| Age | Commit message (Collapse) | Author |
|---|
|
In an effort to solve bug 692377, examine what ghostscript does,
and move mupdf into line with it.
Firstly, it seems that rather than collecting a pure 'shape' plane
ghostscript keeps a 'shape-with-alpha' plane. Only a tiny change is
required to move mupdf to the do the same thing, so done here.
Secondly, it seems that ghostscript 'uncomposites' the result of
non-isolated groups, before applying the blend mode. It's not clear
to me that this is entirely correct; this 'uncomposite' operation
assumes that all compositing has been done internally with the
'normal' blend mode. Nonetheless, I do the same here, and it seems
to work.
This 'uncomposite' operation may yet turn out to be a source of bugs
if I have muddled the use of premultiplied and non-premultiplied
components, but it seems to work on the testfiles I have.
|
|
A combination of constant alpha and non-zero blending modes resulted
in incorrect rendering.
Various fixes seem to have made it work:
* Allow for non-full alpha when blending non-isolated groups back.
* Clamp blended pixels to allow for overflow.
* Allow for alpha in the shape blending.
|
|
Firstly, this takes on some of Zenikos patch to correct the clip
stack handling that was broken by the fix to bug 692287 (in commit
2c3bbbf). This bug should now be solved.
We add a new 'shape' field to the draw device structure (and clip
stack). When we are inside non-isolated groups, this is set to be
a pixmap where we accumulate the 'shape' of the objects drawn.
When we come to blend back, if we are blending a non-isolated group
back, we have to use a different blending function that takes account
of the shape.
Various internal groups (the page group, and groups used to force
blending) are set to be isolated to avoid carrying shape planes
around when this is not required.
All our rendering code now has to know how to maintain the shape
plane as well as doing the basic rendering.
|
|
|
|
Also put the function on the same line for inline functions, so
they stick out and are easy to find with grep.
|
|
The run-together words are dead! Long live the underscores!
The postscript inspired naming convention of using all run-together
words has served us well, but it is now time for more readable code.
In this commit I have also added the sed script, rename.sed, that I used
to convert the source. Use it on your patches and application code.
|
|
|
