Keep at least 1 second of frame timings.
This is necessary for 2 reasons - a real one and a fun one.
First, with the difference in monitor refresh rates, we can have 48Hz
latops as well as 240Hz high refresh rate monitors. That's a factor of
4, and tracking frame rates in both situations reliably is kind of hard
- either we track over too many frames and the fps take a lot of time to
adjust, or we track too little time and the fps fluctuate wildly.
Second, when benchmarking with GDK_DEBUG=no-vsync with a somewhat fast
renderer (*cough*Vulkan*cough*) frame rates can go into insane dimensions
and only very few frames are actually getting presentation times
reported. So to report accurate frame rates in those cases, we need a
*very* large history that can be 1000s of times larger than the usual
history. And that's just a waste for normal usage.
Previously, our reported fps numbers could be too low when the start
timings weren't complete. In that case we would use the frame time, but
the frame time is the time when the frame was rendered, which is quite a
few milliseconds before it is presented.
So in that case we would not report the difference in presentation
times, but the difference from start of rendering. However, those times
are way more variable and can smear over the whole frame because they
depend on when we received the frame callbacks to high priority GSources
as well as our own render time predictions.
This happened in particular with GDK_DEBUG=no-vsync and could report
number that are off by a factor of 2.
Now we skip any incomplete frames, because those frames never have
presentation times reported. This makes it theoretically more likely to
not being able to report fps at all, but I'd rather have no fps than fps
off by a factor of 2.
The fps used to get garbled when hitting >=10,000fps. That's quite
unlikely to happen for long periods, but it can happen for short bursts
(like after alt-tabbing).
So just handle more digits to make the display survive those corner cases.
Previously, we drew the same width no matter how many digits the fps
number had, which left a lot of empty space.
But we can use some quite simple math to avoid that by just shrinking
the background by the width of the non-rendered glyphs.
We don't really expect backends to make this settable, and
fractional scaling makes this more complicated anyway. The
scale values can be seen on the General tab, for the monitor,
and on the surface for each toplevel.
A small step towards respecting our own deprecations. While we
are at it, make the control only select the font family, since
that is the intention of the font setting. Font style and size
are under the control of the css, and we have a font scale slider
right below to influence font size globally.
Add a --colorflip option to the compare-render test. This applies
a color matrix to the node, which has the intended side-effect of
convincing the Vulkan renderer to use its uber shader, so we get
test results comparing the uber output to its non-uber siblings.
We were turning off hinting and subpixel positioning if the
transform isn't 2D affine. The idea behind this was that transforms
likely indicate animations, and for animations, this may reduce
jitter. But the heuristic of transform==animation is not very
reliable, and we pay for this with a jump from hinted to unhinted
at the beginning and end of it. Also, the heuristic does not even
work for the most relevant 'animation' we have today: scrolling.
So, lets drop this for now. We can revisit it later.
When getting the hinted version of fonts, they often come in sequentially.
This helps reduce overhead in many sequential gtk_text_node_new() on with
fractional scaling as you see from GtkSourceView.
Some maps are used for read only and do not require uploading contents
back to the GPU afterwards. In other cases, we can often upload less than
the fully allocated buffer size.
The documented icon flags didn't match the actual constants used by GTK when
reading and updating icon theme cache files. Fix the values of flags in the
documentation.
Closes: https://gitlab.gnome.org/GNOME/gtk/-/issues/6489
