Use g_newa() instead of VLAs, as VLAs may never be supported by some
compilers as it became optional in C11 and there are concerns about their
implementations in compilers that do support it.
https://bugzilla.gnome.org/show_bug.cgi?id=773299
Forces a full redraw every frame.
This is done generically, so it's supported on every renderer.
For widget-factory first page (with the spinner spinning and progressbar
pulsing), I get these numbers per frame:
action clipped full redraw
snapshot 0ms 7-10ms
cairo rendering 0ms 10-15ms
Vulkan rendering 3-5ms 18-20ms
Vulkan expected * 0ms 1-2ms
GL rendering unsupported 55-62ms
* expected means disabling rendering of unsupported render nodes,
instead of doing fallback drawing. So it overestimates the performance,
because borders and box-shadows are disabled.
It's faster to render once for every rectangle in the clip region than
rendering the outline of the clip region.
Especially because this reduces the time necessary to build up the frame
data.
In widget-factory (where we have 3 rectangles), this leads to a 5x
speedup in the rendering time rendering alone.
Snapshotting time goes from 10ms to ~1ms, which is another huge
improvement.
Note: We interpolate premultiplied colors as per the CSS spec. This i
different from Cairo, which interpolates unpremultiplied.
So in testcases with translucent gradients, it's actually Cairo that is
wrong.
Homogeneous branches repeated the calculation/assignment of the initial
space available to children. This avoids that by shuffling some code.
Perhaps more importantly, in doing that, I ended up with some ambiguous
names, and Company and I realised how vague the pre-existing naming was.
"size" becomes "extra_space", as this is what it represents. Conversely,
"extra" becomes "size_given_to_child" (albeit still given out in two
different ways depending on whether the Box is homogeneous). My hope is
that these sections of code are now somewhat less baffling than before!
This is now tracking the clips added by the clip nodes.
If any particular node can't deal with a clip, it falls back to Cairo
rendering. But if it can, it will render it directly.
Now that every call to GtkCellArea is a snapshot call and no more cairo
calls are left, move the actual differentiation between Cairo and
Snapshot down to the cell renderer.
Little tool that creates a bunch of test files to throw add the
rendernode binary.
They should really be part of a testsuite, but we have none, so OI just
put them here.
