpp 3
In the \c resizeEvent() handler, we re-use some of the code from the \c paintEvent()
to determine the region of the widget that is visible to the user:
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 4
+ \snippet widgets/shapedclock/shapedclock.cpp 4
Since the clock face is a circle drawn in the center of the widget, this is the region
we use as the mask.
Finally, we implement the \c sizeHint() for the widget so that it is given a reasonable
default size when it is first shown:
- \snippet widgets/widgets/shapedclock/shapedclock.cpp 5
+ \snippet widgets/shapedclock/shapedclock.cpp 5
\section1 Notes on Widget Masks
****************************************************************************/
/*!
- \example widgets/widgets/sliders
+ \example widgets/sliders
\title Sliders Example
Qt provides three types of slider-like widgets: QSlider,
\section1 Window Class Definition
- \snippet widgets/widgets/sliders/window.h 0
+ \snippet widgets/sliders/window.h 0
The \c Window class inherits from QWidget. It displays the slider
widgets and allows the user to set their minimum, maximum and
\section1 Window Class Implementation
- \snippet widgets/widgets/sliders/window.cpp 0
+ \snippet widgets/sliders/window.cpp 0
In the constructor we first create the two \c SlidersGroup
widgets that display the slider widgets horizontally and
widgets. The rest of the controlling mechanisms is implemented by
the same function call.
- \snippet widgets/widgets/sliders/window.cpp 1
- \snippet widgets/widgets/sliders/window.cpp 2
+ \snippet widgets/sliders/window.cpp 1
+ \snippet widgets/sliders/window.cpp 2
Then we connect the \c horizontalSliders, \c verticalSliders and
\c valueSpinBox to each other, so that the slider widgets and the
minimum and maximum values propagate through the connections we
created with \c createControls().
- \snippet widgets/widgets/sliders/window.cpp 3
- \snippet widgets/widgets/sliders/window.cpp 4
+ \snippet widgets/sliders/window.cpp 3
+ \snippet widgets/sliders/window.cpp 4
In the private \c createControls() function, we let a QGroupBox
(\c controlsGroup) display the control widgets. A group box can
bindings are inverted by default: \uicontrol PageDown increases the
current value, and \uicontrol PageUp decreases it.
- \snippet widgets/widgets/sliders/window.cpp 5
- \snippet widgets/widgets/sliders/window.cpp 6
+ \snippet widgets/sliders/window.cpp 5
+ \snippet widgets/sliders/window.cpp 6
Then we create the spin boxes. QSpinBox allows the user to choose
a value by clicking the up and down buttons or pressing the \uicontrol
a list of options to the user in a way that takes up the minimum
amount of screen space.
- \snippet widgets/widgets/sliders/window.cpp 7
- \snippet widgets/widgets/sliders/window.cpp 8
+ \snippet widgets/sliders/window.cpp 7
+ \snippet widgets/sliders/window.cpp 8
We synchronize the behavior of the control widgets and the slider
widgets through their signals and slots. We connect each control
\section1 SlidersGroup Class Definition
- \snippet widgets/widgets/sliders/slidersgroup.h 0
+ \snippet widgets/sliders/slidersgroup.h 0
The \c SlidersGroup class inherits from QGroupBox. It provides a
frame and a title, and contains a QSlider, a QScrollBar and a
\section1 SlidersGroup Class Implementation
- \snippet widgets/widgets/sliders/slidersgroup.cpp 0
+ \snippet widgets/sliders/slidersgroup.cpp 0
First we create the slider-like widgets with the appropriate
properties. In particular we set the focus policy for each
Then we connect the widgets with each other, so that they will
stay synchronized when the current value of one of them changes.
- \snippet widgets/widgets/sliders/slidersgroup.cpp 1
- \snippet widgets/widgets/sliders/slidersgroup.cpp 2
+ \snippet widgets/sliders/slidersgroup.cpp 1
+ \snippet widgets/sliders/slidersgroup.cpp 2
We connect \c {dial}'s \c valueChanged() signal to the
\c{SlidersGroup}'s \c valueChanged() signal, to notify the other
widgets in the application (i.e., the control widgets) of the
changed value.
- \snippet widgets/widgets/sliders/slidersgroup.cpp 3
+ \snippet widgets/sliders/slidersgroup.cpp 3
\codeline
- \snippet widgets/widgets/sliders/slidersgroup.cpp 4
+ \snippet widgets/sliders/slidersgroup.cpp 4
Finally, depending on the \l {Qt::Orientation}{orientation} given
at the time of construction, we choose and create the layout for
the slider widgets within the group box.
- \snippet widgets/widgets/sliders/slidersgroup.cpp 5
- \snippet widgets/widgets/sliders/slidersgroup.cpp 6
+ \snippet widgets/sliders/slidersgroup.cpp 5
+ \snippet widgets/sliders/slidersgroup.cpp 6
The \c setValue() slot sets the value of the QSlider. We don't
need to explicitly call
\l{QAbstractSlider::valueChanged()}{valueChanged()} signal when
its value changes, triggering a domino effect.
- \snippet widgets/widgets/sliders/slidersgroup.cpp 7
- \snippet widgets/widgets/sliders/slidersgroup.cpp 8
+ \snippet widgets/sliders/slidersgroup.cpp 7
+ \snippet widgets/sliders/slidersgroup.cpp 8
\codeline
- \snippet widgets/widgets/sliders/slidersgroup.cpp 9
- \snippet widgets/widgets/sliders/slidersgroup.cpp 10
+ \snippet widgets/sliders/slidersgroup.cpp 9
+ \snippet widgets/sliders/slidersgroup.cpp 10
The \c setMinimum() and \c setMaximum() slots are used by the \c
Window class to set the range of the QSlider, QScrollBar, and
QDial widgets.
- \snippet widgets/widgets/sliders/slidersgroup.cpp 11
- \snippet widgets/widgets/sliders/slidersgroup.cpp 12
+ \snippet widgets/sliders/slidersgroup.cpp 11
+ \snippet widgets/sliders/slidersgroup.cpp 12
\codeline
- \snippet widgets/widgets/sliders/slidersgroup.cpp 13
- \snippet widgets/widgets/sliders/slidersgroup.cpp 14
+ \snippet widgets/sliders/slidersgroup.cpp 13
+ \snippet widgets/sliders/slidersgroup.cpp 14
The \c invertAppearance() and \c invertKeyBindings() slots
control the child widgets'
****************************************************************************/
/*!
- \example widgets/widgets/spinboxes
+ \example widgets/spinboxes
\title Spin Boxes Example
The Spin Boxes example shows how to use the many different types of spin boxes
The \c Window class inherits QWidget and contains two slots that are used
to provide interactive features:
- \snippet widgets/widgets/spinboxes/window.h 0
+ \snippet widgets/spinboxes/window.h 0
The private functions are used to set up each type of spin box in the window.
We use member variables to keep track of various widgets so that they can
The constructor simply calls private functions to set up the different types
of spin box used in the example, and places each group in a layout:
- \snippet widgets/widgets/spinboxes/window.cpp 0
+ \snippet widgets/spinboxes/window.cpp 0
We use the layout to manage the arrangement of the window's child widgets,
and change the window title.
QSpinBox widgets inside it with descriptive labels to indicate the types of
input they expect.
- \snippet widgets/widgets/spinboxes/window.cpp 1
+ \snippet widgets/spinboxes/window.cpp 1
The first spin box shows the simplest way to use QSpinBox. It accepts values
from -20 to 20, the current value can be increased or decreased by 1 with
The second spin box uses a larger step size and displays a suffix to
provide more information about the type of data the number represents:
- \snippet widgets/widgets/spinboxes/window.cpp 2
+ \snippet widgets/spinboxes/window.cpp 2
This spin box also displays a
\l{QAbstractSpinBox::specialValueText}{special value} instead of the minimum
The third spin box shows how a prefix can be used:
- \snippet widgets/widgets/spinboxes/window.cpp 4
+ \snippet widgets/spinboxes/window.cpp 4
For simplicity, we show a spin box with a prefix and no suffix. It is also
possible to use both at the same time.
- \snippet widgets/widgets/spinboxes/window.cpp 5
+ \snippet widgets/spinboxes/window.cpp 5
The rest of the function sets up a layout for the group box and places each
of the widgets inside it.
The \c createDateTimeEdits() function constructs another group box with a
selection of spin boxes used for editing dates and times.
- \snippet widgets/widgets/spinboxes/window.cpp 6
+ \snippet widgets/spinboxes/window.cpp 6
The first spin box is a QDateEdit widget that is able to accept dates
within a given range specified using QDate values. The arrow buttons and
The second spin box is a QTimeEdit widget:
- \snippet widgets/widgets/spinboxes/window.cpp 7
+ \snippet widgets/spinboxes/window.cpp 7
Acceptable values for the time are defined using QTime values.
times for a meeting. These widgets will be updated when the user changes a
format string.
- \snippet widgets/widgets/spinboxes/window.cpp 8
+ \snippet widgets/spinboxes/window.cpp 8
The format string used for the date time editor, which is also shown in the
string displayed by the label, is chosen from a set of strings in a combobox:
- \snippet widgets/widgets/spinboxes/window.cpp 9
+ \snippet widgets/spinboxes/window.cpp 9
\codeline
- \snippet widgets/widgets/spinboxes/window.cpp 10
+ \snippet widgets/spinboxes/window.cpp 10
A signal from this combobox is connected to a slot in the \c Window class
(shown later).
- \snippet widgets/widgets/spinboxes/window.cpp 11
+ \snippet widgets/spinboxes/window.cpp 11
Each child widget of the group box in placed in a layout.
format string in the combobox. The display format for the QDateTimeEdit
widget is set using the raw string passed by the signal:
- \snippet widgets/widgets/spinboxes/window.cpp 12
+ \snippet widgets/spinboxes/window.cpp 12
Depending on the visible sections in the widget, we set a new date or time
range, and update the associated label to provide relevant information for
the user:
- \snippet widgets/widgets/spinboxes/window.cpp 13
+ \snippet widgets/spinboxes/window.cpp 13
When the format string is changed, there will be an appropriate label and
entry widget for dates, times, or both types of input.
The \c createDoubleSpinBoxes() function constructs three spin boxes that are
used to input double-precision floating point numbers:
- \snippet widgets/widgets/spinboxes/window.cpp 14
+ \snippet widgets/spinboxes/window.cpp 14
Before the QDoubleSpinBox widgets are constructed, we create a spin box to
control how many decimal places they show. By default, only two decimal places
same range, step size, and default value as the first spin box in the
\c createSpinBoxes() function:
- \snippet widgets/widgets/spinboxes/window.cpp 15
+ \snippet widgets/spinboxes/window.cpp 15
However, this spin box also allows non-integer values to be entered.
The second spin box displays a suffix and shows a special value instead
of the minimum value:
- \snippet widgets/widgets/spinboxes/window.cpp 16
+ \snippet widgets/spinboxes/window.cpp 16
The third spin box displays a prefix instead of a suffix:
- \snippet widgets/widgets/spinboxes/window.cpp 17
+ \snippet widgets/spinboxes/window.cpp 17
We connect the QSpinBox widget that specifies the precision to a slot in
the \c Window class.
- \snippet widgets/widgets/spinboxes/window.cpp 18
+ \snippet widgets/spinboxes/window.cpp 18
The rest of the function places each of the widgets into a layout for the
group box.
The \c changePrecision() slot is called when the user changes the value in
the precision spin box:
- \snippet widgets/widgets/spinboxes/window.cpp 19
+ \snippet widgets/spinboxes/window.cpp 19
This function simply uses the integer supplied by the signal to specify the
number of decimal places in each of the QDoubleSpinBox widgets. Each one
****************************************************************************/
/*!
- \example widgets/widgets/styles
+ \example widgets/styles
\title Styles Example
The Styles example illustrates how to create custom widget
Here's the definition of the \c NorwegianWoodStyle class:
- \snippet widgets/widgets/styles/norwegianwoodstyle.h 0
+ \snippet widgets/styles/norwegianwoodstyle.h 0
The public functions are all declared in QStyle (QMotifStyle's
grandparent class) and reimplemented here to override the Motif
We will now review the implementation of the \c
NorwegianWoodStyle class.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 0
+ \snippet widgets/styles/norwegianwoodstyle.cpp 0
The \c polish() function is reimplemented from QStyle. It takes a
QPalette as a reference and adapts the palette to fit the style.
buttonImage. This image will be used for filling buttons that the
user is holding down.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 1
+ \snippet widgets/styles/norwegianwoodstyle.cpp 1
We initialize the palette. Palettes have various
\l{QPalette::ColorRole}{color roles}, such as QPalette::Base
Let's move on to the other functions reimplemented from
QMotifStyle:
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 3
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 4
+ \snippet widgets/styles/norwegianwoodstyle.cpp 3
+ \snippet widgets/styles/norwegianwoodstyle.cpp 4
This QStyle::polish() overload is called once on every widget
drawn using the style. We reimplement it to set the Qt::WA_Hover
render push buttons and comboboxes differently when the mouse
pointer is over them.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 5
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 6
+ \snippet widgets/styles/norwegianwoodstyle.cpp 5
+ \snippet widgets/styles/norwegianwoodstyle.cpp 6
This QStyle::unpolish() overload is called to undo any
modification done to the widget in \c polish(). For simplicity,
widgets (e.g., using a QMap<QWidget *, bool>) and restore it in
\c unpolish().
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 7
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 8
+ \snippet widgets/styles/norwegianwoodstyle.cpp 7
+ \snippet widgets/styles/norwegianwoodstyle.cpp 8
The \l{QStyle::pixelMetric()}{pixelMetric()} function returns the
size in pixels for a certain user interface element. By
For all other QStyle::PixelMetric elements, we use the Motif
settings.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 9
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 10
+ \snippet widgets/styles/norwegianwoodstyle.cpp 9
+ \snippet widgets/styles/norwegianwoodstyle.cpp 10
The \l{QStyle::styleHint()}{styleHint()} function returns some
hints to widgets or to the base style (in our case QMotifStyle)
QStyle::SH_EtchDisabledText hint, meaning that disabled text is
rendered with an embossed look (as QWindowsStyle does).
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 11
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 12
+ \snippet widgets/styles/norwegianwoodstyle.cpp 11
+ \snippet widgets/styles/norwegianwoodstyle.cpp 12
The \l{QStyle::drawPrimitive()}{drawPrimitive()} function is
called by Qt widgets to draw various fundamental graphical
QStyle::State_MouseOver flag to be set when the mouse is over the
widget.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 13
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 14
+ \snippet widgets/styles/norwegianwoodstyle.cpp 13
+ \snippet widgets/styles/norwegianwoodstyle.cpp 14
The \c roundRect variable is a QPainterPath. A QPainterPath is is
a vectorial specification of a shape. Any shape (rectangle,
\c roundRectPath() function is a private function; we will come
back to it later.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 15
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 16
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 17
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 18
+ \snippet widgets/styles/norwegianwoodstyle.cpp 15
+ \snippet widgets/styles/norwegianwoodstyle.cpp 16
+ \snippet widgets/styles/norwegianwoodstyle.cpp 17
+ \snippet widgets/styles/norwegianwoodstyle.cpp 18
We define two variables, \c brush and \c darker, and initialize
them based on the state of the button:
performs a dynamic cast; if \c option is not a
QStyleOptionButton, qstyleoption_cast() returns a null pointer.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 19
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 20
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 21
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 22
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 23
+ \snippet widgets/styles/norwegianwoodstyle.cpp 19
+ \snippet widgets/styles/norwegianwoodstyle.cpp 20
+ \snippet widgets/styles/norwegianwoodstyle.cpp 21
+ \snippet widgets/styles/norwegianwoodstyle.cpp 22
+ \snippet widgets/styles/norwegianwoodstyle.cpp 23
We turn on antialiasing on QPainter. Antialiasing is a technique
that reduces the visual distortion that occurs when the edges of
semi-transparent black color (a black color with an alpha channel
of 63) to make the area darker if \c darker is true.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 24
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 25
+ \snippet widgets/styles/norwegianwoodstyle.cpp 24
+ \snippet widgets/styles/norwegianwoodstyle.cpp 25
Next, we draw the outline. The top-left half of the outline and
the bottom-right half of the outline are drawn using different
\l{QAbstractButton::checked}{checked}, we invert the two
\l{QPen}s to give a sunken look to the button.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 26
+ \snippet widgets/styles/norwegianwoodstyle.cpp 26
We draw the top-left part of the outline by calling
QPainter::drawPath() with an appropriate
pass the \c -reverse command-line option to the application. This
option is recognized by the QApplication constructor.
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 32
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 33
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 34
+ \snippet widgets/styles/norwegianwoodstyle.cpp 32
+ \snippet widgets/styles/norwegianwoodstyle.cpp 33
+ \snippet widgets/styles/norwegianwoodstyle.cpp 34
The bottom-right part of the outline is drawn in a similar
fashion. Then we draw a one-pixel wide outline around the entire
base style. Let's now turn to the other \c NorwegianWoodStyle
member functions:
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 35
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 36
+ \snippet widgets/styles/norwegianwoodstyle.cpp 35
+ \snippet widgets/styles/norwegianwoodstyle.cpp 36
We reimplement QStyle::drawControl() to draw the text on a
QPushButton in a bright color when the button is
QPalette::ButtonText be the same as the QPalette::BrightText
component (unless the widget is disabled).
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 37
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 38
+ \snippet widgets/styles/norwegianwoodstyle.cpp 37
+ \snippet widgets/styles/norwegianwoodstyle.cpp 38
The \c setTexture() function is a private function that sets the
\l{QBrush::texture()}{texture} component of the \l{QBrush}es for
inactive). We used it to initialize the Norwegian Wood palette in
\c polish(QPalette &).
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 39
- \snippet widgets/widgets/styles/norwegianwoodstyle.cpp 40
+ \snippet widgets/styles/norwegianwoodstyle.cpp 39
+ \snippet widgets/styles/norwegianwoodstyle.cpp 40
The \c roundRectPath() function is a private function that
constructs a QPainterPath object for round buttons. The path
class, which contains the most common Qt widgets and allows the
user to change style dynamically. Here's the class definition:
- \snippet widgets/widgets/styles/widgetgallery.h 0
+ \snippet widgets/styles/widgetgallery.h 0
\dots
- \snippet widgets/widgets/styles/widgetgallery.h 1
+ \snippet widgets/styles/widgetgallery.h 1
Here's the \c WidgetGallery constructor:
- \snippet widgets/widgets/styles/widgetgallery.cpp 0
+ \snippet widgets/styles/widgetgallery.cpp 0
We start by creating child widgets. The \uicontrol Style combobox is
initialized with all the styles known to QStyleFactory, in
private functions that set up the various parts of the \c
WidgetGallery.
- \snippet widgets/widgets/styles/widgetgallery.cpp 1
- \snippet widgets/widgets/styles/widgetgallery.cpp 2
+ \snippet widgets/styles/widgetgallery.cpp 1
+ \snippet widgets/styles/widgetgallery.cpp 2
We connect the \uicontrol Style combobox to the \c changeStyle()
private slot, the \uicontrol{Use style's standard palette} check box to
box to the child widgets'
\l{QWidget::setDisabled()}{setDisabled()} slot.
- \snippet widgets/widgets/styles/widgetgallery.cpp 3
- \snippet widgets/widgets/styles/widgetgallery.cpp 4
+ \snippet widgets/styles/widgetgallery.cpp 3
+ \snippet widgets/styles/widgetgallery.cpp 4
Finally, we put the child widgets in layouts.
- \snippet widgets/widgets/styles/widgetgallery.cpp 5
- \snippet widgets/widgets/styles/widgetgallery.cpp 6
+ \snippet widgets/styles/widgetgallery.cpp 5
+ \snippet widgets/styles/widgetgallery.cpp 6
When the user changes the style in the combobox, we call
QApplication::setStyle() to dynamically change the style of the
application.
- \snippet widgets/widgets/styles/widgetgallery.cpp 7
- \snippet widgets/widgets/styles/widgetgallery.cpp 8
+ \snippet widgets/styles/widgetgallery.cpp 7
+ \snippet widgets/styles/widgetgallery.cpp 8
If the user turns the \uicontrol{Use style's standard palette} on, the
current style's \l{QStyle::standardPalette()}{standard palette}
always override the palette with our own palette in \c
NorwegianWoodStyle::polish().
- \snippet widgets/widgets/styles/widgetgallery.cpp 9
- \snippet widgets/widgets/styles/widgetgallery.cpp 10
+ \snippet widgets/styles/widgetgallery.cpp 9
+ \snippet widgets/styles/widgetgallery.cpp 10
The \c advanceProgressBar() slot is called at regular intervals
to advance the progress bar. Since we don't know how long the
We will review \c createProgressBar() in a moment.
- \snippet widgets/widgets/styles/widgetgallery.cpp 11
- \snippet widgets/widgets/styles/widgetgallery.cpp 12
+ \snippet widgets/styles/widgetgallery.cpp 11
+ \snippet widgets/styles/widgetgallery.cpp 12
The \c createTopLeftGroupBox() function creates the QGroupBox
that occupies the top-left corner of the \c WidgetGallery. We
createBottomLeftTabWidget(), and \c createBottomRightGroupBox()
functions, which are very similar.
- \snippet widgets/widgets/styles/widgetgallery.cpp 13
+ \snippet widgets/styles/widgetgallery.cpp 13
In \c createProgressBar(), we create a QProgressBar at the bottom
of the \c WidgetGallery and connect its
****************************************************************************/
/*!
- \example widgets/widgets/stylesheet
+ \example widgets/stylesheet
\title Style Sheet Example
The Style Sheet Example shows how to use style sheets.
****************************************************************************/
/*!
- \example widgets/widgets/tablet
+ \example widgets/tablet
\title Tablet Example
This example shows how to use a Wacom tablet in Qt applications.
The \c MainWindow creates a \c TabletCanvas and sets it as its
center widget.
- \snippet widgets/widgets/tablet/mainwindow.h 0
+ \snippet widgets/tablet/mainwindow.h 0
The QActions let the user select if the tablets pressure and
tilt should change the pen width, color alpha component and color
We start width a look at the constructor \c MainWindow():
- \snippet widgets/widgets/tablet/mainwindow.cpp 0
+ \snippet widgets/tablet/mainwindow.cpp 0
In the constructor we create the canvas, actions, and menus.
We set the canvas as the center widget. We also initialize the
Here is the implementation of \c brushColorAct():
- \snippet widgets/widgets/tablet/mainwindow.cpp 1
+ \snippet widgets/tablet/mainwindow.cpp 1
We let the user pick a color with a QColorDialog. If it is valid,
we set a new drawing color with \c setColor().
Here is the implementation of \c alphaActionTriggered():
- \snippet widgets/widgets/tablet/mainwindow.cpp 2
+ \snippet widgets/tablet/mainwindow.cpp 2
The \c TabletCanvas class supports two ways by which the alpha
channel of the drawing color can be changed: tablet pressure and
Here is the implementation of \c lineWidthActionTriggered():
- \snippet widgets/widgets/tablet/mainwindow.cpp 3
+ \snippet widgets/tablet/mainwindow.cpp 3
We check which action is selected in \c lineWidthGroup, and set
how the canvas should change the drawing line width.
Here is the implementation of \c saturationActionTriggered():
- \snippet widgets/widgets/tablet/mainwindow.cpp 4
+ \snippet widgets/tablet/mainwindow.cpp 4
We check which action is selected in \c colorSaturationGroup, and
set how the canvas should change the color saturation of the
Here is the implementation of \c saveAct():
- \snippet widgets/widgets/tablet/mainwindow.cpp 5
+ \snippet widgets/tablet/mainwindow.cpp 5
We use the QFileDialog to let the user select a file to save the
drawing in. It is the \c TabletCanvas that save the drawing, so we
Here is the implementation of \c loadAct():
- \snippet widgets/widgets/tablet/mainwindow.cpp 6
+ \snippet widgets/tablet/mainwindow.cpp 6
We let the user select the image file to be opened with
a QFileDialog; we then ask the canvas to load the image with \c
Here is the implementation of \c aboutAct():
- \snippet widgets/widgets/tablet/mainwindow.cpp 7
+ \snippet widgets/tablet/mainwindow.cpp 7
We show a message box with a short description of the example.
Here is the implementation of \c createActions:
- \snippet widgets/widgets/tablet/mainwindow.cpp 8
+ \snippet widgets/tablet/mainwindow.cpp 8
\dots
- \snippet widgets/widgets/tablet/mainwindow.cpp 9
+ \snippet widgets/tablet/mainwindow.cpp 9
We want the user to be able to choose if the drawing color's
alpha component should be changed by the tablet pressure or tilt.
triggered() signal is emitted when an action is checked.
\dots
- \snippet widgets/widgets/tablet/mainwindow.cpp 10
+ \snippet widgets/tablet/mainwindow.cpp 10
Here is the implementation of \c createMenus():
- \snippet widgets/widgets/tablet/mainwindow.cpp 11
+ \snippet widgets/tablet/mainwindow.cpp 11
We create the menus of the example and add the actions to them.
The \c TabletCanvas class provides a surface on which the
user can draw with a tablet.
- \snippet widgets/widgets/tablet/tabletcanvas.h 0
+ \snippet widgets/tablet/tabletcanvas.h 0
The canvas can change the alpha channel, color saturation,
and line width of the drawing. We have one enum for each of
We start with a look at the constructor:
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 0
+ \snippet widgets/tablet/tabletcanvas.cpp 0
In the constructor we initialize our class variables. We need
to draw the background of our pixmap, as the default is gray.
Here is the implementation of \c saveImage():
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 1
+ \snippet widgets/tablet/tabletcanvas.cpp 1
QPixmap implements functionality to save itself to disk, so we
simply call \l{QPixmap::}{save()}.
Here is the implementation of \c loadImage():
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 2
+ \snippet widgets/tablet/tabletcanvas.cpp 2
We simply call \l{QPixmap::}{load()}, which loads the image in \a
file.
Here is the implementation of \c tabletEvent():
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 3
+ \snippet widgets/tablet/tabletcanvas.cpp 3
We get three kind of events to this function: TabletPress,
TabletRelease, and TabletMove, which is generated when a device
Here is the implementation of \c paintEvent():
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 4
+ \snippet widgets/tablet/tabletcanvas.cpp 4
We simply draw the pixmap to the top left of the widget.
Here is the implementation of \c paintPixmap():
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 5
+ \snippet widgets/tablet/tabletcanvas.cpp 5
In this function we draw on the pixmap based on the movement of the
device. If the device used on the tablet is a stylus we want to draw a
density; we select the style based on the tangential pressure in
\c brushPattern().
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 6
+ \snippet widgets/tablet/tabletcanvas.cpp 6
We return a brush style with a point density that increases with
the tangential pressure.
colorSaturationType, and \c myColor. We will examine the code to
set up \c myBrush and \c myPen for each of these variables:
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 7
+ \snippet widgets/tablet/tabletcanvas.cpp 7
We fetch the current drawingcolor's hue, saturation, value,
and alpha values. \c hValue and \c vValue are set to the
is between the device and the perpendicular of the tablet (see
QTabletEvent for an illustration).
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 8
+ \snippet widgets/tablet/tabletcanvas.cpp 8
The alpha channel of QColor is given as a number between 0
and 255 where 0 is transparent and 255 is opaque.
the tablet. We select the largest of the vertical and horizontal
tilt value.
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 9
+ \snippet widgets/tablet/tabletcanvas.cpp 9
The colorsaturation is given as a number between 0 and 255. It is
set with \l{QColor::}{setHsv()}. We can set the tilt values
directly, but must multiply the pressure to a number between 0 and
255.
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 10
+ \snippet widgets/tablet/tabletcanvas.cpp 10
The width of the pen increases with the pressure. When the pen
width is controlled with the tilt we let the width increse with
the angle between the device and the perpendicular of the tablet.
- \snippet widgets/widgets/tablet/tabletcanvas.cpp 11
+ \snippet widgets/tablet/tabletcanvas.cpp 11
We finally check whether the pointer is the stylus or the eraser.
If it is the eraser, we set the color to the background color of
We inherit QApplication in this class because we want to
reimplement the \l{QApplication::}{event()} function.
- \snippet widgets/widgets/tablet/tabletapplication.h 0
+ \snippet widgets/tablet/tabletapplication.h 0
We keep a \c TabletCanvas we send the device type of the events we
handle in the \c event() function to. The TabletEnterProximity
Here is the implementation of \c event():
- \snippet widgets/widgets/tablet/tabletapplication.cpp 0
+ \snippet widgets/tablet/tabletapplication.cpp 0
We use this function to handle the TabletEnterProximity and
TabletLeaveProximity events, which is generated when a device
Here is the examples \c main() function:
- \snippet widgets/widgets/tablet/main.cpp 0
+ \snippet widgets/tablet/main.cpp 0
In the \c main() function we create a \c MainWinow and display it
as a top level window. We use the \c TabletApplication class. We
****************************************************************************/
/*!
- \example widgets/widgets/tetrix
+ \example widgets/tetrix
\title Tetrix Example
The Tetrix example is a Qt version of the classic Tetrix game.
The \c TetrixWindow class is used to display the game information and contains
the playing area:
- \snippet widgets/widgets/tetrix/tetrixwindow.h 0
+ \snippet widgets/tetrix/tetrixwindow.h 0
We use private member variables for the board, various display widgets, and
buttons to allow the user to start a new game, pause the current game, and quit.
The constructor sets up the user interface elements for the game:
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 0
+ \snippet widgets/tetrix/tetrixwindow.cpp 0
We begin by constructing a \c TetrixBoard instance for the playing area and a
label that shows the next piece to be dropped into the playing area; the label
lines removed. These initially show default values, and will be filled in
when a game begins:
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 1
+ \snippet widgets/tetrix/tetrixwindow.cpp 1
Three buttons with shortcuts are constructed so that the user can start a
new game, pause the current game, and quit the application:
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 2
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 3
+ \snippet widgets/tetrix/tetrixwindow.cpp 2
+ \snippet widgets/tetrix/tetrixwindow.cpp 3
These buttons are configured so that they never receive the keyboard focus;
we want the keyboard focus to remain with the \c TetrixBoard instance so that
and \uicontrol{Pause} buttons to the board, and from the \uicontrol{Quit} button to the
application's \l{QApplication::}{quit()} slot.
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 4
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 5
+ \snippet widgets/tetrix/tetrixwindow.cpp 4
+ \snippet widgets/tetrix/tetrixwindow.cpp 5
Signals from the board are also connected to the LCD widgets for the purpose of
updating the score, number of lives, and lines removed from the playing area.
along with some labels that we create with the \c createLabel() convenience
function:
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 6
+ \snippet widgets/tetrix/tetrixwindow.cpp 6
Finally, we set the grid layout on the widget, give the window a title, and
resize it to an appropriate size.
The \c createLabel() convenience function simply creates a new label on the
heap, gives it an appropriate alignment, and returns it to the caller:
- \snippet widgets/widgets/tetrix/tetrixwindow.cpp 7
+ \snippet widgets/tetrix/tetrixwindow.cpp 7
Since each label will be used in the widget's layout, it will become a child
of the \c TetrixWindow widget and, as a result, it will be deleted when the
playing area, including its shape, position, and the range of positions it can
occupy on the board:
- \snippet widgets/widgets/tetrix/tetrixpiece.h 0
+ \snippet widgets/tetrix/tetrixpiece.h 0
Each shape contains four blocks, and these are defined by the \c coords private
member variable. Additionally, each piece has a high-level description that is
The \c setRandomShape() function is used to select a random shape for a piece:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 0
+ \snippet widgets/tetrix/tetrixpiece.cpp 0
For convenience, it simply chooses a random shape from the \c TetrixShape enum
and calls the \c setShape() function to perform the task of positioning the
The \c setShape() function uses a look-up table of pieces to associate each
shape with an array of block positions:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 1
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 2
+ \snippet widgets/tetrix/tetrixpiece.cpp 1
+ \snippet widgets/tetrix/tetrixpiece.cpp 2
These positions are read from the table into the piece's own array of positions,
and the piece's internal shape information is updated to use the new shape.
The \c minX() and \c maxX() functions return the minimum and maximum horizontal
coordinates occupied by the blocks that make up the piece:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 3
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 4
+ \snippet widgets/tetrix/tetrixpiece.cpp 3
+ \snippet widgets/tetrix/tetrixpiece.cpp 4
Similarly, the \c minY() and \c maxY() functions return the minimum and maximum
vertical coordinates occupied by the blocks:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 5
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 6
+ \snippet widgets/tetrix/tetrixpiece.cpp 5
+ \snippet widgets/tetrix/tetrixpiece.cpp 6
The \c rotatedLeft() function returns a new piece with the same shape as an
existing piece, but rotated counter-clockwise by 90 degrees:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 7
+ \snippet widgets/tetrix/tetrixpiece.cpp 7
Similarly, the \c rotatedRight() function returns a new piece with the same
shape as an existing piece, but rotated clockwise by 90 degrees:
- \snippet widgets/widgets/tetrix/tetrixpiece.cpp 9
+ \snippet widgets/tetrix/tetrixpiece.cpp 9
These last two functions enable each piece to create rotated copies of itself.
The \c TetrixBoard class inherits from QFrame and contains the game logic and display features:
- \snippet widgets/widgets/tetrix/tetrixboard.h 0
+ \snippet widgets/tetrix/tetrixboard.h 0
Apart from the \c setNextPieceLabel() function and the \c start() and \c pause()
public slots, we only provide public functions to reimplement QWidget::sizeHint()
The rest of the functionality is provided by reimplementations of protected event
handlers and private functions:
- \snippet widgets/widgets/tetrix/tetrixboard.h 1
+ \snippet widgets/tetrix/tetrixboard.h 1
The board is composed of a fixed-size array whose elements correspond to
spaces for individual blocks. Each element in the array contains a \c TetrixShape
keyboard input will be received by the widget by using Qt::StrongFocus for the
focus policy, and initialize the game state:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 0
+ \snippet widgets/tetrix/tetrixboard.cpp 0
The first (next) piece is also set up with a random shape.
The \c setNextPieceLabel() function is used to pass in an externally-constructed
label to the board, so that it can be shown alongside the playing area:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 1
+ \snippet widgets/tetrix/tetrixboard.cpp 1
We provide a reasonable size hint and minimum size hint for the board, based on
the size of the space for each block in the playing area:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 2
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 3
+ \snippet widgets/tetrix/tetrixboard.cpp 2
+ \snippet widgets/tetrix/tetrixboard.cpp 3
By using a minimum size hint, we indicate to the layout in the parent widget
that the board should not shrink below a minimum size.
A new game is started when the \c start() slot is called. This resets the
game's state, the player's score and level, and the contents of the board:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 4
+ \snippet widgets/tetrix/tetrixboard.cpp 4
We also emit signals to inform other components of these changes before creating
a new piece that is ready to be dropped into the playing area. We start the
The \c pause() slot is used to temporarily stop the current game by stopping the
internal timer:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 5
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 6
+ \snippet widgets/tetrix/tetrixboard.cpp 5
+ \snippet widgets/tetrix/tetrixboard.cpp 6
We perform checks to ensure that the game can only be paused if it is already
running and not already paused.
calling the base class's implementation of \l{QWidget::}{paintEvent()} before
constructing a QPainter for use on the board:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 7
+ \snippet widgets/tetrix/tetrixboard.cpp 7
Since the board is a subclass of QFrame, we obtain a QRect that covers the area
\e inside the frame decoration before drawing our own content.
For each space on the board that is occupied by a piece, we call the
\c drawSquare() function to draw a block at that position.
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 8
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 9
+ \snippet widgets/tetrix/tetrixboard.cpp 8
+ \snippet widgets/tetrix/tetrixboard.cpp 9
Spaces that are not occupied by blocks are left blank.
Unlike the existing pieces on the board, the current piece is drawn
block-by-block at its current position:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 10
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 11
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 12
+ \snippet widgets/tetrix/tetrixboard.cpp 10
+ \snippet widgets/tetrix/tetrixboard.cpp 11
+ \snippet widgets/tetrix/tetrixboard.cpp 12
The \c keyPressEvent() handler is called whenever the player presses a key while
the \c TetrixBoard widget has the keyboard focus.
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 13
+ \snippet widgets/tetrix/tetrixboard.cpp 13
If there is no current game, the game is running but paused, or if there is no
current shape to control, we simply pass on the event to the base class.
control the current piece and, if so, we call the relevant function to handle
the input:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 14
+ \snippet widgets/tetrix/tetrixboard.cpp 14
In the case where the player presses a key that we are not interested in, we
again pass on the event to the base class's implementation of
instance times out. We need to check that the event we receive corresponds to
our timer. If it does, we can update the board:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 15
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 16
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 17
+ \snippet widgets/tetrix/tetrixboard.cpp 15
+ \snippet widgets/tetrix/tetrixboard.cpp 16
+ \snippet widgets/tetrix/tetrixboard.cpp 17
If a row (or line) has just been filled, we create a new piece and reset the
timer; otherwise we move the current piece down by one row. We let the base
The \c clearBoard() function simply fills the board with the
\c TetrixShape::NoShape value:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 18
+ \snippet widgets/tetrix/tetrixboard.cpp 18
The \c dropDown() function moves the current piece down as far as possible on
the board, either until it is touching the bottom of the playing area or it is
stacked on top of another piece:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 19
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 20
+ \snippet widgets/tetrix/tetrixboard.cpp 19
+ \snippet widgets/tetrix/tetrixboard.cpp 20
The number of rows the piece has dropped is recorded and passed to the
\c pieceDropped() function so that the player's score can be updated.
(line), either when the user presses the \uicontrol{D} key or when the piece is
scheduled to move:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 21
+ \snippet widgets/tetrix/tetrixboard.cpp 21
If the piece cannot drop down by one line, we call the \c pieceDropped() function
with zero as the argument to indicate that it cannot fall any further, and that
and, if no lines have been removed, creating a new piece to replace the current
one:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 22
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 23
+ \snippet widgets/tetrix/tetrixboard.cpp 22
+ \snippet widgets/tetrix/tetrixboard.cpp 23
We call \c removeFullLines() each time a piece has been dropped. This scans
the board from bottom to top, looking for blank spaces on each row.
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 24
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 25
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 26
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 27
+ \snippet widgets/tetrix/tetrixboard.cpp 24
+ \snippet widgets/tetrix/tetrixboard.cpp 25
+ \snippet widgets/tetrix/tetrixboard.cpp 26
+ \snippet widgets/tetrix/tetrixboard.cpp 27
If a row contains no blank spaces, the rows above it are copied down by one row
to compress the stack of pieces, the top row on the board is cleared, and the
number of full lines found is incremented.
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 28
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 29
+ \snippet widgets/tetrix/tetrixboard.cpp 28
+ \snippet widgets/tetrix/tetrixboard.cpp 29
If some lines have been removed, the player's score and the total number of lines
removed are updated. The \c linesRemoved() and \c scoreChanged() signals are
The \c newPiece() function places the next available piece at the top of the
board, and creates a new piece with a random shape:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 30
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 31
+ \snippet widgets/tetrix/tetrixboard.cpp 30
+ \snippet widgets/tetrix/tetrixboard.cpp 31
We place a new piece in the middle of the board at the top. The game is over if
the piece can't move, so we unset its shape to prevent it from being drawn, stop
The \c showNextPiece() function updates the label that shows the next piece to
be dropped:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 32
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 33
+ \snippet widgets/tetrix/tetrixboard.cpp 32
+ \snippet widgets/tetrix/tetrixboard.cpp 33
We draw the piece's component blocks onto a pixmap that is then set on the label.
The \c tryMove() function is used to determine whether a piece can be positioned
at the specified coordinates:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 34
+ \snippet widgets/tetrix/tetrixboard.cpp 34
We examine the spaces on the board that the piece needs to occupy and, if they
are already occupied by other pieces, we return \c false to indicate that the
move has failed.
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 35
+ \snippet widgets/tetrix/tetrixboard.cpp 35
If the piece could be placed on the board at the desired location, we update the
current piece and its position, update the widget, and return \c true to indicate
The \c drawSquare() function draws the blocks (normally squares) that make up
each piece using different colors for pieces with different shapes:
- \snippet widgets/widgets/tetrix/tetrixboard.cpp 36
+ \snippet widgets/tetrix/tetrixboard.cpp 36
We obtain the color to use from a look-up table that relates each shape to an
RGB value, and use the painter provided to draw the block at the specified
****************************************************************************/
/*!
- \example widgets/widgets/tooltips
+ \example widgets/tooltips
\title Tool Tips Example
The Tool Tips example shows how to provide static and dynamic tool
\section1 SortingBox Class Definition
- \snippet widgets/widgets/tooltips/sortingbox.h 0
+ \snippet widgets/tooltips/sortingbox.h 0
The \c SortingBox class inherits QWidget, and it is the Tooltips
application's main widget. We reimplement several of the event
In addition we need three private slots to make the user able to
create new shape items.
- \snippet widgets/widgets/tooltips/sortingbox.h 1
+ \snippet widgets/tooltips/sortingbox.h 1
We also create several private functions: We use the \c
initialItemPosition(), \c initialItemColor() and \c
randomItemPosition() and \c randomItemColor() functions to create
new shape items.
- \snippet widgets/widgets/tooltips/sortingbox.h 2
+ \snippet widgets/tooltips/sortingbox.h 2
We keep all the shape items in a QList, and we keep three
QPainterPath objects holding the shapes of a circle, a square and
\section1 SortingBox Class Implementation
- \snippet widgets/widgets/tooltips/sortingbox.cpp 0
+ \snippet widgets/tooltips/sortingbox.cpp 0
In the constructor, we first set the Qt::WA_StaticContents
attribute on the widget. This attribute indicates that the widget
widget will receive paint events only for the newly visible part
of itself.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 1
+ \snippet widgets/tooltips/sortingbox.cpp 1
To be able to show the appropriate tooltips while the user is
moving the cursor around, we need to enable mouse tracking for the
enabled, the widget receives mouse move events even if no buttons
are pressed.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 2
+ \snippet widgets/tooltips/sortingbox.cpp 2
A widget's background role defines the brush from the widget's
palette that is used to render the background, and QPalette::Base
is typically white.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 3
+ \snippet widgets/tooltips/sortingbox.cpp 3
After creating the application's tool buttons using the private \c
createToolButton() function, we construct the shapes of a circle,
but they can be drawn many times using only calls to
QPainter::drawPath().
- \snippet widgets/widgets/tooltips/sortingbox.cpp 4
+ \snippet widgets/tooltips/sortingbox.cpp 4
Then we set the window title, resize the widget to a suitable
size, and finally create three initial shape items using the
private \c createShapeItem(), \c initialItemPosition() and \c
initialItemColor() functions.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 5
+ \snippet widgets/tooltips/sortingbox.cpp 5
QWidget::event() is the main event handler and receives all the
widget's events. Normally, we recommend reimplementing one of the
reason we reimplement the main event handler, and the first thing
we need to do is to determine the event's type:
- \snippet widgets/widgets/tooltips/sortingbox.cpp 6
+ \snippet widgets/tooltips/sortingbox.cpp 6
If the type is QEvent::ToolTip, we cast the event to a QHelpEvent,
otherwise we propagate the event using the QWidget::event()
QToolTip::showText() function needs the event's position in global
coordinates provided by QHelpEvent::globalPos().
- \snippet widgets/widgets/tooltips/sortingbox.cpp 7
+ \snippet widgets/tooltips/sortingbox.cpp 7
The \c resizeEvent() function is reimplemented to receive the
resize events dispatched to the widget. It makes sure that the
aligned in the application's bottom right corner, so each time the
main widget is resized we update the buttons geometry.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 8
+ \snippet widgets/tooltips/sortingbox.cpp 8
The \c paintEvent() function is reimplemented to receive paint
events for the widget. We create a QPainter for the \c SortingBox
widget, and run through the list of created shape items, drawing
each item at its defined position.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 9
+ \snippet widgets/tooltips/sortingbox.cpp 9
The painter will by default draw all the shape items at position
(0,0) in the \c SortingBox widget. The QPainter::translate()
drawn, otherwise the next shape item will appear at a position
relative to the item we drawed last.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 10
+ \snippet widgets/tooltips/sortingbox.cpp 10
The QPainter::setBrush() function sets the current brush used by
the painter. When the provided argument is a QColor, the function
QPainter::drawPath() function draws the given path using the
current pen for outline and the current brush for filling.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 11
+ \snippet widgets/tooltips/sortingbox.cpp 11
The \c mousePressEvent() function is reimplemented to receive the
mouse press events dispatched to the widget. It determines if an
repaint; instead it schedules a paint event for processing when Qt
returns to the main event loop.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 12
+ \snippet widgets/tooltips/sortingbox.cpp 12
The \c mouseMoveEvent() function is reimplemented to receive mouse
move events for the widget. If the left mouse button is pressed
corresponding to the offset between the positions of the current
mouse event and the previous one.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 13
+ \snippet widgets/tooltips/sortingbox.cpp 13
The \c mouseReleaseEvent() function is reimplemented to receive
the mouse release events dispatched to the widget. If the left
now. To move the item further, the user will need to press the
left mouse button again.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 14
+ \snippet widgets/tooltips/sortingbox.cpp 14
\codeline
- \snippet widgets/widgets/tooltips/sortingbox.cpp 15
+ \snippet widgets/tooltips/sortingbox.cpp 15
\codeline
- \snippet widgets/widgets/tooltips/sortingbox.cpp 16
+ \snippet widgets/tooltips/sortingbox.cpp 16
The \c createNewCircle(), \c createNewSquare() and \c
createNewTriangle() slots simply create new shape items, using the
private \c createShapeItem(), \c randomItemPosition() and \c
randomItemColor() functions.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 17
+ \snippet widgets/tooltips/sortingbox.cpp 17
In the \c itemAt() function, we run through the list of created
shape items to check if the given position is contained within the
-1. We run through the list backwards to get the index of the
uppermost shape item in case several items cover the position.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 18
+ \snippet widgets/tooltips/sortingbox.cpp 18
The \c moveItemTo() function moves the shape item in motion, and
the parameter \c pos is the position of a mouse event. First we
rectangle's top left corner, regardless of the item's previous
position.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 19
+ \snippet widgets/tooltips/sortingbox.cpp 19
Finally, we update the previous mouse event position, and make a
call to the QWidget::update() function to make the item appear at
its new position.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 20
+ \snippet widgets/tooltips/sortingbox.cpp 20
In the \c updateButtonGeometry() function we set the geometry for
the given button. The parameter coordinates define the bottom
QStyle::pixelMetric() to determine the widget's preferred default
spacing between its child widgets.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 21
+ \snippet widgets/tooltips/sortingbox.cpp 21
The \c createShapeItem() function creates a single shape item. It
sets the path, tooltip, position and color, using the item's own
make it appear with the other items within the \c SortingBox
widget.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 22
+ \snippet widgets/tooltips/sortingbox.cpp 22
The \c createToolButton() function is called from the \c
SortingBox constructor. We create a tool button with the given
and its size is 32 x 32 pixels. Before we return the button, we
connect it to the given slot.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 23
+ \snippet widgets/tooltips/sortingbox.cpp 23
The \c initialItemPosition() function is also called from the
constructor. We want the three first items to initially be
centered in the middle of the \c SortingBox widget, and we use
this function to calculate their positions.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 24
+ \snippet widgets/tooltips/sortingbox.cpp 24
Whenever the user creates a new shape item, we want the new item
to appear at a random position, and we use the \c
\c SortingBox widget, using the widget's current width and height
when calculating the random coordinates.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 25
+ \snippet widgets/tooltips/sortingbox.cpp 25
As with \c initialItemPosition(), the \c initialItemColor()
function is called from the constructor. The purposes of both
functions are purely cosmetic: We want to control the initial
position and color of the three first items.
- \snippet widgets/widgets/tooltips/sortingbox.cpp 26
+ \snippet widgets/tooltips/sortingbox.cpp 26
Finally the \c randomItemColor() function is implemented to give
the shape items the user creates, a random color.
\section1 ShapeItem Class Definition
- \snippet widgets/widgets/tooltips/shapeitem.h 0
+ \snippet widgets/tooltips/shapeitem.h 0
The \c ShapeItem class is a custom widget representing one single
shape item. The widget has a path, a position, a color and a
\section1 ShapeItem Class Implementation
- \snippet widgets/widgets/tooltips/shapeitem.cpp 0
+ \snippet widgets/tooltips/shapeitem.cpp 0
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 1
+ \snippet widgets/tooltips/shapeitem.cpp 1
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 2
+ \snippet widgets/tooltips/shapeitem.cpp 2
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 3
+ \snippet widgets/tooltips/shapeitem.cpp 3
This first group of functions simply return the objects that are
requested. The objects are returned as constants, i.e. they cannot
be modified.
- \snippet widgets/widgets/tooltips/shapeitem.cpp 4
+ \snippet widgets/tooltips/shapeitem.cpp 4
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 5
+ \snippet widgets/tooltips/shapeitem.cpp 5
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 6
+ \snippet widgets/tooltips/shapeitem.cpp 6
\codeline
- \snippet widgets/widgets/tooltips/shapeitem.cpp 7
+ \snippet widgets/tooltips/shapeitem.cpp 7
The last group of functions set or modify the shape item's path,
position, color and tooltip, respectively.
****************************************************************************/
/*!
- \example widgets/widgets/wiggly
+ \example widgets/wiggly
\title Wiggly Example
The Wiggly example shows how to animate a widget using
\section1 Dialog Class Definition
- \snippet widgets/widgets/wiggly/dialog.h 0
+ \snippet widgets/wiggly/dialog.h 0
The \c Dialog class provides a dialog widget that allows the user
to enter a text. The text is then rendered by \c WigglyWidget.
\section1 Dialog Class Implementation
- \snippet widgets/widgets/wiggly/dialog.cpp 0
+ \snippet widgets/wiggly/dialog.cpp 0
In the constructor we create a wiggly widget along with a
\l{QLineEdit}{line edit}, and we put the two widgets in a
\section1 WigglyWidget Class Definition
- \snippet widgets/widgets/wiggly/wigglywidget.h 0
+ \snippet widgets/wiggly/wigglywidget.h 0
The \c WigglyWidget class provides the wiggly line displaying the
text. We subclass QWidget and reimplement the standard \l
\section1 WigglyWidget Class Implementation
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 0
+ \snippet widgets/wiggly/wigglywidget.cpp 0
In the constructor, we make the widget's background slightly
lighter than the usual background using the QPalette::Midlight
timer events generated when the timer times out (every 60
milliseconds).
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 1
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 2
+ \snippet widgets/wiggly/wigglywidget.cpp 1
+ \snippet widgets/wiggly/wigglywidget.cpp 2
The \c paintEvent() function is called whenever a QPaintEvent is
sent to the widget. Paint events are sent to widgets that need to
font below the base line). If the descent equals the ascent, they
cancel out each other and the base line is at \c height() / 2.
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 3
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 4
+ \snippet widgets/wiggly/wigglywidget.cpp 3
+ \snippet widgets/wiggly/wigglywidget.cpp 4
Each time the \c paintEvent() function is called, we create a
QPainter object \c painter to draw the contents of the widget.
'V'). The result is that the text isn't perfectly centered. You
can verify this by typing "AVAVAVAVAVAV" in the line edit.
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 5
- \snippet widgets/widgets/wiggly/wigglywidget.cpp 6
+ \snippet widgets/wiggly/wigglywidget.cpp 5
+ \snippet widgets/wiggly/wigglywidget.cpp 6
The \c timerEvent() function receives all the timer events that
are generated for this widget. If a timer event is sent from the
****************************************************************************/
/*!
- \example widgets/widgets/windowflags
+ \example widgets/windowflags
\title Window Flags Example
The Window Flags example shows how to use the window flags
\section1 ControllerWindow Class Definition
- \snippet widgets/widgets/windowflags/controllerwindow.h 0
+ \snippet widgets/windowflags/controllerwindow.h 0
The \c ControllerWindow class inherits QWidget. The widget allows
the user to choose among the available window flags, and displays
\section1 ControllerWindow Class Implementation
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 0
+ \snippet widgets/windowflags/controllerwindow.cpp 0
In the constructor we first create the preview window. Then we
create the group boxes containing the available window flags using
QVBoxLayout, set the window title and refresh the preview window
using the \c updatePreview() slot.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 1
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 2
+ \snippet widgets/windowflags/controllerwindow.cpp 1
+ \snippet widgets/windowflags/controllerwindow.cpp 2
The \c updatePreview() slot is called whenever the user changes
any of the window flags. First we create an empty Qt::WindowFlags
\c flags, then we determine which one of the types that is checked
and add it to \c flags.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 3
+ \snippet widgets/windowflags/controllerwindow.cpp 3
We also determine which of the hints that are checked, and add
them to \c flags using an OR operator. We use \c flags to set the
window flags for the preview window.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 4
+ \snippet widgets/windowflags/controllerwindow.cpp 4
We adjust the position of the preview window. The reason we do
that, is that playing around with the window's frame may on some
\printuntil /^\}/
\endomit
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 5
+ \snippet widgets/windowflags/controllerwindow.cpp 5
The private \c createTypeGroupBox() function is called from the
constructor.
hints only affect top-level windows, we abandon the Qt::Widget
type.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 6
+ \snippet widgets/windowflags/controllerwindow.cpp 6
The private \c createHintsGroupBox() function is also called from
the constructor.
checkboxes into a QGridLayout and install the layout on the group
box.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 7
+ \snippet widgets/windowflags/controllerwindow.cpp 7
The private \c createCheckBox() function is called from \c
createHintsGroupBox().
the private \c updatePreview() slot, and return a pointer to the
checkbox.
- \snippet widgets/widgets/windowflags/controllerwindow.cpp 8
+ \snippet widgets/windowflags/controllerwindow.cpp 8
In the private \c createRadioButton() function it is a
QRadioButton we create with the provided text, and connect to the
\section1 PreviewWindow Class Definition
- \snippet widgets/widgets/windowflags/previewwindow.h 0
+ \snippet widgets/windowflags/previewwindow.h 0
The \c PreviewWindow class inherits QWidget. It is a custom widget
that displays the names of its currently set window flags in a
\section1 PreviewWindow Class Implementation
- \snippet widgets/widgets/windowflags/previewwindow.cpp 0
+ \snippet widgets/windowflags/previewwindow.cpp 0
In the constructor, we first create a QTextEdit and make sure that
it is read-only.
Then we create the \uicontrol Close button, and put both the widgets
into a QVBoxLayout before we set the window title.
- \snippet widgets/widgets/windowflags/previewwindow.cpp 1
+ \snippet widgets/windowflags/previewwindow.cpp 1
In our reimplementation of the \c setWindowFlags() function, we
first set the widgets flags using the QWidget::setWindowFlags()
Example for a one second (1000 millisecond) timer (from the
\l{widgets/analogclock}{Analog Clock} example):
- \snippet widgets/widgets/analogclock/analogclock.cpp 4
- \snippet widgets/widgets/analogclock/analogclock.cpp 5
- \snippet widgets/widgets/analogclock/analogclock.cpp 6
+ \snippet widgets/analogclock/analogclock.cpp 4
+ \snippet widgets/analogclock/analogclock.cpp 5
+ \snippet widgets/analogclock/analogclock.cpp 6
From then on, the \c update() slot is called every second.
projects / profile / ivi / qtbase.git / commitdiff