Tk_ImageChanged(3tk)

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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

       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 iden-
       tifies  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                                    4.0                   Tk_ImageChanged(3)