Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-lcc!lll-winken!uunet!mcvax!inria!lri!chatty
From: chatty@lri.lri.fr (Stephane Chatty)
Newsgroups: comp.windows.x
Subject: Pixmaps modified when used as stipples.
Message-ID: <374@lri.lri.fr>
Date: 1 Apr 89 13:08:03 GMT
Sender: chatty@lri.lri.fr
Lines: 89


Our X server modifies the pixmaps used as stipples in a GC when they do not have
the 'best size'.

We work on a SUN3/60, and our server is MIT's X11r3 with fixes 1-8, Purdue and
Purdue+ patches, and was compiled with gcc-1.33.
The 'best size' for stipples is 32x32, and when we use a 16x16 bitmap for 
filling a rectangle on another pixmap, in FillStippled mode, our bitmap is 
changed into a 32x16 one! Is it a feature of X that stipples are not kept, 
or is it a bug of our server ?

Here is a little program which shows that behaviour. As it is hard to get info 
from a Pixmap, we test them by making cursors in a sample window. We could as 
well have used a XCopyPlane.

---------------------------------------------------------------------------

#include <X11/Xlib.h>

#define arrow_width 16
#define arrow_height 16
static char arrow_bits[] = {
   0xff, 0xff, 0x1f, 0xf8, 0xdf, 0xfb, 0xdf, 0xfb, 0xdf, 0xfb, 0xdf, 0xfb,
   0xdf, 0xfb, 0xdf, 0xfb, 0xc3, 0xc3, 0xfb, 0xdf, 0xf7, 0xef, 0xef, 0xf7,
   0xdf, 0xfb, 0xbf, 0xfd, 0x7f, 0xfe, 0xff, 0xff};



main ()
{
	Display* dpy;
	int scn;
	GC gc;
	Pixmap source = 0;
	Pixmap result;

	Window test_window;
	Colormap cmap;
	XColor WHITE, BLACK, c;
	Cursor test_cursor;

	dpy = XOpenDisplay (0);
	scn = DefaultScreen (dpy);

	/* What we need for testing pixmaps : */
	cmap = DefaultColormap (dpy, scn);
	XAllocNamedColor (dpy, cmap, "white", &WHITE, &c);
	XAllocNamedColor (dpy, cmap, "black", &BLACK, &c);
	test_window = XCreateSimpleWindow (dpy, RootWindow (dpy, scn), 50, 1,
			50, 50, 2, BlackPixel (dpy, scn), WhitePixel (dpy, scn));
	XMapWindow (dpy, test_window);
	XFlush (dpy);	
	
	/* The graphic context */
	gc = XCreateGC (dpy, RootWindow (dpy, scn), 0, 0);
	XSetFillStyle (dpy, gc, FillStippled);
	
	/* Load a pixmap from data, and call it 'source' */
	source = XCreateBitmapFromData (dpy, RootWindow (dpy, scn),
				arrow_bits, arrow_width, arrow_height);

	/* Create another pixmap from scratch */
	result = XCreatePixmap (dpy, RootWindow (dpy, scn), 
			arrow_width, arrow_height, 1);

	/* Use 'source' as a stipple for drawing */
	XSetStipple (dpy, gc, source);
	
	/* A simple test for a pixmap : use it as a cursor  */
	test_cursor = XCreatePixmapCursor (dpy, source, 
			source, &BLACK, &WHITE, 0, 0);
	XDefineCursor (dpy, test_window, test_cursor);
	XFlush (dpy);
	getchar ();

	/*Draw in 'result', using 'source' as a stipple */
	XFillRectangle (dpy, result, gc, 0, 0, arrow_width, arrow_height);
	
	/* Check 'source' again : it has been modified !! */
	test_cursor = XCreatePixmapCursor (dpy, source, 
			source, &BLACK, &WHITE, 0, 0);
	XDefineCursor (dpy, test_window, test_cursor);
	XFlush (dpy);
	getchar ();
}

-------------------------------------------------------------------------------

   Stephane CHATTY	        chatty@frlri61.bitnet, chatty@lri.lri.fr