I introduced some compiler warnings into read_png() with the superfluous
introduction of a couple of volatile qualifiers. I'm sure at the time,
the reason was that gcc suggested adding them - however, ATM gcc issues
no warnings without them.
The CID font subsetting exposed a bug where the subset_glyph->is_scaled
return argument of _cairo_scaled_font_subsets_map_glyph() is sometimes
not assigned a value.
Make cairo-scaled-font-subsets.c limit Type1 font subsets to
256 glyphs. This allows Type1 subsetting to be enabled again
with type1-fallback as the fallback option for Type1 fonts.
Switching to CID font embedding requires a fallback font for
the case where CFF CID or TrueType CID subsetting fails.
The new function _cairo_type2_charstrings_init() added to
cairo-type1-fallback.c creates Type2 charstrings from glyph
paths. _cairo_cff_fallback_init() in cairo-cff-subset.c
wraps these charstrings in a CFF CID font.
OpenType/CFF fonts come in two types: CID and non CID.
CFF CID font subsetting was previously disabled in cairo
due 1) to the need to embed CFF CID fonts in PDF as a CID fonts
and 2) there is no easy way to convert CFF CID to CFF non CID.
With the switch to CID fonts cairo-cff-subset.c has been
updated to subset CID fonts and to covert non CID fonts to
CID. A further advantage of converting non CID CFF fonts
to CID is the reduction in size due to not embedding the
name of each glyph in the font subset.
cairo-scaled-font-subsets.c now provides three functions for creating subsets:
_cairo_scaled_font_subsets_create_scaled()
Create a subset for each scaled font with maximum size INT_MAX.
_cairo_scaled_font_subsets_create_simple()
Create subsets suitable for embedding as simple fonts in PS/PDF.
_cairo_scaled_font_subsets_create_composite()
Create subsets suitable for embedding as composite fonts in PS/PDF.
The _create_simple() and _create_composite() functions both merge
scaled fonts with the same face and an outline path available into
the same subset. _create_composite() has a maximum subset size of
65536 for outline fonts. Bitmap fonts have a separate subset for
each scale with a maximum subset size of 256.
The _create_simple() and _create_composite() functions both reserve
the first glyph in the subset for the .notdef glyph. CID fonts require
CID 0 to be .notdef.
Update Type1, TrueType and CFF subsetting to expect glyph 0 of each
subset to be the .notdef.
During MT cairo testing we get the error "libpng: Read Error" which is
emitted should the fread return fewer bytes than asked. However, this is
not necessarily an error, so double-check the ferror() status before
raising a png_error().
Toolkits like GTK+ almost always set a simple rectangular clip mask before
any cairo operation, so avoid the allocation for this simple case by
embedding a small number of XRectangles into the surface structure.
_cairo_surface_create_similar_solid() creates a fresh pattern to wrap
color, however sometimes the caller already has that pattern available.
In those circumstances we can pass the pattern as well as the color and
avoid the extra allocation.
For opaque surfaces the backends may use simpler code paths - for
example, the xlib backend may be able to use the Core protocol rather
than Render. So we only generate a surface with an alpha component if
the color is not opaque.
The so-attributed-to-X-server bug was that cairo maps the drawing
region to the pattern space, rounds the box, and uploads only that
part of the source surface to the X server. Well, this only works for
NEAREST filter as any more sophisticated filter needs to sneak a peek
at the neighboring pixels around the edges too.
The right fix involves taking into account the filter used, and the
pattern matrix, but for most cases, a single pixel should be enough.
Not sure about scaling down...
Anyway, this is just a workaround to get 1.4.4 out of the door. I'll
commit a proper fix soon.
