such that removing config.cache is not needed as frequently as it
is currently. We just detect and stale the cache results for our
own backends. If the user installs missing libraries, they still
need to remove the cache manually.
Note that everytime a change is made to configure.in and may change
the results of at least one CAIRO_BACKEND_ENABLE call, the
cairo_cache_version number should be increased.
if we don't want it. This stuff is tricky, but I hope to explain: In your
fontconfig configuration, you may match on "font", or on "pattern". Turning
subpixel on typically looks like:
<match target="font">
<test qual="all" name="rgba">
<const>unknown</const>
</test>
<edit name="rgba" mode="assign"><const>rgb</const></edit>
</match>
This works good enough, and if you set to ANTIALIAS_GRAY, this will not
override that. Now one may forget to match on "font" target, or intentionally
match on the pattern. That happens before cairo font options are substituted
in the pattern. So, to give a hint of subpixel in your config file, you can
write:
<match target="pattern">
<edit name="rgba" mode="assign"><const>rgb</const></edit>
</match>
You don't really need to check for current values, as FcConfigSubstitute is
run before merging cairo_font_options_t in. What this patch does, is to reset
pattern's rgba property if the font options explicitly ask for ANTIALIAS_GRAY.
This is the only place in cairo-ft-font.c that we use FcPatternDel, so I
thought some explanation is needed.
otherwise, it looks like "I don't care" and fontconfig configuration is
allowed to decide to turn subpixel on. This fixes the bug that subpixel
colors where showing up in fallback images in PS/PDF/SVG backends, observed
in the test fallback-resolution.
This only affects the image fallback in those backends, and avoids getting
colored pixels there if user's fontconfig configuration turns subpixel on.
This doesn't quite fix that problem though, more changes are needed/coming.
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.
