With the --repeat version of this test, Cairo needs to draw partially
clipped glyphs. However, there's a bug in Cairo where it doesn't account
for the subpixel positioning when clipping, so the glyphs get cut off at
the edge.
This is filed as https://gitlab.freedesktop.org/cairo/cairo/-/issues/821
Draw a grid of 21x21 box glyphs.
Each glyph is offset by n/20 pixels in the x and y direction.
The background color is carefully selected to be divisible by 16, so
that when the box glyph is subpixel positioned by 1/4th of a pixel
offset from the pixel grid in either direction, the result will be an
edge pixel whose color value can be computed exactly.
Cairo still rounds this wrong for color values >= 128 which is why we
use a dark gray that guarantees the resulting color values are all <128.
Add GSK_GPU_SKIP=glyph-align to turn off the glyph aligning.
FIXME: Should this be handled by the renderer at all or should we rely
on higher rendering layers to align glyphs properly?
This is kind of a tricky question just like with texture-scale nodes and
NEAREST filtering, because rendernodes can be embedded in other nodes
that disturb the pixel grid.
Transparency we need to support rounded corners. Client-side
shadows we need on platforms where the window manager does not
do them (mainly Wayland and X11). On platforms that support shadows
by default (macOS, Windows), we can just use them.
Clip from 1025px (which is what this test is about) to 1024px because the
GLES2 renderer in CI otherwise scales its repeat node offscreen for the
--repeat version of this test and that conveniently produces off-by-one
misrenderings everywhere.
However, we need to keep the image large enough so that all the glyphs
are actually rendered and not skipped which would not overflow the
cache.
This test is specifically engineered to trigger an overflow in the glyph
renderer that was theorized on IRC with an earlier patchset.
If only one slice was available, and that slice was not high enough to
hold the glyph we were trying to put in there, it would allocate a slice
that was too small. The check for the size was missing.
So now add a test that fills up all the slices in the glyph cache apart
from one and than tries to add one final glyph that is too large for the
last slice.
Previously, we only checked if the cache had exhausted the maximum
number of slices.
But we also need to check that the height of the slices doesn't exceed
the height of the texture.
After the node-editor crashed on me once too often, I decided to take a
good hard look at the parsing code and add a bunch of weird corner
cases into the testsuite.
That meant redoing the parser so that the error paths cause neither
crashes nor duplicated or wrong error messages.
This function wasn't needed so far so I didn't add it.
The next commits will use it.
I made has_url() return TRUE for the BAD_URL token, even though a
BAD_URL is not a valid URL. But parsing code will almost always want to
treat these tokesn the same way it would treat otherwise bad urls, so
returning TRUE here makes it go own the right error path in calling
code.
The gl renderer has an optimization where it uses the glyph atlas
to render color nodes that show up in the middle of text (e.g. for
underlines and carets). This adds a simple test for that scenario,
which hits this codepath.
