Carefully handle subsurfaces of a recording surface through the analysis
and paginated surfaces so that we can generate a native pattern for the
vector backends, demonstrated by the PostScript backend.
Nothing remarkable, just a lot of bookkeeping to track the wrapped
surface types and to apply the correct offsets when generating the
subsurface pattern.
cu found a bug when using clipping and fills with the image backend, but
it turns out to be the lost sign bug afflicting everything...
To trigger the bug requires evaluating the clip surface prior to using
in with _cairo_clip_combine_with_surface(). Which is taken along a
particular path when using a clip mask with non-pixel geometry on image,
but more easily hit by the fallback code.
Reported-by: <cairouser@yahoo.com>
This should exercise a bug found by Jeff Muizelaar that
cairo-surface-clipper was mistakenly thinking that clip operations on a
second context was a no-op as the topmost clip path matched that of the
previous context.
It was observed that we never actually test the condition that the
gradient is only defined for a portion of its range, i.e. the starting
offset is >0 and the ending offset is <0. By definition the colour
between 0 and start offset is the start color, so check that this
behaviour is followed by all backends.
Another bug identified by Jeff Muizelaar was that the bounds for a
zero-length (i.e. it started and stopped at the same point) were
miscomputed. This test case exercises that bug.
Note: I believe the output is wrong here when padding a zero-length
gradient. On the left it should be red, and on the right it should be
blue.
Jeff Muizelaar found a bug in _cairo_clip_init_copy() which was not
correctly propagating the all-clipped status when an empty clip was
saved in the gstate. This test case exercises that bug.
Having added a specialised scan converter on the premise that it should
be better at handling rounded rectangles, ensure that they are indeed
rendered correctly.
Enable origin tracking by default for make check-valgrind. This is
slower and consumes more memory than regular valgrind, but the
additional information provided about the source of the uninitialised
data is often invaluable.
A subsurface is a region of another surface that may be used either to
restrict the writable area of a context or the readable extents of a
source. Whilst writing, access to the exterior of the subsurface is
prevented via clipping and when used as a source reads from the exterior
of the subsurface are governed via the extend mechanism of the pattern.
Jeff reported a regression found by Mozilla whereby a uniform gradient
was not being premultiplied on conversion to a solid pattern.
https://bugzilla.mozilla.org/show_bug.cgi?id=539165
[Bug 539165] gradients with a single stop do not have their color
multiplied by the alpha.
Whilst investigating:
Bug 31788: SVG <line> with y1 == y2 and both with fractional
part don't render
https://bugs.webkit.org/show_bug.cgi?id=31788
I found that it can be reduced to a no-op clip following a no-op stroke
or fill. These conditions are exercised here and are shown to be a bug
introduced in the 1.9.x development series.
Compositing of alpha-only sources is not throughly tested and
as a consequence the misbehaviour of some backends is not
shown by the test suite.
[ickle: Added XFAILs for pdf, ps, svg.]
Otherwise, it was disrupting my attempts to release a snapshot, (since
it doesn't respect CAIRO_TEST_TARGET=" " and not run like most of the
tests do).
Hunting for a known bug in the xlib backend where it invalidly converts
an argb32 source to rgb24. However, this does not appear to be that bug,
but still a useful exercise nevertheless.
Now that we use polygon clipping, output geometry should no longer exceed
the 2^16 limits imposed by pixman. For the image backend, we now use spans
for stroking and for the xlib backend we have to double check the range on
the output trapezoids. In short, cairo should pass this test.
