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.
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