Tk_ImageChanged
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
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)
