Arcs were appealing, but they have a fatal flaw: we can't
split our arcs without changing the ellipse they trace.
That could be fixed by adding an extra parameter, but then
it is no longer any better than conics.
So switch back to conics, which have the advantage that they
are used elsewhere.
Add a new curve type for elliptical arcs
and use it for rounded rectangles and circles.
We use the 'E' command to represent elliptical
arcs in serialized paths.
FLT_EPSILON is the distance between 1.0 and the next distinct floating
point number, and doesn't necessarily have anything to do with the
precision we can expect from a series of floating-point calculations.
Experimentally, 1e-6 is achievable, even on platforms with unusual
floating point implementations like i387.
Resolves: https://gitlab.gnome.org/GNOME/gtk/-/issues/6051
Bug-Debian: https://bugs.debian.org/1050076
Signed-off-by: Simon McVittie <smcv@debian.org>
When redoing a history entry, its `is_modified` flag is not
reflected to the history state tracker. So GtkTextBuffers may
expose a modified=FALSE status, despite a change was actually
applied to the buffer.
For the undo case, an `is_modified_set` flag was set on the last
entry of the undo queue when a change of the modified state of
the history is requested. This commit does the same on the first
entry of the redo queue.
Closes#5777
The builder test was relying on default visiblity
for non-static functions. Make it explicit that we
want to export these functions, so the test keeps
working when we change the default visibility.
The relevant question here is about details, because we have to choose
if we declare alpha-only formats as having their (nonexistant) color
channels premultiplied or not, so that the code paths using them can do
the right thing.
Because we are premultiplied by default, it makes sense to treat alpha
like that, because then the alpha-only code doesn't need to do
workarounds for straight alpha.
Where this is relevant of course is when expanding the alpha channel
into color channels, where we want to end up with white.
So make sure we do color = alpha there instead of color = 1 like we did
before.
We need them for mask-only textures.
For tiffs, we convert the formats to RGBA (the idea that tiff can save
everything needs to be buried I guess) as tiffs can't do alpha-only.
Inverted alpha masks have an effect on the source, even if the mask
doesn't cover the source at all - or worse, is completely clipped out.
The GL renderer handles this fine, but Cairo and Vulkan had
optimizations that got this wrong.
In particular, fix the combination of luminance and alpha. We want to do
mask = luminance * alpha
and for inverted
mask = (1.0 - luminance) * alpha
so add a test that makes sure we do that and then fix the code and
existing tests to conform to it.
