[poppler] Patch proposal: Implementation for real gouraud shaded triangles

[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