as it's not portable and lack of it could seriously break the truetype
subsetting code. Now, instead of using int32_t and int64_t, we use
multiple int16_t items, to avoid any alignments. Fortunately, we are
not using any of the fields involved, so no code changes necessary.
This approach to fixing the bug is valid since there is code in pixman
for rendering to BGR images, (which is why cairo 1.0 worked with BGR X
servers for example). But, since we don't want to advertise additional
image formats we implement this through a new cairo_internal_format_t.
This is rather fragile since we don't want to leak any internal formats
nor do we ever want an internal format to be used somewhere a real
format is expected, (and trigger a CAIRO_FORMAT_VALID assertion failure).
More comments than code are added here to help compensate for the
fragility and to give some guidance in fixing this mess in a better way
in the future.
In addition to helping us preserve a sharp line between which symbols are
part of the public API and which are private parts of the implementation,
this can also help mozilla avoid clashes between its modified, internal
copy of cairo and the system version of cairo. See the mozilla bug here:
https://bugzilla.mozilla.org/show_bug.cgi?id=341874
Add a load_truetype_table function to cairo_scaled_font_backend_t and
use it to load the truetype sfnt tables. Implement this with freetype
for the freetype font backend and use GetFontData for win32. Atsui
remains unimplemented, and still falls back to type3 fonts.
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
There appears to be a bug in some X servers which is triggered by
rendering 1-bit glyphs with zero size via the functions
XRenderAddGlyphs and XRenderCompositeText8 (and likely its variants).
We avoid this bug by making a copy of the glyphs array which does not
include any of the size-zero glyphs so that the X server never sees them.
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.
