Tk_ImageChanged(3) Tk Library Procedures Tk_ImageChanged(3)_________________________________________________________________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 cre-
ateProc when the
image was cre-
ated.
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 pix-
els.
int height (in) Height of region
that needs to be
redrawn, in pix-
els.
int imageWidth (in) Current width of
image, in pixels.
int imageHeight (in) Current height of
image, in pixels.
_________________________________________________________________Tk 4.0 1
Tk_ImageChanged(3) Tk Library Procedures Tk_ImageChanged(3)DESCRIPTION
An image manager calls Tk_ImageChanged for an image when-
ever anything happens that requires the image to be
redrawn. As a result of calling Tk_ImageChanged, any wid-
gets using the image are notified so that they can redis-
play 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 4.0 2