[poppler] Followup Bug 32349 & Poppler: More shading fun ;-)

[Andrea Canciani]

On Fri, Dec 31, 2010 at 3:10 AM, Thomas Freitag
<Thomas.Freitag at kabelmail.de> wrote:
> I made a lot of mistakes, but I'm quite close now, s. attached rendering of
> Andrea's PDF. What is still up to do, is

Wow, that's really good!

> a) speed it up again
> b) implement the shading extend in a correct way (I'd already a look at it,
> it's also wrong implemented in Gfx)
> c) run it again through my own regression test.

I'd like to provide another set of "difficult" radial gradients,
because the test
I posted isn't checking some interesting cases (in particular the case where
start and end circle are tangent):
http://people.freedesktop.org/~ranma42/cairo/radial/

This folder contains some pdf files and the expected rasterization.
Adobe Reader seems to be unable to display these files (it just hangs),
so I also created some "reduced" versions:
http://people.freedesktop.org/~ranma42/cairo/radial/

Adobe Reader can display the reduced files, but all of them look incorrect
in the second column (start circle tangent inside end circle).

>
> But first I need a little bit to sleep :-)

Sorry for trying so hard to make your code fail ;P
FWIW I'm doing the same against my own radial gradient implementation
in pixman (which right now fails with tangent circles, but I already have a
patch to fix it).

Andrea

>
> Thomas
>
> Am 30.12.2010 12:20, schrieb Thomas Freitag:
>>
>> I just recognized a bug with Andrea's PDF when drawing non centered
>> circles. Want to fix that first before sending a new patch.
>>
>> Thomas
>>
>> Am 30.12.2010 11:29, schrieb Albert Astals Cid:
>>>
>>> A Dijous, 30 de desembre de 2010, vàreu escriure:
>>>>
>>>> Sorry, I attached Your "new.png", not mine. Here the correct one
>>>> produced with the above changes.
>>>
>>> This looks good enough for me, can you send the full patch to the list?
>>>
>>> Thanks!
>>>
>>> Albert
>>>
>>>> Thomas
>>>>
>>>> Am 30.12.2010 10:31, schrieb Thomas Freitag:
>>>>>
>>>>> Hi Albert!
>>>>>
>>>>> I changed the SplashRadialPattern::getColor a little bit to solve
>>>>> this. It is still a little bit different from the old one, in my
>>>>> opinion a little bit better, but that's just a flavour, and in other
>>>>> cases it could be a little bit more worse. So if You agree, I can send
>>>>> a complete new patch.
>>>>>
>>>>> BTW, as You probably see, Andrea attached his PDF to the closed bug
>>>>> 32349. I saw already yesterday, that also the new rendering with the
>>>>> latest patch is quite better than the old rendering, but it's still
>>>>> not shown what Acrobat reader shows. I'll have an additional look in
>>>>> it, but I fear that this will be again a bigger job (the PDF has 128
>>>>> radial shadings, and only some of them are still buggy!). So (if not
>>>>> solvable in time) I would prefer to close this thread first, and then
>>>>> reopen the bug or create a new one.
>>>>>
>>>>> Do You agree, or do You have other ideas?
>>>>>
>>>>> Thomas
>>>>>
>>>>> FYI, here the changes:
>>>>>
>>>>> GBool SplashRadialPattern::getColor(int x, int y, SplashColorPtr c) {
>>>>>
>>>>>   double xc, yc;
>>>>>   int xs, ys;
>>>>>   Guchar *bitmapAlpha;
>>>>>
>>>>>   bitmapAlpha = bitmap->getAlphaPtr();
>>>>>   ictm.transform(x, y,&xc,&yc);
>>>>>   xs = splashRound(xc);
>>>>>   ys = splashRound(yc);
>>>>>   // Because of rounding problems, coordinates could be
>>>>>   // outside the bitmap. Reset them on the outer bound now
>>>>>   // and let it up to the alpha channel if they are shown:
>>>>>   if (xs<  0) xs = 0;
>>>>>   if (xs>= bitmap->getWidth()) xs = bitmap->getWidth() - 1;
>>>>>   if (ys<  0) ys = 0;
>>>>>   if (ys>= bitmap->getHeight()) ys = bitmap->getHeight() - 1;
>>>>>   if (bitmapAlpha[ys * bitmap->getWidth() + xs])
>>>>>
>>>>>       bitmap->getPixel(xs, ys, c);
>>>>>
>>>>>   else
>>>>>
>>>>>       return gFalse;
>>>>>
>>>>>   return gTrue;
>>>>>
>>>>> }
>>>>>
>>>>> Am 29.12.2010 23:28, schrieb Albert Astals Cid:
>>>>>>
>>>>>> First page, left of the "title". A few white pixels in there.
>>>>>>
>>>>>> Albert
>>>>>>
>>>>>> A Dimecres, 29 de desembre de 2010, Thomas Freitag va escriure:
>>>>>>>
>>>>>>> Am 29.12.2010 18:53, schrieb Andrea Canciani:
>>>>>>>>
>>>>>>>> On Wed, Dec 29, 2010 at 4:48 PM, Thomas Freitag
>>>>>>>>
>>>>>>>> <Thomas.Freitag at kabelmail.de>    wrote:
>>>>>>>>>
>>>>>>>>> ...
>>>>>>>>> I made a mistake when solving the problem with
>>>>>>>>> altona_visual_1v2a_x3.pdf. I find now a better way to solve it,
>>>>>>>>> which
>>>>>>>>> also gives a better look of the printer paper back again.
>>>>>>>>
>>>>>>>> I'd like to point yo to another pdf whose rendering regresses with
>>>>>>>> the
>>>>>>>> patch: https://bugs.freedesktop.org/attachment.cgi?id=41506
>>>>>>>
>>>>>>> Albert, can You please just change two lines in the former patch?
>>>>>>> 1. In SplashOutputDev.cc in the constructor of SplashRadialPattern,
>>>>>>> replace
>>>>>>> + bitmap = new SplashBitmap(splashRound(width) + 1,
>>>>>>> splashRound(height)
>>>>>>> + 1, colorMode != splashModeMono1, colorMode, gTrue);
>>>>>>> through
>>>>>>> +      bitmap = new SplashBitmap(splashRound(width) + 2,
>>>>>>> splashRound(height) + 2, colorMode != splashModeMono1, colorMode,
>>>>>>> gTrue);
>>>>>>> 2. In Splash.cc in the painting routine radialShadedFill, where the
>>>>>>> smaller extend circle is painted, replace
>>>>>>> + drawPartEllipseLine(&pipe, 2* yo - curY, xMin, xMax);
>>>>>>> through
>>>>>>> +                drawPartEllipseLine(&pipe, curY, xMin, xMax);
>>>>>>> (curY is alfready recalculated two line before!)
>>>>>>>
>>>>>>> Or just reapply the attached patch.
>>>>>>> This solves the rendering regressions mailed by Andrea.
>>>>>>>
>>>>>>> Thomas
>>>>>>>
>>>>>>>> In the last row, half of the inner circle is transparent with
>>>>>>>> poppler/master+radialsh.patch.
>>>>>>>>
>>>>>>>> Andrea
>>>>>>>>
>>>>>>>> PS: Sorry for removing most of the thread from this message, but
>>>>>>>> gmail
>>>>>>>> squashed it to just one level.
>>>>>>>> _______________________________________________
>>>>>>>> poppler mailing list
>>>>>>>> poppler at lists.freedesktop.org
>>>>>>>> http://lists.freedesktop.org/mailman/listinfo/poppler
>>>>>>>>
>>>>>>>> .
>>>
>>> .
>>>
>>
>
>