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From: alba...@wco.com (Al Petrofsky)
Subject: bug in display of interpolated images on X11 device
Date: 1997/03/28
Message-ID: <87g1xgz74o.fsf@albatros.wco.com>#1/1
X-Deja-AN: 229396559
Sender: a...@albatros.wco.com
X-Server-Date: 28 Mar 1997 09:40:58 GMT
Organization: The Vegetable Liberation Front
x-gateway: relay5.UU.NET from bug-ghostscript to gnu.ghostscript.bug; Sun, 30 Mar 1997 01:53:26 EST
Newsgroups: gnu.ghostscript.bug



Ghostscript version: 4.03

Where you got Ghostscript: ftp.cs.wisc.edu

Hardware you are using: i586 PC

Operating system you are using: Debian 1.2 Linux, kernel 2.0.27

(If you compiled Ghostscript yourself)
C compiler you are using (including compiler version): gcc 2.7.2.1

Environment variables (GS_DEVICE, GS_FONTPATH, GS_LIB, GS_OPTIONS): 

Command line: gs interpolated.ps

URL or FTP location of test file(s), if relevant: 
    http://www.wco.com/~albatros/interpolated.ps

(Use as much space as you need for the remaining items.)
Symptoms:

   Segmentation fault in XPutImage, called from x_copy_color in gdevx.c

   I am using XFree86 3.2 (X11R6.1) libraries and server on a 15-bit
   truecolor display.

Suggested fix (if any):

       I'm not sure what the fix is, but the following code (from
    x_copy_color in gdevx.c) creates a malformed image just before the
    call to XPutImage:

	  {    xdev->image.width = raster << 3;
	       xdev->image.height = h;
	       xdev->image.format = ZPixmap;
	       xdev->image.data = (char *)base;
	       xdev->image.depth = depth;
	       xdev->image.bytes_per_line = raster;
	       xdev->image.bits_per_pixel = depth;
	       XPutImage(xdev->dpy, xdev->dest, xdev->gc, &xdev->image,
			 sourcex, 0, x, y, w, h);
   
      This makes image.width eight times as big as image.bytes_per_line,
    which only makes sense if depth is 1.  The width should be at most
    (bytes_per_line * 8 / bits_per_pixel).

Other comments:

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