Bug 692303 - Artifacts in simple artwork when using a TIFF device
Summary: Artifacts in simple artwork when using a TIFF device
Status: RESOLVED FIXED
Alias: None
Product: Ghostscript
Classification: Unclassified
Component: Vectors (show other bugs)
Version: master
Hardware: PC Windows 7
: P4 normal
Assignee: Robin Watts
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-06-26 14:07 UTC by Adam Augusta
Modified: 2011-06-30 11:44 UTC (History)
2 users (show)

See Also:
Customer:
Word Size: ---


Attachments
A simple PDF with a vector-described flower with a spot color. (577.46 KB, application/pdf)
2011-06-26 14:07 UTC, Adam Augusta
Details
TIFFSEP output (764 bytes, image/tiff)
2011-06-26 14:09 UTC, Adam Augusta
Details
TIFF32NC output (7.03 KB, image/tiff)
2011-06-26 14:09 UTC, Adam Augusta
Details
PNGAlpha Output (1.04 KB, image/png)
2011-06-26 14:10 UTC, Adam Augusta
Details
flower3.pdf (3.28 KB, application/pdf)
2011-06-28 14:41 UTC, Robin Watts
Details

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Description Adam Augusta 2011-06-26 14:07:14 UTC
Created attachment 7609 [details]
A simple PDF with a vector-described flower with a spot color.
Comment 1 Adam Augusta 2011-06-26 14:09:24 UTC
Created attachment 7610 [details]
TIFFSEP output
Comment 2 Adam Augusta 2011-06-26 14:09:45 UTC
Created attachment 7611 [details]
TIFF32NC output
Comment 3 Adam Augusta 2011-06-26 14:10:06 UTC
Created attachment 7612 [details]
PNGAlpha Output
Comment 4 Adam Augusta 2011-06-26 14:15:23 UTC
A simple vector flower (PDF attached) is getting rasterized with unusual artifacts when using TIFFSEP or TIFF32NC.  The output looks perfect when PNGALPHA is used.

gs -dBATCH -dSAFER -dNOPAUSE -sDEVICE=tiffsep -r72 -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -sOutputFile=simple NoPaper.ai

This behavior is being exhibited in trunk.
Comment 5 Ken Sharp 2011-06-26 18:15:33 UTC
(In reply to comment #4)
> A simple vector flower (PDF attached) is getting rasterized with unusual
> artifacts when using TIFFSEP or TIFF32NC.  The output looks perfect when
> PNGALPHA is used.
> 
> gs -dBATCH -dSAFER -dNOPAUSE -sDEVICE=tiffsep -r72 -dGraphicsAlphaBits=4
> -dTextAlphaBits=4 -sOutputFile=simple NoPaper.ai

The bug report is against Windows, yet this is a Linux command line. The supplied file is a PDF, but the command line uses an Adobe Illustrator file.

Removing the -dGrpahicsAlphaBits causes the problem to go away, but I do see the described problem on Windows when that switch is present. Hard to see wy, since its a simple fill. One for Robin perhaps ?
Comment 6 Robin Watts 2011-06-28 14:41:53 UTC
Created attachment 7615 [details]
flower3.pdf

Simplified version of the file; doesn't need to be a spot colour or anything clever. Same problem occurs with ICC profiles, spot colors and clever graphics states all removed.
Comment 7 Robin Watts 2011-06-28 19:14:12 UTC
Fixed in:

commit a1ee78a6de94b8b4292b9ce3b71b54ed3ae7502b
Author: Robin Watts <Robin.Watts@artifex.com>
Date:   Tue Jun 28 20:09:11 2011 +0100

    Fix for Bug 692303, antialiasing problems.

    In trying to fix Bug 692081, I'd inadvertantly broken antialiased
    operation on shapes with multiple 'alpha=0'/'alpha-non-zero'
    transitions.

    My understanding of Peters line accumulator macros was incomplete.
    This new version seems to fix both cases.
Comment 8 Adam Augusta 2011-06-30 11:44:36 UTC
Following up with Bug 692318.