Add status returns to functions in order to propagate an error up
the call stack.
For the emit_*_pattern we add a new status return even when when
the functon return CAIRO_STATUS_SUCCESS unconditionally in order for
the caller to handle all cases in a consistent manner.
This adds a compiler check that the function result is used by the caller
and enables it by default for all cairo_private functions and for public
API that returns a cairo_status_t.
It has been discussed that to extend the warnings to all functions, a
new function type could been introduced to cover static functions:
cairo_static. This has not been done at the present time in order to
minimise the churn and focus on the more common errors.
In order to reduce the warning spew generated by gcc for invalid use of
this attribute, -Wno-attributes is added to CFLAGS. This has the
unfortunate side-effect of masking future warnings for all attributes -
be warned!
Reading the code, MAX_LEVEL is in fact what could have been named
MAX_NUM_LEVELS. That is, it is maximum possible level plus one.
All code is correct: it uses MAX_LEVEL as array size and never produces
a level of MAX_LEVEL. The comment is fixed.
Most of the time pixman_region_init is called without any extents, and
followed by a pixman_region_union_rect, used to used to initialize
rectangular regions. pixman_region_union_rect is not that cheap, but
the sequence is called quite often. So it should be worth introducing
a specialized and fast function for this sequence.
This introduces pixman_region_init_rect. This new function makes
_cairo_region_init_from_rectangle obsolete.
Also removes the extent argument from pixman_region_init as it was
called with NULL most of the time. A pixman_region_init_with_extents
is added for the general case.
This ensures that error due to double-to-float conversion
does not accumulate; the position of any glyph will be off by
at most one double-to-float conversion error.
Previously, a failure in _cairo_win32_scaled_font_init_glyph_path leading
to the CLEANUP_FONT label would set the path into the glyph, then destroy
the path, and return an error status, (which in turn would cause a double
free when the glyph was destroyed).
The double-free apparently leads to a crash in some cases, as described
here:
SVG/Cairo related crash when opening specific webpage
https://bugzilla.mozilla.org/show_bug.cgi?id=376498
This should eliminate the double-free, but does not address the original
error case, (attempting to get a path from a bitmap font?).
This is necessary to avoid many portability problems as cairoint.h includes
config.h. Without a test, we will regress again, hence add it.
The inclusion idiom for cairo now is:
#include "cairoint.h"
#include "cairo-something.h"
#include "cairo-anotherthing-private.h"
#include <some-library.h>
#include <other-library/other-file.h>
Moreover, some standard headers files are included from cairoint.h and need
not be included again.
Previously, the convention was that static ones started with cairo_, but
renamed to start with _cairo_ when they were needed from other files and
became cairo_private instead of static...
This is error prune indeed, and two symbols were already violating. Now
all nil objects start with _cairo_.
Frequently cairo_set_source_rgb[a]() is used to replace the current
solid-pattern source with a new one of a different colour. The current
pattern is very likely to be unshared and unmodified and so it is likely
just to be immediately freed [or rather simply moved to recently freed
cache]. However as the last active pattern it is likely to cache-warm and
suitable to satisfy the forthcoming allocation. So by setting the current
pattern to 'none' we can move the pattern to the freed list before we
create the new pattern and hopefully immediately reuse it.
Unfortunately one cannot cache live patterns and return a fresh reference
instead of creating new ones as patterns can be modified by the user and
so cannot be transparently shared between different users. However,
solid colour allocation is still a frequent operation, so we maintain a
small cache of recently freed patterns to reduce the malloc pressure.
