Bug 689044 - Anti-aliasing does not work when reading a PDF
Summary: Anti-aliasing does not work when reading a PDF
Status: NOTIFIED FIXED
Alias: None
Product: Ghostscript
Classification: Unclassified
Component: Color (show other bugs)
Version: 8.71
Hardware: All All
: P2 normal
Assignee: Michael Vrhel
URL:
Keywords:
: 691821 (view as bug list)
Depends on:
Blocks:
 
Reported: 2007-01-15 15:57 UTC by Arthur
Modified: 2011-10-02 02:35 UTC (History)
4 users (show)

See Also:
Customer: 580
Word Size: ---


Attachments
The PDF that I am trying to convert (188.19 KB, application/pdf)
2007-01-15 16:00 UTC, Arthur
Details

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Description Arthur 2007-01-15 15:57:50 UTC
I am trying to use ghostscript to convert PDFs to TIFFs. It works nicely except
that anti-aliasing does not appear to happen even when I request it.

I am using:
gs -dSAFER  -dBATCH -dNOPAUSE -sDEVICE=tiff24nc  -dGraphicsAlphaBits=4
-dTextAlphaBits=4 -r600 -sOutputFile=00test.tiff Raze.pdf

I will attach Raze.pdf in case it is specific to that PDF. Converting the PDF to
PS (pdf2ps) and then using the above command on it works and correctly
anti-aliases the image, but the page size is messed up.
Comment 1 Arthur 2007-01-15 16:00:39 UTC
Created attachment 2681 [details]
The PDF that I am trying to convert

This is the PDF I had trouble with. It is an odd size (2.47in x 3.47in) and was
created by OpenOffice.org 2.
Comment 2 Arthur 2007-01-15 22:41:52 UTC
I have investigated more.

I was using ESP GS 8.15 (not GPL GS). And on it the anti-aliasing works as long
as no images with alpha are used on the OpenOffice document. I was using a PNG
with an alpha channel.

On GPL GS 8.54 the same PDFs cause problems, but they cause a segfault instead
of incorrect rendering.

Comment 3 Ray Johnston 2008-08-21 13:54:19 UTC
This is a known issue that a PDF with transparency turns off anti-alias.

This is probably a duplicate.
Comment 4 Ray Johnston 2010-04-13 20:23:41 UTC
Customer reports the same thing. I do get anti-alias effects on the black text using -dGraphicsAlphaBits=4 (text is filled areas, not real text), but only if I set -dNOTRANSPARENCY, and then the "logo" is seriously wrong.

Attaching customer file.
Comment 6 Ray Johnston 2010-12-07 21:08:16 UTC
*** Bug 691821 has been marked as a duplicate of this bug. ***
Comment 7 Manuel Morales 2011-01-21 23:31:39 UTC
I'm also suffering from this one. Text not antialiased if a transparent object is behind. Using -dNOTRANSPARENCY makes text antialiased, but not useful as it disables transparency. Happens the same on Linux and Windows. This is the command I'm using:

$ gs -q -dNOTRANSPARENCY -dDOINTERPOLATE -dNOPAUSE -dBATCH -r193 -dGraphicsAlphaBits=4 -sDEVICE=png16m -dTextAlphaBits=4 -dEPSCrop -dFirstPage=1 -dLastPage=1 -sOutputFile="slide-1.png" my_file.pdf

Any progress on this? How can I help? It's very important for us to fix it. Email me for anything you could need.
Comment 8 cgilling 2011-03-23 01:20:10 UTC
Hi Ray,

I saw that in bug 691821 (the one marked as a duplicate of this bug) you had output that looked like this:

Page 1 MediaBox: [ 612 792 ]
Page 2 MediaBox: [ 612 792 ]     Page uses transparency features

I tried looking around the ghostscript checkout for something that would produce this output. The closest I would find was pdf_info.ps, but this doesn't print out transparency info.

I was wondering if you could point me to what you used to produce this output (or perhaps modifications you make to the pdf_info.ps file if thats what you did), as I am trying to determine how big a problem this issue is for a project that I am working on.

Thanks
Comment 9 Michael Vrhel 2011-04-01 18:11:24 UTC
Fixed with rev 12341