This patch adds the following API calls:
cairo_push_group
cairo_push_group_with_content
cairo_pop_group
cairo_pop_group_to_source
cairo_get_group_target
These methods support implementing layers on top of a cairo context,
allowing for drawing with transparency and temporary buffering.
cairo_get_group_target allows an app to get access to the actual surface
created by the last push_group call, in case itneeds to perform native
drawing to it.
This is a mega-patch that has the advantage that the entire test suite
passes both immediately before and immediately after this commit.
The disadvantage of the mega-patch is that it does not reflect the
development history of the device-offset branch, (with its various
fumblings and flailings). To capture that history, we will next merge
in that branch.
Shrink linear-gradient and text-pattern test outuput.
The real motivation for this is to hide an annoying difference in the
gradient output that occurs when under the influence of a device
offsets. My opinion is that the gradient output should not change due
to just an integer offset, but we currently don't have a precise
gradient specification, so this minor deviation really isn't relevant.
A better fix for this might have been to make the test suite more
forgiving of tiny differences, (perhaps on a per-test basis), but
another advantage of shrinking these tests is that they now run a lot
faster.
It is true that these tests now also exercise fewer different output
values, but that's not the designed purpose of the tests so I don't
feel bad about losing that characteristic.
[With this change, two tests with gradients exhibit subtle differences
under device offsets. I don't think we actually care about them
though. -cworth]
This commit adds the following new functions to the cairo-ps API:
cairo_ps_surface_dsc_comment
cairo_ps_surface_dsc_begin_setup
cairo_ps_surface_dsc_begin_page_setup
Many thanks are due to Michael Sweet who provided invaluble guidance
during the design of this API.
It is hoped that with this API in place, basically all printer control
that is likely to be desired to be performed with cairo PostScript
output is now possible.
This commit augments the ps-features test to exercise the new API.
Add a new cairo_ps_surface_set_size which can be used to produce a
PostScript file consisting of pages of various different sizes (or
orientations).
Also add a new test (ps-features.c) for testing this and subsequent
ps-specific function calls.
In several cases the -rgb24 reference images were identical to the -ref images.
So we change the logic to find the latter if the former doesn't exist, and then
we remove the redundant images.
Add a new cairo_test_paint_checkered function so that tests that draw
with alpha can easily put an easy-to-see checkered background in place
first.
Add new tests caps-joins-alpha and paint-source-alpha that do simple
tests of strokes and image painting with source pattern alpha.
Also, add the checkered background to paint-with-alpha for
consistency.
It only fails because the PDF ouput doesn't preserve the NEAREST filter attribute.
There might be a way to get something like this in the PDF, but it's not the point
of the test.
Some tests were using source surfaces created as ARGB32 even though all
alpha values are entirely opaque. This meant these tests were triggering
more fallbacks than strictly necessary for what the tests are ttrying to
do.
This isn't very exciting text output---it simply turns every call to
cairo_show_glyphs into a single filled path. But at the very least,
text will no longer trigger image fallbacks for the PDF backend.
With this commit, the following tests change from all-fallback to
all-native for the PDF backend:
show-text-current-point
text-antialias-gray
text-antialias-none
text-antialias-subpixel
text-cache-crash
text-rotate
There are rasterization differences in the output (cairo vs. freetype)
so this commit also adds new PDF-specific reference images for some of
those tests so that the suite continues to report PASS.
That helps SVG backend to pass this test, since CAIRO_OPERATOR_CLEAR on a part of a surface use "comp-op" element which is not supported with current librsvg.
Antialias property is not directly supported by SVG, and probably not the most wanted feature. In the future, we could use an image fallback in order to emulate it, or try to use text-rendering, shape-rendering and image-rendering
properties (http://www.w3.org/TR/SVG/painting.html#RenderingProperties).
