Bug 693211

Summary: line disapeer with increased resolution
Product: Ghostscript Reporter: roucaries.bastien+gs
Component: Other DriverAssignee: Default assignee <ghostpdl-bugs>
Status: RESOLVED WORKSFORME    
Severity: normal CC: alex, chris.liddell
Priority: P4    
Version: 9.05   
Hardware: PC   
OS: Linux   
Customer: Word Size: ---
Attachments: Simplified sample file

Description roucaries.bastien+gs 2012-07-23 14:35:15 UTC
from http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=339467

At -r25 (frame-gs25.png),
the 4 borders are displayed. But at -r50 (frame-gs50.png), only 2
are displayed. The images were generated with:

gs < /dev/null -sDEVICE=png16m -sOutputFile=frame-gs25.png -r25 frame-rr.pdf
gs < /dev/null -sDEVICE=png16m -sOutputFile=frame-gs50.png -r50 frame-rr.pdf

Seems strange that improving resolution, decrease quality...

Bastien
Comment 1 Alex Cherepanov 2012-07-23 15:45:12 UTC
This file also shows similar resolution-dependant effects on Acrobat Reader.
Comment 2 Chris Liddell (chrisl) 2012-07-23 15:52:25 UTC
In addition to above, also shows resolution dependant effects on xpdf, poppler, Jaws and Harlequin.

To me, that points the finger at the producer rather than consumer (in this case "producer" does not mean GS 5.x which converted presumably PS into PDF, but the application which originally create the PS).
Comment 3 Alex Cherepanov 2012-07-23 20:47:00 UTC
Created attachment 8790 [details]
Simplified sample file
Comment 4 Alex Cherepanov 2012-07-24 03:01:56 UTC
This is an interaction between the bounding box of a form and a rectangle
that is partly stroked about 0.5 pt outside of the bounding box with 1 pt line.
The effect depends on relative rounding of the bounding box and the stroked path.
The line position is also a subject of stroke adjust.

Ghostscript cannot know that the user wanted to draw a frame.
It just rounds every object independently and draws the result.