Tk_ImageChanged(3tk)

Tk_ImageChanged(3)    Tk Library Procedures    Tk_ImageChanged(3)

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NAME

     Tk_ImageChanged - notify widgets  that  image  needs  to  be
     redrawn

SYNOPSIS

     #include <tk.h>

     Tk_ImageChanged(imageMaster, x, y, width, height, imageWidth, imageHeight)

ARGUMENTS

     Tk_ImageMaster imageMaster (in)          Token  for   image,
                                              which was passed to
                                              image's  createProc
                                              when  the image was
                                              created.

     int x (in)                               X-coordinate     of
                                              upper-left   corner
                                              of   region    that
                                              needs     redisplay
                                              (measured      from
                                              upper-left   corner
                                              of image).

     int y (in)                               Y-coordinate     of
                                              upper-left   corner
                                              of   region    that
                                              needs     redisplay
                                              (measured      from
                                              upper-left   corner
                                              of image).

     int width (in)                           Width   of   region
                                              that  needs  to  be
                                              redrawn, in pixels.

     int height (in)                          Height  of   region
                                              that  needs  to  be
                                              redrawn, in pixels.

     int imageWidth (in)                      Current  width   of
                                              image, in pixels.

     int imageHeight (in)                     Current  height  of
                                              image, in pixels.
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DESCRIPTION

Tk                      Last change: 4.0                        1

Tk_ImageChanged(3)    Tk Library Procedures    Tk_ImageChanged(3)

     An image manager calls Tk_ImageChanged for an image whenever
     anything  happens that requires the image to be redrawn.  As
     a result of calling Tk_ImageChanged, any widgets  using  the
     image  are  notified  so  that they can redisplay themselves
     appropriately.   The  imageMaster  argument  identifies  the
     image,  and  x,  y,  width, and height specify a rectangular
     region  within  the  image  that  needs   to   be   redrawn.
     imageWidth and imageHeight specify the image's (new) size.

     An image manager  should  call  Tk_ImageChanged  during  its
     createProc  to specify the image's initial size and to force
     redisplay if there are existing instances for the image.  If
     any of the pixel values in the image should change later on,
     Tk_ImageChanged should be called again with x, y, width, and
     height  values  that  cover all the pixels that changed.  If
     the size of the image should  change,  then  Tk_ImageChanged
     must  be  called to indicate the new size, even if no pixels
     need to be redisplayed.

SEE ALSO

     Tk_CreateImageType

KEYWORDS

     images, redisplay, image size changes

Tk                      Last change: 4.0                        2