Add a custom fontconfig setup and ship Cantarell as part of it.
This should hopefully make it so that the tests always see the
same default font, as long as you have FONTCONFIG_FILE set up
correctly.
Update all affected tests.
The glyph in this test has extents that will be made smaller
by hinting, which poses some challenge for our renderers.
The scaled glyph rendering is too big for the 'small texture'
text setup, so we allow the test to fail there.
Tests the fix in the previous commit 93715b963e.
Sadly, the flipped variant of this test fails with the cairo
renderer, so it is marked as -nocairo. All the other renderers
pass it.
Instead of setting FONTCONFIG_FILE to a custom font configuration,
pass the directory containing the fonts as TEST_FONTS and use
FcConfigAppFontAddDir to add them to the default font configuration.
This tests the fixes in aa82190da659b5 and dcaa2c4ccb182c74cb40.
The test uses a custom font named 'text-mixed-color' which contains
six glyphs that are just boxes. Glyphs 1, 2, 3 are just plain glyphs,
and glyphs 4, 5, 6 are color glyphs in red, green and blue.
The glyphs are mapped to the characters A, B, C, D, E, F.
The test is currently disabled for cairo, since it has some issues
with transformed color glyphs.
The commit adds a custom fontconfig configuration in
testsuite/gsk/fonts/fonts.conf and sets the FONTCONFIG_FILE
environment variable for the gsk compare tests to point at it.
To use a custom font in tests, just drop it into the
testsuite/gsk/fonts/ directory.
The font configuration includes the system configuration,
so existing tests should not be affected.
