[gs-bugs] [Bug 698672] - Ghostscript - Odd rendering with new scan converter and GraphicsAlphaBits

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Bug ID: 698672
Summary: Odd rendering with new scan converter and
GraphicsAlphaBits
Product: Ghostscript
Version: master
Hardware: PC
OS: Windows 7
Status: UNCONFIRMED
Severity: normal
Priority: P4
Component: Graphics Library
Assignee: ghostpdl-***@artifex.com
Reporter: ***@artifex.com
QA Contact: gs-***@ghostscript.com
Word Size: ---

Created attachment 14397
--> http://bugs.ghostscript.com/attachment.cgi?id=14397&action=edit
much reduced sampl efile

The customer reports that the file when rendered with:

gswin32c.exe -q -dNOPAUSE -sDEVICE=tiff24nc -r600x600 -dGraphicsAlphaBits=4
-sOutputFile=5.tif GraphicsAlpha.pdf

produces odd gray sections in the body of the black line. This is visible
throughout the line section though the customer bitmap focuses on teh 'U'
shaped section near the centre of the line.

Using the old scan covnerter (-dSCANCONVERTERTYPE=0) ro not using
GraphicsAlphaBits renders a solid line.

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Ken Sharp <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Customer| |2
Priority|P4 |P2
Assignee|ghostpdl-***@artifex.com |***@artifex.com

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Ray Johnston <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Customer|2 |531
Priority|P2 |P1

--- Comment #1 from Ray Johnston <***@artifex.com> ---
Correct the customer number and priority

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Robin Watts <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Customer|531 |2
Priority|P1 |P2
Resolution|--- |FIXED

--- Comment #2 from Robin Watts <***@artifex.com> ---
Fixed in commit:

commit 684f73e8deefacb2aa5d2277f3154b68809b2ab7 (HEAD -> master,
golden/master)Author: Robin Watts <***@artifex.com>
Date: Thu Oct 19 13:01:46 2017 +0100

Bug 698672: Fix new scanconverter/alphabits interaction.

The alphabits mechanism relies on the scan converter not
writing trapezoids so tall as to cause its line buffers
to flush too early.

This is achieved by honoring the max_band_height field in
the device header. Previously the new scan converter was
ignoring this. Here we alter the code to pay attention to
it.

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Robin Watts <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P1
Customer|2 |531

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Ken Sharp <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |NOTIFIED

[b***@artifex.com]

http://bugs.ghostscript.com/show_bug.cgi?id=698672

Chris Liddell (chrisl) <***@artifex.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@mavericklabel.com

--- Comment #3 from Chris Liddell (chrisl) <***@artifex.com> ---
*** Bug 698713 has been marked as a duplicate of this bug. ***