Bug 686782

Created attachment 42 [details]
PC_AI9_transparency_raster_AI.zip

The image is still different than Adobe Acrobat Reader shows, but
I am not sure if it correct. I don't have Illustrator 9 or 10 to
see what it shows.

The image3x handling would sometimes check mask.InterleaveType even 
though this was not initialized if mask depth was 0 (that mask was
not being used).

This could result in data garbling and hangs.

I'm not sure why the file sometimes ran 'slow', but I was able to
get consitent results using -Z@ which woudl define the mask
InterleaveType to an invalid value. The customer reported 20 minute
times. I see 2:20 on casper to the bitrgb device and 3:30 on my
system to a 24-bit RGB display at 96dpi (same resolution and bit
depth as I used on casper).

The time for Adobe Acrobat Reader to display the file was 65sec
on my system (a 2:1 performance difference isn't horrible like
a 20:1 performance difference would be).

Interestingly the time for a debug version on casper was 3:57
and 3:30 on my system. The gcc compiler may have superior
optimization.

I was able to reproduce infinite loops without the fix.

Rather than adding a check for mask[i].depth > 0 in a couple of
places, I just set the InterleaveType to 0. As long as it is not
interleave_separate_source or interleave_chunky, everything works
as far as I can test.

The patch for the UMR part of the problem is:

--- src/gximag3x.c      7 Oct 2002 08:28:56 -0000       1.13
+++ src/gximag3x.c      28 Mar 2003 18:06:29 -0000
@@ -385,6 +385,7 @@
 
     if (pimm->MaskDict.BitsPerComponent == 0) { /* mask missing */
        pmcs->depth = 0;
+       pmcs->InterleaveType = 0;       /* an invalid type */
        return 0;
     }
     if (mask_height <= 0)
 

With the following patch (to be committed soon, pending regression results from
recent commit), the file renders correctly:

http://www.ghostscript.com/pipermail/gs-code-review/2003-October/004190.html

Rendering is still slow, but it is also slow in Acrobat Reader 5. Thus, I am
closing the bug. We will be doing further speed optimizations on PDF 1.4 rendering.