Tk_ImageChanged(3) Tk (4.0) 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
An image manager calls Tk_ImageChanged for an image whenever
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Tk_ImageChanged(3) Tk (4.0) Tk_ImageChanged(3)
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
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