[poppler] Implemented Type 4/5 shading for Splash Device

[Christian Feuersaenger]

Dear Poppler Developers,

attached you find my bugfix proposal to improve rendering of Type 4/5 
Shadings (Gouraud Interpolated Triangle Shadings).

What it does is:
1. implement the Function lookup to fix buggy display of parameterized 
shadings,

2. Improve the triangle refinement control such that it runs 5 times faster,

3. Share path memory between successive flat triangles which gains 
another 10% runtime improvement (avoids many new/delete operations).

I believe the changes are stable and should work without problems. The 
attached patch file patches against branch poppler-0.14 . Note that I 
changed the access policies to GfxSubPath: it has no setter methods 
which allows to re-use the same path with different coordinates (Point 3 
of the list above).

Looking forward to your opinions,

best regards

Christian

PS
I will send patch files for the implemented draft of *real* gouraud 
interpolated shadings when they become more or less stable.



Am 14.06.2010 23:07, schrieb Albert Astals Cid:
> A Dilluns, 14 de juny de 2010, Christian Feuersaenger va escriure:
>> Hi Albert,
>>
>> thank you for the fast reply and your positive answer!
>>
>> I will use the next days to apply the xpdf patches to libpoppler.
>>
>> I intent to patch the patched triangle refinement to your stable branch,
>> which appears to be the poppler-0.14 (?). I consider it to be a bugfix.
>
> Right poppler 0.14 is our stable branch.
>
>>
>> The interpolated shader is not yet stable and may need some revisions. I
>> will continue working on it, preferrable on a separate branch.
>> If you like, I can try to make a www git repository somewhere such that
>> you can fetch my changes and merge them to whereever you want.
>
> Personally i'd prefer that you send the patches to the mailing list, makes
> easier for more people to see them and comment if they feel like.
>
> Albert
>
>>
>> For the moment, you find my test.pdf attached. it has been generated
>> with latex and the unstable version of \usepackage{pgfplots},
>> http://pgfplots.sourceforge.net/; I also attached the .tex sources.
>>
>> So, thank you for the positive feedback.
>>
>> Best regards
>>
>> Christian
>>
>>   >>  >   I am sure my additions are valueable and propose them for usage in
>>   >>  >   libpoppler: the bugfix/speed improvement is directly usable and
>>
>> stable
>>
>>   >>  >   and the lowlevel shader will need some more time. I could also
>>
>> use some
>>
>>   >>  >   advice to get the integration with transparency, blending and
>>
>> whatever
>>
>>   >>  >   correctly. I started with the xpdf sources, so I would also
>>
>> appreciate
>>
>>   >>  >   any hints how you communicate changes between xpdf and libpoppler
>>
>> if you
>>
>>   >>  >   are interested in my proposal.
>>   >
>>   >  Yes, we are interested in your patches, basically what we would need
>>
>> you is to
>>
>>   >  provide a patch over poppler sources, you can choose wheter you want
>>
>> to make
>>
>>   >  it against git master branch, git poppler-0.14 branch or the released
>>
>> 0.14.0
>>
>>   >  tarball.
>>   >
>>   >  Also it would be interesting to have the PDF you have used for testing.
>>   >
>>   >  Thanks,
>>   >
>>   >     Albert
>>
>> _______________________________________________
>> poppler mailing list
>> poppler at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/poppler
> _______________________________________________
> poppler mailing list
> poppler at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/poppler

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