'\"
'\" Copyright (c) 1994 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" SCCS: @(#) ImgChanged.3 1.6 96/03/26 18:14:18
'\" 
.so man.macros
.TH Tk_ImageChanged 3 4.0 Tk "Tk Library Procedures"
.BS
.SH NAME
Tk_ImageChanged \- notify widgets that image needs to be redrawn
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
\fBTk_ImageChanged\fR(\fIimageMaster, x, y, width, height, imageWidth, imageHeight\fR)
.SH ARGUMENTS
.AS Tk_ImageMaster imageHeight
.AP Tk_ImageMaster imageMaster in
Token for image, which was passed to image's \fIcreateProc\fR when
the image was created.
.AP int x in
X-coordinate of upper-left corner of region that needs redisplay (measured
from upper-left corner of image).
.AP int y in
Y-coordinate of upper-left corner of region that needs redisplay (measured
from upper-left corner of image).
.AP "int" width in
Width of region that needs to be redrawn, in pixels.
.AP "int" height in
Height of region that needs to be redrawn, in pixels.
.AP "int" imageWidth in
Current width of image, in pixels.
.AP "int" imageHeight in
Current height of image, in pixels.
.BE

.SH DESCRIPTION
.PP
An image manager calls \fBTk_ImageChanged\fR for an image
whenever anything happens that requires the image to be redrawn.
As a result of calling \fBTk_ImageChanged\fR, any widgets using
the image are notified so that they can redisplay themselves
appropriately.
The \fIimageMaster\fR argument identifies the image, and
\fIx\fR, \fIy\fR, \fIwidth\fR, and \fIheight\fR
specify a rectangular region within the image that needs to
be redrawn.
\fIimageWidth\fR and \fIimageHeight\fR specify the image's (new) size.
.PP
An image manager should call \fBTk_ImageChanged\fR during
its \fIcreateProc\fR 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,
\fBTk_ImageChanged\fR should be called again with \fIx\fR, \fIy\fR,
\fIwidth\fR, and \fIheight\fR values that cover all the pixels
that changed.
If the size of the image should change, then \fBTk_ImageChanged\fR
must be called to indicate the new size, even if no pixels
need to be redisplayed.

.SH "SEE ALSO"
Tk_CreateImageType

.SH KEYWORDS
images, redisplay, image size changes
