Currently glyphs are cached independently in each font i.e. each font
maintains a cache of up to 256 glyphs, and there can be as many scaled fonts
in use as the application needs and references (we maintain a holdover
cache of 512 scaled fonts as well).
Alternatively, as in this patch, we can maintain a global pool of glyphs
split between all open fonts. This allows a heavily used individual font
to cache more glyphs than we could allow if we used per-font glyph caches,
but at the same time maintains fairness across all fonts (by using random
replacement) and provides a cap on the maximum number of global glyphs.
The glyphs are allocated in pages, which are cached in the global pool.
Using pages means we can exploit spatial locality within the font
(nearby indices are typically used in clusters) to reduce frequency of small
allocations and allow the scaled font to reserve a single MRU page of
glyphs. This caching dramatically reduces the cairo overhead during the
cairo-perf benchmarks, and drastically reduces the number of allocations
made by the application (for example browsing multi-lingual site with
firefox).
A new meta-surface backend for serialising drawing operations to a
CairoScript file. The principal use (as currently envisaged) is to provide
a round-trip testing mechanism for CairoScript - i.e. we can generate
script files for every test in the suite and check that we can replay them
with perfect fidelity. (Obviously this does not provide complete coverage
of CairoScript's syntax, but should give reasonable coverage over the
operators.)
Use the return value to return the result from _cairo_hash_table_lookup()
(as opposed to filling an output parameter on the stack) as this (a)
results in cleaner code (no strict-alias breaking pointer casts), (b)
produces a smaller binary and (c) is measurably faster.
The wrapping of GCC attributes (such as cairo_private) needs to be
visible to any header file, including those that avoid cairoint.h such
as cairo-boilerplate. To achieve this we move the pre-processor magic to
its own header file and include it as required.
These were recently added, (as part of sparse integration?), but they
break boilerplate which reaches into at least cairo-types-private.h
and cairo-scaled-font-private.h. But boilerplate cannot see cairoint.h
or else it gets the internal sybol renaming, (with the INT_ prefix),
and then all the test suite tests refuse to link.
If this change reverts some recently-added functionality, (or
cleanliness), then we'll just need to find some other way to add that
back again without the breakage.
_cairo_cache_preserve -> _cairo_cache_freeze _cairo_cache_release -> _cairo_cache_thaw
Track rename of _cairo_cache_freeze/thaw.
Track rename. Add stacking behavior to _cairo_cache_freeze/thaw. Abstract out shrinking from _cairo_cache_insert so that _cairo_cache_thaw will also shrink as necessary.
Make this function static since its current limitation to accept an entry rather than a key makes it not as externally useful as would be desirable. Document this limitation.
Replace cairo cache implementation (this code from cworth)
No more global glyph cache to clean up
Store glyphs in new per-scaled font caches which hold user-space metrics and device space bounding boxes
Refactor glyph drawing APIs so that the surface API is invoked directly from the gstate code.
Add path creation/destruction routines (to hold glyph paths)
New implementation of scaled fonts which uses per-scaled_font caches for glyphs and keeps user-space metrics, device-space bboxes along with glyph images and/or glyph paths.
Adapt to new scaled font API changes.
New cache and scaled_font APIs
Repond to bug fix in metrics computation for glyphs where y values were rounded up instead of down because of a sign difference between cairo and FreeType.
Reviewed by: otaylor, cworth
