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 * An example of using the trackbar functionality can be found at opencv_source_code/samples/cpp/connected_components.cpp
42 Returns the trackbar position.
44 .. ocv:function:: int getTrackbarPos( const string& trackbarname, const string& winname )
46 .. ocv:pyfunction:: cv2.getTrackbarPos(trackbarname, winname) -> retval
48 .. ocv:cfunction:: int cvGetTrackbarPos( const char* trackbar_name, const char* window_name )
50 .. ocv:pyoldfunction:: cv.GetTrackbarPos(trackbarName, windowName) -> retval
52 :param trackbarname: Name of the trackbar.
54 :param winname: Name of the window that is the parent of the trackbar.
56 The function returns the current position of the specified trackbar.
60 **[Qt Backend Only]** ``winname`` can be empty (or NULL) if the trackbar is attached to the control panel.
64 Displays an image in the specified window.
66 .. ocv:function:: void imshow( const string& winname, InputArray mat )
68 .. ocv:pyfunction:: cv2.imshow(winname, mat) -> None
70 .. ocv:cfunction:: void cvShowImage( const char* name, const CvArr* image )
72 .. ocv:pyoldfunction:: cv.ShowImage(name, image) -> None
74 :param winname: Name of the window.
76 :param image: Image to be shown.
78 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:
80 * If the image is 8-bit unsigned, it is displayed as is.
82 * 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].
84 * 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].
86 If window was created with OpenGL support, ``imshow`` also support :ocv:class:`ogl::Buffer` , :ocv:class:`ogl::Texture2D` and :ocv:class:`gpu::GpuMat` as input.
92 .. ocv:function:: void namedWindow( const string& winname, int flags=WINDOW_AUTOSIZE )
94 .. ocv:pyfunction:: cv2.namedWindow(winname[, flags]) -> None
96 .. ocv:cfunction:: int cvNamedWindow( const char* name, int flags=CV_WINDOW_AUTOSIZE )
98 .. ocv:pyoldfunction:: cv.NamedWindow(name, flags=CV_WINDOW_AUTOSIZE)-> None
100 :param name: Name of the window in the window caption that may be used as a window identifier.
102 :param flags: Flags of the window. The supported flags are:
104 * **WINDOW_NORMAL** If this is set, the user can resize the window (no constraint).
106 * **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.
108 * **WINDOW_OPENGL** If this is set, the window will be created with OpenGL support.
110 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.
112 If a window with the same name already exists, the function does nothing.
114 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.
118 Qt backend supports additional flags:
120 * **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.
122 * **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.
124 * **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.
126 By default, ``flags == CV_WINDOW_AUTOSIZE | CV_WINDOW_KEEPRATIO | CV_GUI_EXPANDED``
133 .. ocv:function:: void destroyWindow( const string& winname )
135 .. ocv:pyfunction:: cv2.destroyWindow(winname) -> None
137 .. ocv:cfunction:: void cvDestroyWindow( const char* name )
139 .. ocv:pyoldfunction:: cv.DestroyWindow(name)-> None
141 :param winname: Name of the window to be destroyed.
143 The function ``destroyWindow`` destroys the window with the given name.
148 Destroys all of the HighGUI windows.
150 .. ocv:function:: void destroyAllWindows()
152 .. ocv:pyfunction:: cv2.destroyAllWindows() -> None
154 .. ocv:cfunction:: void cvDestroyAllWindows()
156 .. ocv:pyoldfunction:: cv.DestroyAllWindows()-> None
158 The function ``destroyAllWindows`` destroys all of the opened HighGUI windows.
163 Moves window to the specified position
165 .. ocv:function:: void moveWindow( const string& winname, int x, int y )
167 .. ocv:pyfunction:: cv2.moveWindow(winname, x, y) -> None
169 .. ocv:cfunction:: void cvMoveWindow( const char* name, int x, int y )
171 .. ocv:pyoldfunction:: cv.MoveWindow(name, x, y)-> None
173 :param winname: Window name
175 :param x: The new x-coordinate of the window
177 :param y: The new y-coordinate of the window
182 Resizes window to the specified size
184 .. ocv:function:: void resizeWindow( const string& winname, int width, int height )
186 .. ocv:pyfunction:: cv2.resizeWindow(winname, width, height) -> None
188 .. ocv:cfunction:: void cvResizeWindow( const char* name, int width, int height )
190 .. ocv:pyoldfunction:: cv.ResizeWindow(name, width, height)-> None
192 :param winname: Window name
194 :param width: The new window width
196 :param height: The new window height
200 * The specified window size is for the image area. Toolbars are not counted.
202 * Only windows created without CV_WINDOW_AUTOSIZE flag can be resized.
207 Sets mouse handler for the specified window
209 .. ocv:function:: void setMouseCallback( const string& winname, MouseCallback onMouse, void* userdata=0 )
211 .. ocv:cfunction:: void cvSetMouseCallback( const char* window_name, CvMouseCallback on_mouse, void* param=NULL )
213 .. ocv:pyoldfunction:: cv.SetMouseCallback(windowName, onMouse, param=None) -> None
215 :param winname: Window name
217 :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.
219 :param userdata: The optional parameter passed to the callback.
224 Sets the trackbar position.
226 .. ocv:function:: void setTrackbarPos( const string& trackbarname, const string& winname, int pos )
228 .. ocv:pyfunction:: cv2.setTrackbarPos(trackbarname, winname, pos) -> None
230 .. ocv:cfunction:: void cvSetTrackbarPos( const char* trackbar_name, const char* window_name, int pos )
232 .. ocv:pyoldfunction:: cv.SetTrackbarPos(trackbarName, windowName, pos)-> None
234 :param trackbarname: Name of the trackbar.
236 :param winname: Name of the window that is the parent of trackbar.
238 :param pos: New position.
240 The function sets the position of the specified trackbar in the specified window.
244 **[Qt Backend Only]** ``winname`` can be empty (or NULL) if the trackbar is attached to the control panel.
248 Waits for a pressed key.
250 .. ocv:function:: int waitKey(int delay=0)
252 .. ocv:pyfunction:: cv2.waitKey([delay]) -> retval
254 .. ocv:cfunction:: int cvWaitKey( int delay=0 )
256 .. ocv:pyoldfunction:: cv.WaitKey(delay=0)-> int
258 :param delay: Delay in milliseconds. 0 is the special value that means "forever".
260 The function ``waitKey`` waits for a key event infinitely (when
261 :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.
265 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.
269 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.
271 setOpenGlDrawCallback
272 ---------------------
273 Set OpenGL render handler for the specified window.
275 .. ocv:function:: void setOpenGlDrawCallback(const string& winname, OpenGlDrawCallback onOpenGlDraw, void* userdata = 0)
277 :param winname: Window name
279 :param onOpenGlDraw: Draw callback.
281 :param userdata: The optional parameter passed to the callback.
285 Sets the specified window as current OpenGL context.
287 .. ocv:function:: void setOpenGlContext(const string& winname)
289 :param winname: Window name
293 Force window to redraw its context and call draw callback ( :ocv:func:`setOpenGlDrawCallback` ).
295 .. ocv:function:: void updateWindow(const string& winname)
297 :param winname: Window name