We detect an error in the surface before calling into private surface-modifying
functions, (such as _cairo_surface_set_font_options), that don't have the
nil-surface protection of public functions.
This should fix the problem reported (again) in this bug report:
cairo crashes in cairo_create_simular if nil surface returned by other->backend->create_similar
https://bugs.freedesktop.org/show_bug.cgi?id=9844
Though I haven't succeeded in replicating the bug yet, (perhaps a system
difference in allowing writes to read-only memory or not, or something
like that).
When a single function accepts pointers for multiple return values,
the convention is that it's legal for the user to pass NULL for
those pointers in case the user is only interested in some subset
of the values.
This was already properly implemented for functions such as
cairo_pattern_get_rgba, etc.
Here we fix four functions to follow the same convention:
cairo_stroke_extents
cairo_fill_extents
cairo_clip_extents
cairo_surface_get_device_offset
On some architectures, gcc will emit a memcpy for structure copies which will
produce a valgrind warning when the source and destination pointers are the
same. Workaround this issue by explicitly checking the source and destination
for inequality before doing the structure assignment.
This reverts the following commits:
2715f2098167e3b3c53b
See this thread for an analysis of the problems it caused:
http://lists.freedesktop.org/archives/cairo/2007-February/009825.html
In short, a single cache for all backends doesn't work, as one thread
using any backend can cause an unused xlib pattern to be evicted from
the cache, and trigger an xlib call while the display is being used
from another thread. Xlib is not prepared for this.
for surface patterns.
Right before releasing cairo 1.2, Carl and I decided to return error on
CAIRO_EXTEND_PAD and CAIRO_EXTEND_REFLECT for surface patterns, as they
are not implemented and one was causing crashes. Well, that was probably
the worst decision we could make (other than ignoring the problem). A
much better decision would have been to make them act like
CAIRO_EXTEND_NONE and CAIRO_EXTEND_REPEAT respectively. Anyway, remove
the error paths.
Previous commit broke cairo_surface_finish, since it was checking for
ref_count == CAIRO_REF_COUNT_INVALID and bailing. But, that condition
was reached from destroy, so finish was bailing out early.
user_data setters/getters were added to public refcounted objects
that were missing them (cairo_t, pattern, scaled_font). Also,
a refcount getter (cairo_*_get_reference_count) was added to all
public refcounted objects.
We use a small cache of size 16 for surfaces created for solid patterns.
This mainly helps with the X backends where we don't have to create a
pattern for every operation, so we save a lot on X traffic. Xft uses a
similar cache, so cairo's text rendering traffic with the xlib backend
now completely matches that of Xft.
The cache uses an static index variable, which itself acts like a cache of
size 1, remembering the most recently used solid pattern. So repeated
lookups for the same pattern hit immediately. If that fails, the cache is
searched linearly, and if that fails too, a new surface is created and a
random member of the cache is evicted.
Only surfaces that are "compatible" are used. The definition of compatible
is backend specific. For the xlib backend, it means that the two surfaces
are allocated on the same display. Implementations for compatibility are
provided for all backends that it makes sense.
A cairo_scaled_font_t can be implicitly shared among multiple threads
as the same cairo_scaled_font_t can be returned from different calls
to cairo_scaled_font_create. To retain the illusion that these
different calls produce distinct objects, cairo must internally lock
access when modifying them.
Each glyph in the scaled font is represented by a cairo_surface_t
which is used when rendering the glyph. Instead of attempting to push
fine-grained locking of these surfaces down to the backend rendering
functions, a simple per-cairo_scaled_font_t lock has been introduced
which protects the entire rendering path against re-entrancy.
Some care was required to ensure that existing re-entrancy was handled
appropriately; these cases are in the wrapping surfaces
(cairo-paginated, test-meta and test-paginated).
Thanks to Vladimir Vukicev and Peter Weilbacher for testing/providing
the mutex definitions for win32 and os2 (respectively).
Calling cairo_surface_finish from cairo_surface_destroy was
triggering an error due to finish being called twice. The
error was usually hidden as the surface would still eventually
be destroyed. But it did clutter things up quite badly if a
user was trying to break on _cairo_error to track down a
problem.
Thanks again to Stuart Parmenter <stuartp@gmail.com>
for pointing out the problem.
The rule is: cairo_glyph_t* is always passed as const for measurement
purposes. This was not reflected in our public api previously. Fixed
Showing glyphs used to have cairo_glyph_t* always as const. With this
changed, it is only const on cairo_t and cairo_gstate_t operations.
cairo_surface_t, cairo_scaled_font_t, and individual backends receive
cairo_glyph_t* as non-const. The desired semantics is that they may modify
the contents of the array as long as they do not return
CAIRO_STATUS_UNSUPPORTED. This makes it possible to avoid copying the glyph
array again and again, and edit it in-place. Backends are in fact free to use
the array as a generic buffer as they see fit.
This fixes a huge performance bug (entire image was being pushed to X
server in order to copy a tiny piece of it). I see up to 50x improvement
from subimage_copy (which was designed to expose this problem) but also
a 5x improvement in some text performance cases.
xlib-rgba subimage_copy-512 3.93 2.46% -> 0.07 2.71%: 52.91x faster
███████████████████████████████████████████████████▉
xlib-rgb subimage_copy-512 4.03 1.97% -> 0.09 2.61%: 44.74x faster
███████████████████████████████████████████▊
xlib-rgba subimage_copy-256 1.02 2.25% -> 0.07 0.56%: 14.42x faster
█████████████▍
xlib-rgba text_image_rgb_over-256 63.21 1.53% -> 11.87 2.17%: 5.33x faster
████▍
xlib-rgba text_image_rgba_over-256 62.31 0.72% -> 11.87 2.82%: 5.25x faster
████▎
xlib-rgba text_image_rgba_source-256 67.97 0.85% -> 16.48 2.23%: 4.13x faster
███▏
xlib-rgba text_image_rgb_source-256 68.82 0.55% -> 16.93 2.10%: 4.07x faster
███▏
xlib-rgba subimage_copy-128 0.19 1.72% -> 0.06 0.85%: 3.10x faster
██▏
New internal function _cairo_surface_set_font_options is used to set them.
cairo_surface_create_similar propagates the font options of the other
surface into the newly created surface. Fixes bugs with font options in
fallback images and bug 4106.
Fixes the bug that paginated backends had font-matrix translation
applied twice, AND removes a second copy of the glyphs. It's
essentially similar to what cworth did for stroke/fill/clip in
this commit: bd92eb7f3c
Reviewed by: Carl Worth
As the font matrix includes translation, which is otherwise unused for glyph
transformation, the interpretation of translation is fairly arbitrary. For
1.2.0, we choose to have this translation affect the glyph advance with the
thought that it could be used to do letter spacing/kerning. That is fairly
useless in practice, and a far more useful interpretation is to relocate
the origin of each glyph.
This patch uses the translation in the font matrix as an offset for the
glyph origin in user space. It turns out glyph extents were already correctly
shifted.
The end result with this patch is to have cairo match the 1.0 behaviour for
font matrix translations, but now we know why :-)
Explanation above courtesy of Keith Packard.
This is an attempt to fix the following bug:
http://bugzilla.gnome.org/show_bug.cgi?id=332266
With the recent rewrite of the device-offset code, which pushed things
from the gstate to the surface layer, the 16-bit limitations on coordinates
which previously applied to device space only, have lately been applying to
user space. This commit moves the device_transform back up above the conversion
from floating-point to fixed-point values so that once again the limitation
only applies to device space.
Previously this function was attempting to return values in surface
space, (but even then it was doing it wrong). However, all callers
actually expect values in backend space. Fixing this cleans up bug
7268 quite nicely.
The aliases should allow binaries with the old symbols to continue to run.
Meanwhile, the macros in cairo.h prevent any code from being compiled without
using the new, future-proof function names.
This is a temporary, transition strategy and the aliases will be dropped
before the next major release.
The old behavior of returning "infinite" extents is inconsistent with
the current usage of meta-surface where it is always created for
replay against a particular (sized) target surface and that size is
passed to _cairo_meta_surface_create.
Also clarify documentation of _cairo_surface_get_extents to eliminate
the possibility of inifinite extents.
(This is covering up my mistake from the last batch of 12 commits which
wasn't ready to be pushed yet. This fixes some of the crashes which
were introduced, and is a good thing to do regardless.)
The trick is to create a new scaled_font with the device_transform
multiplied into the CTM within _cairo_surface_show_glyphs before
calling into the backend. The fallback-resolution test shows that
the font size is now correct.
The trick is to simply multiply the device_transform into the CTM
within _cairo_surface_stroke before passing the CTM down to the
backend. The fallback-resolution test shows that the stroke width is
now correct.
Add new, private _cairo_surface_set_device_scale for getting at the
scaling components of device_transform. Use this in paginated surface
when replaying to an image surface. The fallback-resolution test now
clearly shows that image fallback resolution can be controlled by the
user. Hurrah!
