diff options
Diffstat (limited to 'tk8.6/doc/GetImage.3')
-rw-r--r-- | tk8.6/doc/GetImage.3 | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/tk8.6/doc/GetImage.3 b/tk8.6/doc/GetImage.3 new file mode 100644 index 0000000..f2407bc --- /dev/null +++ b/tk8.6/doc/GetImage.3 @@ -0,0 +1,130 @@ +'\" +'\" 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. +'\" +.TH Tk_GetImage 3 4.0 Tk "Tk Library Procedures" +.so man.macros +.BS +.SH NAME +Tk_GetImage, Tk_RedrawImage, Tk_SizeOfImage, Tk_FreeImage \- use an image in a widget +.SH SYNOPSIS +.nf +\fB#include <tk.h>\fR +.sp +Tk_Image +\fBTk_GetImage\fR(\fIinterp, tkwin, name, changeProc, clientData\fR) +.sp +\fBTk_RedrawImage\fR(\fIimage, imageX, imageY, width, height, drawable, drawableX, drawableY\fR) +.sp +\fBTk_SizeOfImage\fR(\fIimage, widthPtr, heightPtr\fR) +.sp +\fBTk_FreeImage\fR(\fIimage\fR) +.SH ARGUMENTS +.AS Tk_ImageChangedProc *changeProc +.AP Tcl_Interp *interp in +Place to leave error message. +.AP Tk_Window tkwin in +Window in which image will be used. +.AP "const char" *name in +Name of image. +.AP Tk_ImageChangedProc *changeProc in +Procedure for Tk to invoke whenever image content or size changes. +.AP ClientData clientData in +One-word value for Tk to pass to \fIchangeProc\fR. +.AP Tk_Image image in +Token for image instance; must have been returned by a previous +call to \fBTk_GetImage\fR. +.AP int imageX in +X-coordinate of upper-left corner of region of image to redisplay +(measured in pixels from the image's upper-left corner). +.AP int imageY in +Y-coordinate of upper-left corner of region of image to redisplay +(measured in pixels from the image's upper-left corner). +.AP "int" width (in) +Width of region of image to redisplay. +.AP "int" height (in) +Height of region of image to redisplay. +.AP Drawable drawable in +Where to display image. Must either be window specified to +\fBTk_GetImage\fR or a pixmap compatible with that window. +.AP int drawableX in +Where to display image in \fIdrawable\fR: this is the x-coordinate +in \fIdrawable\fR where x-coordinate \fIimageX\fR of the image +should be displayed. +.AP int drawableY in +Where to display image in \fIdrawable\fR: this is the y-coordinate +in \fIdrawable\fR where y-coordinate \fIimageY\fR of the image +should be displayed. +.AP "int" widthPtr out +Store width of \fIimage\fR (in pixels) here. +.AP "int" heightPtr out +Store height of \fIimage\fR (in pixels) here. +.BE +.SH DESCRIPTION +.PP +These procedures are invoked by widgets that wish to display images. +\fBTk_GetImage\fR is invoked by a widget when it first decides to +display an image. +\fIname\fR gives the name of the desired image and \fItkwin\fR +identifies the window where the image will be displayed. +\fBTk_GetImage\fR looks up the image in the table of existing +images and returns a token for a new instance of the image. +If the image does not exist then \fBTk_GetImage\fR returns NULL +and leaves an error message in interpreter \fIinterp\fR's result. +.PP +When a widget wishes to actually display an image it must +call \fBTk_RedrawImage\fR, identifying the image (\fIimage\fR), +a region within the image to redisplay (\fIimageX\fR, \fIimageY\fR, +\fIwidth\fR, and \fIheight\fR), and a place to display the +image (\fIdrawable\fR, \fIdrawableX\fR, and \fIdrawableY\fR). +Tk will then invoke the appropriate image manager, which will +display the requested portion of the image before returning. +.PP +A widget can find out the dimensions of an image by calling +\fBTk_SizeOfImage\fR: the width and height will be stored +in the locations given by \fIwidthPtr\fR and \fIheightPtr\fR, +respectively. +.PP +When a widget is finished with an image (e.g., the widget is +being deleted or it is going to use a different image instead +of the current one), it must call \fBTk_FreeImage\fR to +release the image instance. +The widget should never again use the image token after passing +it to \fBTk_FreeImage\fR. +There must be exactly one call to \fBTk_FreeImage\fR for each +call to \fBTk_GetImage\fR. +.PP +If the contents or size of an image changes, then any widgets +using the image will need to find out about the changes so that +they can redisplay themselves. +The \fIchangeProc\fR and \fIclientData\fR arguments to +\fBTk_GetImage\fR are used for this purpose. +\fIchangeProc\fR will be called by Tk whenever a change occurs +in the image; it must match the following prototype: +.CS +typedef void \fBTk_ImageChangedProc\fR( + ClientData \fIclientData\fR, + int \fIx\fR, + int \fIy\fR, + int \fIwidth\fR, + int \fIheight\fR, + int \fIimageWidth\fR, + int \fIimageHeight\fR); +.CE +The \fIclientData\fR argument to \fIchangeProc\fR is the same as the +\fIclientData\fR argument to \fBTk_GetImage\fR. +It is usually a pointer to the widget record for the widget or +some other data structure managed by the widget. +The arguments \fIx\fR, \fIy\fR, \fIwidth\fR, and \fIheight\fR +identify a region within the image that must be redisplayed; +they are specified in pixels measured from the upper-left +corner of the image. +The arguments \fIimageWidth\fR and \fIimageHeight\fR give +the image's (new) size. +.SH "SEE ALSO" +Tk_CreateImageType +.SH KEYWORDS +images, redisplay |