Bug 691247 - jbig2dec doesn't handle halftone regions
Summary: jbig2dec doesn't handle halftone regions
Status: RESOLVED FIXED
Alias: None
Product: jbig2dec
Classification: Unclassified
Component: Missing Feature (show other bugs)
Version: master
Hardware: PC Linux
: P4 normal
Assignee: Henry Stiles
URL:
Keywords:
Depends on:
Blocks: 691230
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Reported: 2010-04-16 06:08 UTC by Ralph Giles
Modified: 2012-02-08 16:47 UTC (History)
3 users (show)

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Description Ralph Giles 2010-04-16 06:08:59 UTC 
The jbig2dec library doesn't have a decoder for halftone regions, and the two ubc testsuite files, amb_1.jb2 and abm_2.jb2 are not decoded correctly.

In both cases jbig2dec fails silently returning a blank (white) page. This is worse than failing with an error.

There is some code in jbig2_halftone.[ch] but it is incomplete. Gorac also contributed an implementation; see bug 690979 for Hin-Tak's factoring of that patch.

The library should be updated to handle halftone regions. For a long time this feature seemed to be unused in practice, but bug 691230 contains a wild file with a pattern region and corresponding dictionary.
Comment 1 Shailesh Mistry 2012-02-05 14:37:46 UTC 
This bug has now been resolved by the fix in Bug691230 and can be closed down.