[poppler] Testing color management functionality

[Leonard Rosenthol]

The overprint tests are something that will only work on devices that support Overprint (or Overprint simulation, in the case of Adobe Acrobat/Reader) - this is beyond the normal "color management" work.

I would work on color management WITHOUT transparency first - it's much simpler. Once you have that working, then you can work on how CM integrates with the PDF transparency model (of which Poppler only does about 1%).

Leonard

-----Original Message-----
From: poppler-bounces at lists.freedesktop.org [mailto:poppler-bounces at lists.freedesktop.org] On Behalf Of Hal V. Engel
Sent: Wednesday, May 13, 2009 2:28 PM
To: poppler at lists.freedesktop.org
Subject: [poppler] Testing color management functionality

Now that it looks like the color management support will be released with 
version 0.12 I decided to do some more testing.  I did this testing using a 
patched version of the Qt4 demo viewer (the same patch set I sent to the email 
list on Monday) using the altona pdf test suite 
http://www.eci.org/doku.php?id=en:downloads.  This test suite has tests for 
many things but I was only interested in those that were related to color 
rendering.

The most significant issues are with the following test elements:

#26 "Duotone and Spot Color"  Poppler fails the spot color test but appears to 
work for the doutone test.

#27 "Overprinting spot color and process color black"  Only the overprinted 
color is displayed.

#28 "Overprinting process colors only"  Only the overprinted color is 
displayed.

#34 through #38 These are renderings involving different source color spaces 
and/or different rendering intents.  Currently the color management code in 
poppler does not handle rendering intents and this shows up in tests #35 
through #38.  But it also appears that CM is not functioning at all for vector 
elements (test #34). 

The altone test suite appears to be comprehensive and is a harsh test of any 
PDF rendering engine but it should help to find and correct rendering issues 
since each test element only tests a specific well documented feature.  

Not all of the above issues are specifically color management problems.  #34 
through #38 are definitely color management issues and #26 (spot color) may 
also be a color management issue.  #27 and #28 may be transparency issues but 
may also be impacted by color management.  

I think one goal for v 0.12 should be for poppler to be able to pass all (or 
maybe most) of the above tests. 

Hal

PS: Does anyone have a time frame for when my patches or derivatives of those 
patches will be applied to git?
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