This adds a flag, -p,--presentation-timings, that enables input lag
measuring using the presentation time Wayland protocol.
When enabled, we store a timestamp when we *send* a key to the
slave. Then, when we commit a frame for rendering to the compositor,
we request presentation feedback. We also store a timestamp for when
the frame was committed.
The 'presented' callback then looks at the input and commit
timestamps, and compares it with the presented timestamp.
The delay is logged at INFO when the delay was less than one frame
interval, at WARN when it was one frame interval, and at ERR when it
was two or more frame intervals.
We also update statistic counters that we log when foot is shut down.
Instead of trying to figure out if we had to render
something (i.e. something in the grid was dirty), and using that to
determine whether to post a callback or not, we now let
render_refresh() set a flag indication we need to render another
frame.
This simplifies render_grid(), which now _always_ renders, and pushes
it to the compositor.
The callback handler checks the pending flag and simply doesn't call
render_grid() when there's no more pending state to render.
This ends up reducing the number of wakeups when e.g. having a
blinking cursor.
Blinking can be enabled either by setting the cursor style with
CSI Ps SP q
and selecting a blinking style.
Or, with 'CSI ? 12 h'
Note that both affect the same internal state. I.e. you can disable
blinking with CSI ? 12l after having selected a blinking cursor
style. This is consistent with XTerm behavior.
This shouldn't be necessary, but Sway acts up when the subsurface
exceeds the parent surface (window, in this case) size, and extends
the window size (if floating), leaving it with no content
There were two errors:
* We subtracted half the line width instead of adding it to the
baseline
* We rounded the line positioning and thickness before the positioning
calculation. In particular, rounding the thickness before using it
to adjust the position was wrong. Now we round just before the
pixman call.
This is what we used as baseline for regular glyphs anyway. Thus, we
can update that code to call font_baseline() now. This makes it easier
to change how we define the baseline in the future.
When the user had configured the cursor color, we failed to
invert (reverse) the foreground and background color when the cursor
was on a cell with the 'reverse' attribute set.
When doing "small" scrolls (typically done via mouse wheel or
similar), we render the scrolling by emitting a "scroll damage".
A recent commit changed how scroll damage is rendered; only when the
view is at the bottom ("following" the screen output) do we render the
damage.
To fix this, add a new type of scroll damage,
SCROLL_DAMAGE_IN_VIEW and SCROLL_DAMAGE_REVERSE_IN_VIEW.
These signal to the renderer that it should always render the damage.
Since we now initialize the worker threads from term_init(), which
returns before the threads terminate, we can no longer use
stack-allocated worker contexts.
We _could_ put them in the terminal struct. But a simpler solution is
to allocate them in term_init(), and let the threads free them when
they don't need them anymore.
When user has scrolled back in the output history, new output should
not trigger scrolling.
This was true for normal cell rendering, which renders the cells *in
view*, not caring where the "front" of the output is.
However, we still applied scroll damage. I.e. we memmoved part of the
screen.
The fix is simple; only apply scroll damage when the view is at the
front of the output.
We do however need access to it, so provide a pointer. The difference
is that now we can have a *single* wayland instance, but multiple
terminal instances.
Short term, we want to break out the wayland backend from the terminal
struct. Long term, we might want to support multiple windows.
One step towards both the above is separating global wayland objects
from per-window objects.
Not all compositors support buffer re-use. I.e. they will call the
frame callback *before* the previous buffer has been
released. Effectively causing us to swap between two buffers.
Previously, this made us enter an infinite re-render loop, since we
considered the window 'dirty' (and in need of re-draw) when the buffer
is different from last redraw.
Now, we detect the buffer swapping case; size must match, and we must
not have any other condition that require a full repaint.
In this case, we can memcpy() the old buffer to the new one, without
dirtying the entire grid. We then update only the dirty cells (and
scroll damage).
Note that there was a bug here, where we erased the old
cursor *before* checking for a new buffer. This worked when the buffer
had *not* changed.
Now that we need to handle the case where it *has* changed, we must do
the memcpy() *before* we erase the cursor, or the re-painted cell is
lost.
This makes foot work on Plasma, without burning CPU. The memcpy() does
incur a performance penalty, but we're still (much) faster than
e.g. konsole. In fact, we're still mostly on par with Alacritty.
This ensures we always have a valid (but possibly incorrect) scaling
value. This allows us to simplify code that uses the scale - it
doesn't have to verify the scale if valid.
Furthermore, since render_resize() is the function that actually
updates term->scale, make sure to call it *before* updating the
cursor (otherwise, the cursor will use the old scaling value).
Use the 'yellow' color from the 'regular' range of colors (SGR 33) for
background when we have a match, or 'red' from the 'regular' range of
colors (SGR 31) when we don't have a match.
Foreground uses the 'black' color from the regular range of
colors (SGR 30).
