Bug 692353 - TIFFSEP always antialiases against full "black"
Summary: TIFFSEP always antialiases against full "black"
Status: RESOLVED WORKSFORME
Alias: None
Product: Ghostscript
Classification: Unclassified
Component: PDF Interpreter (show other bugs)
Version: master
Hardware: Macintosh MacOS X
: P4 normal
Assignee: Alex Cherepanov
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-07-18 13:22 UTC by Adam Augusta
Modified: 2013-06-11 09:53 UTC (History)
1 user (show)

See Also:
Customer:
Word Size: ---

Attachments
Simple 2-spot PDF (52.72 KB, application/pdf)
2011-07-18 13:22 UTC, Adam Augusta 		Details
50% field spot output (890 bytes, image/tiff)
2011-07-18 13:23 UTC, Adam Augusta 		Details
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Adam Augusta 2011-07-18 13:22:35 UTC 
Created attachment 7684 [details]
Simple 2-spot PDF

If I'm interpreting these results correctly, TIFFSEP always seems to antialias against solid "black", even if the adjacent spot isn't solid.

In this example, Spot #1 is a field of 50%.  Spot #2 is a flower on top of it.

When rasterized (result.s0.tif), the field of black is at 50%, except the pixels coincident with the flower, where some of the pixels are actually darker than 50%.

This bug may be associated with Bug 687674 and possibly Bug 692303.

gs -sDEVICE=tiffsep -dBATCH -dSAFER -dNOPAUSE -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -r72 -sOutputFile="result.tif" AntiAliasTest.pdf 

This was tested against the master (configured with --with-libiconv=no).
Comment 1 Adam Augusta 2011-07-18 13:23:16 UTC 
Created attachment 7685 [details]
50% field spot output
Comment 2 Ken Sharp 2013-06-11 09:53:53 UTC 
This appears to be fixed in current code, possibly as a result of fixing some of the other problems referenced above.