func_regexp was incorrectly complaining that cairo_pure was a function without
parenthesis. The simplest solution appeared to be allow quoting of
'cairo_pure'.
As is so often the case, reading the commit log gives you fresh insight in
the problem - often called confessional debugging...
We can simplify the problem by ignoring attr->[xy]_offset, for the time
being, and focus on computing the correct matrix. This is comparatively
simple as all we need to do is perform the appropriate rounding on the
translation vector.
A complication I realised after pushing 3eb4bc3 was handling larger
sampled areas. Extending the test case revealed that the optimization
was broken for anything but the identity transform (after removing the
translation). Correctness first, leaving the "pixel-exact" solution for
interested reader...
Carl suggested that cairo_pure and cairo_const are pretty opaque, even to
the developer who added them, so it is extremely important that they have
a good description so that they are used correctly and perhaps ported to
other compilers.
With the addition of cairo_show_text_glyphs() came a couple of functions
to query whether the target supported the extended attributes. However,
at Carl's request cairo_has_show_text_glyphs() was removed - but the
documentation was not updated to reflect that.
As identified in bug 15479,
Unpredictable performance of cairo-xlib with non-integer translations of a
source surface pattern
(https://bugs.freedesktop.org/show_bug.cgi?id=15479),
source surfaces with a fractional translation hit slow paths for some
drivers, causing seemingly random performance variations. As a work-around
Owen Taylor proposed that cairo could convert non-integer translations on
NEAREST sources patterns to their integer equivalents.
The messy detail involved here is replicating the rounding mode used by
pixman for the sample offset, but otherwise the conversion is fairly
trivial.
As proof-of-principle, compute a scale factor to avoid overflow when
converting a linear pattern to pixman_fixed_t. Fixes test/huge-pattern,
but the principle should be extended to handle more cases of overflow.
Bulia Byak reported a bug where cairo was crashing with a particular
font. The font had an incorrect entry in the cmap table that caused
cairo to read from outside of the buffer allocated for the cmap.
Bug 11734:
XRender crashes due to NULL pointer from Cairo on SGI O2
(https://bugs.freedesktop.org/show_bug.cgi?id=1173)
is an example of a case where we try to perform an XRender operation on a
surface with a format that was not supported by the XRender extension. By
marking the extension version as -1 on those surfaces, the current checks
for SURFACE_RENDER_HAS_* always correctly return false and prevent us try
to create a Picture with a NULL xrender_format.
Since cairo.h is a public header file, we need to be careful so that it
can be compiled by random compilers and even users specifying "-Werror
-Wundef" (mentioning no names, Company). So replace the bare (and legal)
#if _MSC_VER
with
#if defined (_MSC_VER)
just in case.
Missed updating win32 when implementing the new paginated API to query
support for the fine-grained fallbacks.
(Thanks to Adrian for spotting this oversight.)
The use of fine-grained fallbacks requires the native support of the
SOURCE operator applied to an image on the target surface. SVG 1.2
introduces the "comp-op:src" mode fulfilling this criteria - so we can
enable fine-grained fallbacks for 1.2+.
Update test/fine-grained-fallbacks to exercise this pathway in SVG 1.2 -
as SVG natively supported all the current operations within that test.
This reveals yet another librsvg bug in handling SVG 1.2.
Avoid passing a 32bit integer as a cairo_int64_t in case we do not have a
64bit native integral type. As a side-effect this means we can also use a
narrower multiply.
For the simple case where the pattern matrix only contains an integer
translation then care is taken to convert that to a identity source matrix
with the translation applied to the [xy]_offsets. 5b97ee6525 broke this
guarantee by applying the clone offsets to the source matrix. So when the
source matrix is identity we can simply adjust the [xy]_offsets and
preserve the identity matrix. (This idea can be extended further by
removing any integer translation from the source matrix and storing it in
the [xy]_offsets as a means to extend the limited precision in
pixman_matrix_t - encountered when downscaling large images offset onto
the target surface.)
A precondition for using the core XCopyArea protocol is that the source
attributes contain only integer translations. However, we failed to apply
any integer translations from the source matrix to the XCopyArea offsets.
This worked prior to 5b97ee6525 as
_cairo_pattern_acquire_surface_for_surface() was careful to only generate
an identity matrix if the pattern matrix only contained an integer
translation (and thus we would use XCopyArea in the xlib backend).
gtk-doc fails make check for array as it insists that even the simplest
functions must have a long description and cannot be entirely described by
their arguments and return value.
During insertion we must traverse the skiplist in order to find the
insertion point for the new element. As we descend each level, the next
element in the chain for this level is sometimes the same as the one we
just compared against (and know that the new element is greater than).
Hence we can skip the search on that level and descend to the next. During
world_map this reduces the number of calls into _sweep_line_elt_compare()
by ~2.5% (and when performing trapezoidation on strokes gives a similar
speed up of about 2% - not bad for the addition of a single line.)
Use primitives from cairo-wideint-private.h - in this case it helps to
make the code more readable as well as reduce dependence on native 64bit
integers.
Prefer to use the operations form cairo-wideint-private.h in order to
improve readability and reduce our assumptions on the availability of
64bit integers.
'const' is a stricter form of 'pure' in that functions declared with that
attribute do not access any values other than their arguments (in
contrast to 'pure' which is allowed to read from global memory).
Take advantage of the gcc function attribute 'pure', which tells gcc that
the function result only depends upon its arguments and it has zero side
effects (e.g. it does not clobber memory). This gives gcc greater
opportunity to rearrange and optimize the wideint arithmetic.
We often use the construct:
if (_cairo_int64_lt (A, B)
return -1;
if (_cairo_int64_gt (A, B)
return 1;
return 0;
to compare two large integers (int64, or int128) which does twice the
required work on CPUs without large integer support. So replace it with a
single wideint function _cairo_int64_cmp() and therefore allow
opportunities to both shrink the code size and write a more efficient
comparison. (The primarily motivation is to simply replace each block with
a single more expressive line.)
If the sweep-line is currently on an end-point of a line,
then we know its precise x value and can use a cheaper comparator.
Considering that we often need to compare events at end-points (for
instance on a start event), this happens frequently enough to warrant
special casing.
We need to compare the x-coordinate of a line at a for a particular y,
without loss of precision.
The x-coordinate along an edge for a given y is:
X = A_x + (Y - A_y) * A_dx / A_dy
So the inequality we wish to test is:
A_x + (Y - A_y) * A_dx / A_dy -?- B_x + (Y - B_y) * B_dx / B_dy,
where -?- is our inequality operator.
By construction we know that A_dy and B_dy (and (Y - A_y), (Y - B_y)) are
all positive, so we can rearrange it thus without causing a sign
change:
A_dy * B_dy * (A_x - B_x) -?- (Y - B_y) * B_dx * A_dy
- (Y - A_y) * A_dx * B_dy
Given the assumption that all the deltas fit within 32 bits, we can compute
this comparison directly using 128 bit arithmetic.
The convex_quad tessellator (and possibly even the more general polygon
tessellator) will generate empty trapezoids when given a
rectangle which can be trivially discarded before inserting into traps.
Move the predicate for starting a new glyph elt into a macro so that it
can be shared between _cairo_xlib_surface_emit_glyphs() and
_emit_glyph_chunks() without code duplication.
_cairo_xcb_surface_is_similar() is currently only used by the pattern
cache to determine whether to keep the surface in the solid color cache.
This is fundamentally broken without hooking into Display closure as it
keeps a reference to an expired picture. So in order to prevent spurious
application crashes, disable the caching for xcb.
As reported by Damian Frank:
"I ran into a hitch with the Makefile.win32 infrastructure. It uses -MD and
-LD when linking regardless of the config, but it should be using -MDd and
-LDd for the debug config. I believe both the Makefile.win32.common and
src/Makefile.win32 files include erroneous declarations. This produces
warnings at link time about a mismatch when linking against properly created
debug libs (for instance, I had a zlib built as "LIB ASM Debug" that linked
properly against the debug runtime).
This problem applies to pixman too; can you pass this along to the
maintainer?"
Would be delighted to if someone commits a fix to pixman reading this
commit message.
