If the value is specified without a unit, then the value is assumed to
be in points, subject to DPI scaling.
The value can optionally have a ‘px’ suffix, in which case the value
is treated as a raw pixel count.
When set, the grid contents is centered in the window. I.e. the
left/right and top/bottom margins are equal (+- 1px).
This causes the content to “jump” while doing an interactive resize,
but may still be preferred in e.g. a tiling WM.
Closes#273
When tweak.allow-overflowing-double-width-glyphs=yes, then certain
glyphs are allowed to overflow into the neighbouring cell.
However, if the cell “owning” the double-width glyph is erased (_only_
that cell), then the cell overflowed into is not redrawn, causing
part of the double-width glyph to remain on screen.
To avoid checking for these glyphs when printing to the terminal (i.e
at parse time), simply mark both cells as dirty when we render the
overflowing glyph.
Yes, this means that the cells will always be re-rendered. We count on
them only making up a small portion of the screen.
* ‘term’ struct contains an array of 160 fcft glyph pointers
* the glyph pointers are lazily allocated when we need to draw a box
drawings character
* Filtering out box drawings characters is easy - they are (except
unicode 13, which isn’t handled yet )all in a single range.
We use pre-multiplied alpha color channels, but were having bad
rounding errors due to the alpha divider being truncated to an
integer.
The algorithm for pre-multiplying a color channel is:
alpha_divider = 0xffff / alpha
pre_mult_color = color / alpha_divider
In order to fix the rounding errors, we could turn ‘alpha_divider’
into a double.
That however would introduce a performance penalty since now we’d need
to do floating point math for each cell.
The algorithm can be trivially converted to:
pre_mult_color = color * alpha / 0xffff
Since both color and alpa values are < 65536, the multiplication is
“safe”; it will not overflow an uint32_t.
Closes#249
When calculating the offset into the search string, from where to
start rendering, take into account that the cursor position is
in *characters*, and the glyph-offset is in *cells*.
While doing a scrollback search, the pre-edit string should be
rendered in the search box, not in the grid.
Note that we don’t yet support IME in scrollback search mode. This
patch simply prevents the pre-edit text being rendered in the grid,
in the “background”, while searching.
The position calculated by render_grid() may be -1,-1 if the cursor is
currently hidden.
This fixes a crash when trying to input IME while the cursor is
hidden.
This is done by allocating cells for the pre-edit text when receiving
the text-input::done() call, and populating them by converting the
utf-8 formatted pre-edit text to wchars.
We also convert the pre-edit cursor position to cell positions (it can
cover multiple cells).
When rendering, we simply render the pre-edit cells on-top off the
regular grid. While doing so, we also mark the underlying, “real”,
cells as dirty, to ensure they are re-rendered when the pre-edit text
is modified or removed.
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
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.
When checking if we should allow a single-width character double-width
glyph to overflow into the next cell, require the next cell to either
be empty, or contain a space.
Closes#203
Up until now, we’ve always re-rendered the entire image (the part of
it that is visible at least), *every* time we render a frame.
This is not really needed. In many cases, the cells covered by the
image hasn’t been touched.
Rewrite the sixel rendering code to only render the part of the sixel
image that covers dirty cells.
This is done on a per-row basis. I.e. Each *row* of the image that
covers at least one dirty cell is re-rendered. For this to work, we
now also dirty all cells covered by the image when we emit the image.
Finally, for this to work, the sixels need to be rendered *before* we
do the normal grid render pass (since that will clear all dirty bits).
On some platforms, TIOCSWINSZ has a very large value, >
0x80000000.
On some platforms, the `request` argument to `ioctl(3)` is an `int`.
For platforms where both of the above is true, gcc will warn (and
error out if compiled with `-Werror`) on:
ioctl(fd, TIOCSWINSZ, ...)
To silence this warning, we need to cast `TIOCSWINSZ` to an
integer.
However, doing this on platforms where `request` is an `unsigned long`
will result in `TIOCSWINSZ` being sign-extended (and thus we end up
with an invalid value).
It seems that casting to `unsigned int` works in both cases; it
silences the long -> int conversion warning, while also preserving the
correct value in all cases.
Bind to xdg-shell version 2 if available, as this enables us to
track our window’s ‘tiled’ state in the ‘configure’ events.
This in turn allows us to stash the ‘old’ window size when being
tiled, to be used again when restoring the window size when un-tiled.
Add anew config option, ‘bell=none|set-urgency’. When set to
‘set-urgency’, the margins will be painted in red (if the window did
not have keyboard focus).
This is intended as a cheap replacement for the ‘urgency’ hint, that
doesn’t (yet) exist on Wayland.
Closes#157
An odd cell width/height sometimes resulted in an odd grid
size. Combined with a scaling factor of e.g. 2, that led to a rounding
error when converting pixel sizes to logical window sizes.
As a result, the _next_ configure event would cause us to loose a
pixel, which led to us dropping a row from the grid.
The initial window size is set *before* we’re initially mapped. This
means we don’t (yet) know on which output we’ll be mapped. _That_
means we don’t know which scaling factor to use.
This implements a best effort attempt, where we use the “guessed”
scaling factor. This will always be correct in single-monitor
configurations, but may be wrong in multi-monitor setups with
different scaling factors.
