The test for opaque gradients in _cairo_pdf_surface_add_pdf_pattern()
must be identical to the test in
_cairo_pdf_surface_emit_pattern_stops() other wise the PDF file will
reference a smask that does not exist.
The _cairo_pattern_is_opaque() test is too strict for PDF as PDF can
draw EXTEND_NONE gradients with opaque color stops without requiring a
smask.
What we want to use is size_t, but we don't want the implied POSIX
dependency. However, POSIX does say that size_t is an unsigned integer
that is no longer than a long, so it would appear safe to use an
unsigned long as a replacement. Safer at least than unsigned int.
I did this manually so I could review the docs at the same time.
If anyone finds typos or other mistakes I did, please complain to me (or
better: fix them).
Previously the glyph advance in font units was used for the widths in
the PDF font dictionary. This only works for cff fonts that use a
[0.001 0 0 0.001 0 0] font matrix.
Previously the glyph advance in font units was used for the widths in
the PDF font dictionary. This only works for Type 1 fonts that use a
[0.001 0 0 0.001 0 0] font matrix.
https://bugs.freedesktop.org/show_bug.cgi?id=28061
Hopefully reduce the occurrence of the confusion between the
premultiplied shorts in cairo_color_t and the non-premultiplied shorts
in cairo_color_stop_t.
The existence of the two separate types is debatable and open for
review.
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.
I updated the Free Software Foundation address using the following script.
for i in $(git grep Temple | cut -d: -f1 )
do
sed -e 's/59 Temple Place[, -]* Suite 330, Boston, MA *02111-1307[, ]* USA/51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA/' -i "$i"
done
Fixes http://bugs.freedesktop.org/show_bug.cgi?id=21356
The device is a generic method for accessing the underlying interface
with the native graphics subsystem, typically the X connection or
perhaps the GL context. By exposing a cairo_device_t on a surface and
its various methods we enable finer control over interoperability with
external interactions of the device by applications. The use case in
mind is, for example, a multi-threaded gstreamer which needs to serialise
its own direct access to the device along with Cairo's across many
threads.
Secondly, the cairo_device_t is a unifying API for the mismash of
backend specific methods for controlling creation of surfaces with
explicit devices and a convenient hook for debugging and introspection.
The principal components of the API are the memory management of:
cairo_device_reference(),
cairo_device_finish() and
cairo_device_destroy();
along with a pair of routines for serialising interaction:
cairo_device_acquire() and
cairo_device_release()
and a method to flush any outstanding accesses:
cairo_device_flush().
The device for a particular surface may be retrieved using:
cairo_surface_get_device().
The device returned is owned by the surface.
As a simple step to ensure that we do not inadvertently modify (or at least
generate compiler warns if we try) user data, mark the incoming style
and matrices as constant.
PDF requires a '\n' between the end of stream data and the "endstream"
that is not included in the stream length. Ensure this is always added
in _close_stream where it is not included in the stream length.
Previously the jpeg/jp2 embedding functions were adding the '\n'. This
resulted in the '\n' becoming part of the stream data.
Within our code base we carried a few hacks to utilize the component
alpha capabilities of pixman, whilst not supporting the concept for our
own masks. Thus we were setting it upon the pixman_image_t that we
passed around through code that was blissfully unaware and indeed the
component-alpha property was forgotten (e.g. upgrading glyph masks).
The real issue is that without explicit support that a pattern carries
subpixel masking information, that information is lost when using that
pattern with composite. Again we can look at the example of compositing
a sub-pixel glyph mask onto a remote xlib surface for further failure.
If we have to rasterise a pattern for use by PS/PDF (for example, to
satisfy CAIRO_EXTENT_PAD) then only generate an image large enough to
cover the operation extents. We ensure tight coverage by computing the
extents afresh - we could do this lazily in the future, but we can not
rely on the bounds as computed by the analysis surface as for native
operations they may not be tight.
This is an optimization the PS surface has been using to improve
printing speed and prevent printers from choking on large
images. Applying this optimzation to PDF prevents the same problem
occuring when the PDF is converted to PS.
is_rectangle() is far stricter than is_box(), and is only required for a
very limited set of operations (essentially were the rectangle must
conform to the motion as described by cairo_rectangle). For the general
case where we just want to know whether we have a single rectangular path
that covers a certain area, is_box() is sufficient.
_cairo_pdf_surface_emit_to_unicode_stream() was reserving glyph 0 for
the .notdef glyph (as required by TrueType/CFF/Type1 fallback
fonts). However Type 3 fonts do not reserve glyph 0 for .notdef and
need glyph 0 to be included in the toUnicode stream.
http://lists.cairographics.org/archives/cairo/2009-July/017731.html
Handling clip as part of the surface state, as opposed to being part of
the operation state, is cumbersome and a hindrance to providing true proxy
surface support. For example, the clip must be copied from the surface
onto the fallback image, but this was forgotten causing undue hassle in
each backend. Another example is the contortion the meta surface
endures to ensure the clip is correctly recorded. By contrast passing the
clip along with the operation is quite simple and enables us to write
generic handlers for providing surface wrappers. (And in the future, we
should be able to write more esoteric wrappers, e.g. automatic 2x FSAA,
trivially.)
In brief, instead of the surface automatically applying the clip before
calling the backend, the backend can call into a generic helper to apply
clipping. For raster surfaces, clip regions are handled automatically as
part of the composite interface. For vector surfaces, a clip helper is
introduced to replay and callback into an intersect_clip_path() function
as necessary.
Whilst this is not primarily a performance related change (the change
should just move the computation of the clip from the moment it is applied
by the user to the moment it is required by the backend), it is important
to track any potential regression:
ppc:
Speedups
========
image-rgba evolution-20090607-0 1026085.22 0.18% -> 672972.07 0.77%: 1.52x speedup
▌
image-rgba evolution-20090618-0 680579.98 0.12% -> 573237.66 0.16%: 1.19x speedup
▎
image-rgba swfdec-fill-rate-4xaa-0 460296.92 0.36% -> 407464.63 0.42%: 1.13x speedup
▏
image-rgba swfdec-fill-rate-2xaa-0 128431.95 0.47% -> 115051.86 0.42%: 1.12x speedup
▏
Slowdowns
=========
image-rgba firefox-periodic-table-0 56837.61 0.78% -> 66055.17 3.20%: 1.09x slowdown
▏
The meta-surface is a vital tool to record a trace of drawing commands
in-memory. As such it is used throughout cairo.
The value of such a surface is immediately obvious and should be
applicable for many applications. The first such case is by
cairo-test-trace which wants to record the entire graph of drawing commands
that affect a surface in the event of a failure.
A trivial fix to reset the original surface size after emitting the group.
The annoying aspect is that this should have been caught by the test suite.
Alas, no. A gentle reminder that simple line coverage is insufficient. :(
