[poppler] Patch proposal: Implementation for real gouraud shaded triangles
Christian Feuersaenger
cfeuersaenger at googlemail.com
Fri Oct 8 13:23:07 PDT 2010
Am 07.10.2010 23:08, schrieb Albert Astals Cid:
> A Dimecres, 6 d'octubre de 2010, Christian Feuersaenger va escriure:
>
>> Am 05.10.2010 22:59, schrieb Albert Astals Cid:
>>
>>> A Dijous, 30 de setembre de 2010, Christian Feuersaenger va escriure:
>>>
>>>> Hello Albert,
>>>>
>>>> Am 30.09.2010 00:00, schrieb Albert Astals Cid:
>>>>
>>>>> A Dijous, 19 d'agost de 2010, vàreu escriure:
>>>>>
>>>>>> Dear Albert,
>>>>>>
>>>>>> attached you find a test.pdf in which the improvements can be seen.
>>>>>>
>>>>>> The rendering quality of my patch is much better; it eliminates the
>>>>>> moire effects of the flat shading approximation (top left image).
>>>>>>
>>>>>> Compare also the image with opacity on page 2 of test.pdf.
>>>>>>
>>>>>> Besides the improved rendering quality, the most obvious change is the
>>>>>> required runtime: on my system, the default xpdf requires 15 seconds
>>>>>> until it stops rendering the first page whereas xpdf with poppler
>>>>>> support and my new patch requires about one second. The pdftoppm
>>>>>> utility is also considerably faster.
>>>>>>
>>>>>> Let me stress that the patch is unrelated to my previous bugfixes, so
>>>>>> rendering problems are only fixed together with the other bugfix.
>>>>>>
>>>>> I'm not sure i understand this last sentence, you say that the patches
>>>>> are
>>>>> unrelated but then you say the bugs are only fixed together with the
>>>>> other
>>>>> patch?
>>>>>
>>>>> Should i run a regression test over this patch or does it need to be in
>>>>> conjunction with the other patch?
>>>>>
>>>> The "Implementation for real gouraud shaded triangles" is more a new
>>>> feature than simply a bugfix: it re-implements the shaders for the
>>>> splash device. Its purpose is mainly a vastly improved rendering speed.
>>>> I'd suggest to run regression tests on this implementation separately
>>>> from my other patch proposals.
>>>>
>>>> The other patch proposals (you have processed them already; I still
>>>> have to investigate your problem report) are bug fixes which should be
>>>> tested separately.
>>>>
>>>> My last remark is to be understood as follows:
>>>> 1. if you view test.pdf with both patches, you have best quality and
>>>> highest speed.
>>>> 2. if you view test.pdf only with the given patch, you have high speed
>>>> and good quality for the triangle patches, but the coons patch things
>>>> will be buggy.
>>>> 3. if you only process the other patch proposal (the bugfixes which are
>>>> not part of mail), the coons patches are rendered correctly; but the
>>>> triangle patches are slow and only approximately correct due to the
>>>> piecewise flat triangle approximation as it is currently done in
>>>> libpoppler.
>>>>
>>>> I think the most reliable quality verification can be gained by testing
>>>> both patches separately.
>>>>
>>> Ok, i've ran the test regression over this aptch and everything seems to
>>> be ok, could you please fix the FIXME and TODO you have in the code?
>>>
>> Hello Albert,
>>
>> I'm glad the regression tests passed. Concerning the FIXME and TODO
>> list: They constitute (without exception) additional features which do
>> not limit the application of the patch (falling back to the old
>> implementations automatically). I am willing to work on the FIXMEs, but
>> a realization might not be finished before the beginning of the new year
>> due to my personal time schedule for the next months.
>>
>> I suggest to incorporate the patch into libpoppler as-is, and I will
>> work on the remaining feature requests eventually.
>>
> Not really, i want at least splashModeXBGR8 fixed (can can just try it with
> qt4/test/test-poppler-qt4) before commiting since is what the Qt frontend uses
> that is the major user of the Splash backend.
>
> I attach the patch as i tried.
>
> Albert
>
Ok, I'll attempt it. Thank you for the details.
Best regards
Christian
>
>> Best regards
>>
>> Christian
>>
>>
>>> Thanks,
>>>
>>> Albert
>>>
>>>> Best regards
>>>>
>>>> Christian
>>>>
>>>> PS
>>>> Sorry if you get notifications because of 'Post by non-member to a
>>>> members-only list'... I keep clicking onto the wrong email address :(
>>>> (have now registered both of them)
>>>>
>>>>
>>>>> Albert
>>>>>
>>>>>
>>>>>> Best regards
>>>>>>
>>>>>> Christian
>>>>>>
>>>>>> Am 18.08.2010 23:15, schrieb Albert Astals Cid:
>>>>>>
>>>>>>> A Dijous, 15 de juliol de 2010, Christian Feuersaenger va escriure:
>>>>>>>
>>>>>>>> Dear poppler developers,
>>>>>>>>
>>>>>>>> hereby I propose a new patch for a high quality, fast gouraud
>>>>>>>> shader for
>>>>>>>> triangle shadings.
>>>>>>>>
>>>>>>>> The patch provides
>>>>>>>> - scalable triangle shadings (in contrast to the old approach),
>>>>>>>> - correct shading, no approximation using flat triangles,
>>>>>>>> - greatly (!) improved rendering speed,
>>>>>>>> - support for opacity (in contrast to the previous approach).
>>>>>>>>
>>>>>>>> This patch is relative to the master branch,
>>>>>>>> git show poppler-0.14.0-91-g31ac578 .
>>>>>>>>
>>>>>>>> It is unrelated to my previous patch proposals concerning shadings;
>>>>>>>> the
>>>>>>>> other patch proposal (my mail several weeks ago) is still important
>>>>>>>> and
>>>>>>>> relevant. The patch in this mail is independent and does not
>>>>>>>> include my
>>>>>>>> previous patch proposals.
>>>>>>>>
>>>>>>>> I tested the new patch with pdftoppm and with the xpdf-poppler fork
>>>>>>>> of Rogerio Brito; it appears to work reliable. I tested
>>>>>>>> - matrix shadings and triangle patch shadings (Types 4 and 5),
>>>>>>>> - degenerated triangles,
>>>>>>>> - clipping,
>>>>>>>> - opacity,
>>>>>>>> - RGB color spaces.
>>>>>>>>
>>>>>>>> The implementation now supports these shadings on a display driver
>>>>>>>> level
>>>>>>>> and is implemented directly in the splash device (using scanline
>>>>>>>> sweeps).
>>>>>>>>
>>>>>>>> I've been defensive: I have no test cases for other color spaces and
>>>>>>>> I have no test data for non-parametric shadings. Consequently, I
>>>>>>>> disabled
>>>>>>>> the shader for these cases; it will fall back to the existing
>>>>>>>> solutions
>>>>>>>> (approximate shading by means of many flat triangles).
>>>>>>>>
>>>>>>>> I hope you find my patch proposal useful. I believe it is worthy of
>>>>>>>> being part of libpoppler.
>>>>>>>>
>>>>>>> Do you have a pdf where we can see the improvement this patch gives?
>>>>>>>
>>>>>>> Albert
>>>>>>>
>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Christian
>>>>>>>>
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