There are two different escape sequences that can be used to set the
cursor blink state: ‘CSI ? 12 h/l’ and ‘CSI Ps SP q’.
Up until now, they both modified the same internal state in foot. This
meant you could enable a blinking cursor with e.g. ‘CSI ? 12 h’ and
then disable it with ‘CSI 2 SP q’.
Since the ‘CSI ? 12’ escapes are used in the civis/cnorm/cvvis
terminfo entries, applications often ended up disabling the blink
state on exit (typically be emitting ‘cnorm’), requiring users to
manually re-enable blinking.
By splitting the internal state into two separate states, we can
improve the situation.
The cursor will blink if at least one of the two have been enabled.
The setting in foot.ini sets the default state of the ‘CSI Ps SP q’
escape.
This means if the user has enabled blinking in the configuration, the
cursor will blink regardless of civis/cnorm/cvvis. Which probably is
what the user wants.
If the user has NOT enabled blinking, civis/cnorm/cvvis act as
intended: cvvis blink, civis and cnorm do not.
If an application overrides the cursor blink/style with ‘CSI Ps SP q’,
that will override the user’s setting in foot.ini. But most likely
that too is intended (for example, the user may have configured the
application to use a different cursor style). And, a well written
application will emit the ‘Se’ terminfo sequence on exit, which in
foot is defined to ‘CSI SP q’, which will reset both the style and
blink state to the user configured style/state.
Closes#218
Alt screen applications normally reflow/readjust themselves on a
window resize.
When we do it too, the result is graphical glitches/flashes since our
re-flowed text is rendered in one frame, and the application re-flowed
text soon thereafter.
We can’t avoid rendering some kind of re-flowed frame, since we don’t
know when, or even if, the application will update itself. To avoid
glitches, we need to render, as closely as possible, what the
application itself will render shortly.
This is actually pretty simple; we just need to copy the visible
content over from the old grid to the new grid. We don’t bother with
text re-flow, but simply truncate long lines.
To simplify things, we simply cancel any active selection (since often
times, it will be corrupted anyway when the application redraws
itself).
Since we’re not reflowing text, there’s no need to translate e.g. the
cursor position - we just keep the current position (but bounded to
the new dimensions).
Fun thing: ‘less’ gets corrupted if we don’t leave the cursor at
the (new) bottom row. To handle this, we check if the cursor (before
resize) is at the bottom row, and if so, we move it to the new bottom
row.
Closes#221
wl_output_release, the use of which was recently introduced, is not
available until wl_output interface version 3.
However, only wl_output version 2 was bound. This lead to protocol
errors when a display was disconnected, causing foot to terminate.
Instead, only use wl_output_release if wl_output version 3 is provided
and bound. Otherwise, just use wl_output_destroy.
Closes: https://codeberg.org/dnkl/foot/issues/219
We call term_arm_blink_timer() from render_cell(), which runs in
multiple threads.
This caused multiple blink timer FDs to be created and registered with
the FDM, later causing read failures after one of those FDs had been
closed again.
This rarely happened under normal circumstances, but was easy to
trigger when the whole screen was full of blinking text.
As a small optimization, we don’t bother taking the lock if the timer
FD already is valid.
This is safe, because:
1) If the timer FD isn’t valid, we take the lock and then call
term_arm_blink_timer(), which again checks if the FD is already
valid.
2) The blink timer FD cannot be closed while we’re rendering cells. It
is only disabled in the FDM callback, which cannot execute while
we’re rendering.
e813883367 added “missing” short command
line options to footclient.
Except they weren’t missing; they were intentionally missing short
options and only supported long options.
This commit makes the new/missing short options “official”, by adding
documentation, zsh completions and including them in usage().
fdm_ptmx(), the FDM callback handler for ptmx data, is just as much in
the hot path as vt_from_slave(). It is also slightly more complicated
than a read() followed by a call to vt_from_slave().
As a result, some benchmarks performed significantly worse in a
partial PGO build than in a full PGO build, since fdm_ptmx() wasn’t
PGO:d.
To be able to feed data through fdm_ptmx(), we need to set up the
delayed rendering timer FDs, configure the timeout values, and provide
a readable FD it can read the VT data from.
The latter is done with a memory FD. This ensures *all* VT data is
loaded into memory before we feed it to the parser.
