8 Creates a trackbar and attaches it to the specified window.
10 .. ocv:function:: int createTrackbar( const string& trackbarname, const string& winname, int* value, int count, TrackbarCallback onChange=0, void* userdata=0)
12 .. ocv:cfunction:: int cvCreateTrackbar( const char* trackbar_name, const char* window_name, int* value, int count, CvTrackbarCallback on_change=NULL )
14 .. ocv:pyoldfunction:: cv.CreateTrackbar(trackbarName, windowName, value, count, onChange) -> None
16 :param trackbarname: Name of the created trackbar.
18 :param winname: Name of the window that will be used as a parent of the created trackbar.
20 :param value: Optional pointer to an integer variable whose value reflects the position of the slider. Upon creation, the slider position is defined by this variable.
22 :param count: Maximal position of the slider. The minimal position is always 0.
24 :param onChange: Pointer to the function to be called every time the slider changes position. This function should be prototyped as ``void Foo(int,void*);`` , where the first parameter is the trackbar position and the second parameter is the user data (see the next parameter). If the callback is the NULL pointer, no callbacks are called, but only ``value`` is updated.
26 :param userdata: User data that is passed as is to the callback. It can be used to handle trackbar events without using global variables.
28 The function ``createTrackbar`` creates a trackbar (a slider or range control) with the specified name and range, assigns a variable ``value`` to be a position synchronized with the trackbar and specifies the callback function ``onChange`` to be called on the trackbar position change. The created trackbar is displayed in the specified window ``winname``.
32 **[Qt Backend Only]** ``winname`` can be empty (or NULL) if the trackbar should be attached to the control panel.
34 Clicking the label of each trackbar enables editing the trackbar values manually.
38 Returns the trackbar position.
40 .. ocv:function:: int getTrackbarPos( const string& trackbarname, const string& winname )
42 .. ocv:pyfunction:: cv2.getTrackbarPos(trackbarname, winname) -> retval
44 .. ocv:cfunction:: int cvGetTrackbarPos( const char* trackbar_name, const char* window_name )
46 .. ocv:pyoldfunction:: cv.GetTrackbarPos(trackbarName, windowName) -> retval
48 :param trackbarname: Name of the trackbar.
50 :param winname: Name of the window that is the parent of the trackbar.
52 The function returns the current position of the specified trackbar.
56 **[Qt Backend Only]** ``winname`` can be empty (or NULL) if the trackbar is attached to the control panel.
60 Displays an image in the specified window.
62 .. ocv:function:: void imshow( const string& winname, InputArray mat )
64 .. ocv:pyfunction:: cv2.imshow(winname, mat) -> None
66 .. ocv:cfunction:: void cvShowImage( const char* name, const CvArr* image )
68 .. ocv:pyoldfunction:: cv.ShowImage(name, image) -> None
70 :param winname: Name of the window.
72 :param image: Image to be shown.
74 The function ``imshow`` displays an image in the specified window. If the window was created with the ``CV_WINDOW_AUTOSIZE`` flag, the image is shown with its original size. Otherwise, the image is scaled to fit the window. The function may scale the image, depending on its depth:
76 * If the image is 8-bit unsigned, it is displayed as is.
78 * If the image is 16-bit unsigned or 32-bit integer, the pixels are divided by 256. That is, the value range [0,255*256] is mapped to [0,255].
80 * If the image is 32-bit floating-point, the pixel values are multiplied by 255. That is, the value range [0,1] is mapped to [0,255].
87 .. ocv:function:: void namedWindow( const string& winname, int flags=WINDOW_AUTOSIZE )
89 .. ocv:pyfunction:: cv2.namedWindow(winname[, flags]) -> None
91 .. ocv:cfunction:: int cvNamedWindow( const char* name, int flags=CV_WINDOW_AUTOSIZE )
93 .. ocv:pyoldfunction:: cv.NamedWindow(name, flags=CV_WINDOW_AUTOSIZE)-> None
95 :param name: Name of the window in the window caption that may be used as a window identifier.
97 :param flags: Flags of the window. Currently the only supported flag is ``CV_WINDOW_AUTOSIZE`` . If this is set, the window size is automatically adjusted to fit the displayed image (see :ocv:func:`imshow` ), and you cannot change the window size manually.
99 The function ``namedWindow`` creates a window that can be used as a placeholder for images and trackbars. Created windows are referred to by their names.
101 If a window with the same name already exists, the function does nothing.
103 You can call :ocv:func:`destroyWindow` or :ocv:func:`destroyAllWindows` to close the window and de-allocate any associated memory usage. For a simple program, you do not really have to call these functions because all the resources and windows of the application are closed automatically by the operating system upon exit.
107 Qt backend supports additional flags:
109 * **CV_WINDOW_NORMAL or CV_WINDOW_AUTOSIZE:** ``CV_WINDOW_NORMAL`` enables you to resize the window, whereas ``CV_WINDOW_AUTOSIZE`` adjusts automatically the window size to fit the displayed image (see :ocv:func:`imshow` ), and you cannot change the window size manually.
111 * **CV_WINDOW_FREERATIO or CV_WINDOW_KEEPRATIO:** ``CV_WINDOW_FREERATIO`` adjusts the image with no respect to its ratio, whereas ``CV_WINDOW_KEEPRATIO`` keeps the image ratio.
113 * **CV_GUI_NORMAL or CV_GUI_EXPANDED:** ``CV_GUI_NORMAL`` is the old way to draw the window without statusbar and toolbar, whereas ``CV_GUI_EXPANDED`` is a new enhanced GUI.
115 By default, ``flags == CV_WINDOW_AUTOSIZE | CV_WINDOW_KEEPRATIO | CV_GUI_EXPANDED``
122 .. ocv:function:: void destroyWindow( const string& winname )
124 .. ocv:pyfunction:: cv2.destroyWindow(winname) -> None
126 .. ocv:cfunction:: void cvDestroyWindow( const char* name )
128 .. ocv:pyoldfunction:: cv.DestroyWindow(name)-> None
130 :param winname: Name of the window to be destroyed.
132 The function ``destroyWindow`` destroys the window with the given name.
137 Destroys all of the HighGUI windows.
139 .. ocv:function:: void destroyAllWindows()
141 .. ocv:pyfunction:: cv2.destroyAllWindows() -> None
143 .. ocv:cfunction:: void cvDestroyAllWindows()
145 .. ocv:pyoldfunction:: cv.DestroyAllWindows()-> None
147 The function ``destroyAllWindows`` destroys all of the opened HighGUI windows.
152 Moves window to the specified position
154 .. ocv:function:: void moveWindow( const string& winname, int x, int y )
156 .. ocv:pyfunction:: cv2.moveWindow(winname, x, y) -> None
158 .. ocv:cfunction:: void cvMoveWindow( const char* name, int x, int y )
160 .. ocv:pyoldfunction:: cv.MoveWindow(name, x, y)-> None
162 :param winname: Window name
164 :param x: The new x-coordinate of the window
166 :param y: The new y-coordinate of the window
171 Resizes window to the specified size
173 .. ocv:function:: void resizeWindow( const string& winname, int width, int height )
175 .. ocv:pyfunction:: cv2.resizeWindow(winname, width, height) -> None
177 .. ocv:cfunction:: void cvResizeWindow( const char* name, int width, int height )
179 .. ocv:pyoldfunction:: cv.ResizeWindow(name, width, height)-> None
181 :param winname: Window name
183 :param width: The new window width
185 :param height: The new window height
189 * The specified window size is for the image area. Toolbars are not counted.
191 * Only windows created without CV_WINDOW_AUTOSIZE flag can be resized.
196 Sets mouse handler for the specified window
198 .. ocv:function:: void setMouseCallback( const string& winname, MouseCallback onMouse, void* userdata=0 )
200 .. ocv:cfunction:: void cvSetMouseCallback( const char* window_name, CvMouseCallback on_mouse, void* param=NULL )
202 .. ocv:pyoldfunction:: cv.SetMouseCallback(windowName, onMouse, param=None) -> None
204 :param winname: Window name
206 :param onMouse: Mouse callback. See OpenCV samples, such as http://code.opencv.org/projects/opencv/repository/revisions/master/entry/samples/cpp/ffilldemo.cpp, on how to specify and use the callback.
208 :param userdata: The optional parameter passed to the callback.
213 Sets the trackbar position.
215 .. ocv:function:: void setTrackbarPos( const string& trackbarname, const string& winname, int pos )
217 .. ocv:pyfunction:: cv2.setTrackbarPos(trackbarname, winname, pos) -> None
219 .. ocv:cfunction:: void cvSetTrackbarPos( const char* trackbar_name, const char* window_name, int pos )
221 .. ocv:pyoldfunction:: cv.SetTrackbarPos(trackbarName, windowName, pos)-> None
223 :param trackbarname: Name of the trackbar.
225 :param winname: Name of the window that is the parent of trackbar.
227 :param pos: New position.
229 The function sets the position of the specified trackbar in the specified window.
233 **[Qt Backend Only]** ``winname`` can be empty (or NULL) if the trackbar is attached to the control panel.
237 Waits for a pressed key.
239 .. ocv:function:: int waitKey(int delay=0)
241 .. ocv:pyfunction:: cv2.waitKey([delay]) -> retval
243 .. ocv:cfunction:: int cvWaitKey( int delay=0 )
245 .. ocv:pyoldfunction:: cv.WaitKey(delay=0)-> int
247 :param delay: Delay in milliseconds. 0 is the special value that means "forever".
249 The function ``waitKey`` waits for a key event infinitely (when
250 :math:`\texttt{delay}\leq 0` ) or for ``delay`` milliseconds, when it is positive. Since the OS has a minimum time between switching threads, the function will not wait exactly ``delay`` ms, it will wait at least ``delay`` ms, depending on what else is running on your computer at that time. It returns the code of the pressed key or -1 if no key was pressed before the specified time had elapsed.
254 This function is the only method in HighGUI that can fetch and handle events, so it needs to be called periodically for normal event processing unless HighGUI is used within an environment that takes care of event processing.
258 The function only works if there is at least one HighGUI window created and the window is active. If there are several HighGUI windows, any of them can be active.