When we've exhausted our own fallback list, try the font list provided
by fontconfig.
This means, the user's fallback fonts have priority, but in case all
of them fail, we hopefully get lucky with fontconfig...
And handle read() returning EAGAIN.
This fixes an issue with the keyboard repeat timer, which sometimes
would return EAGAIN.
Most likely because POLLIN was set on it, but then before we get to
handle it, the timer was canceled (by a key up event).
If we scroll enough, we'll eventually end up wrapping around the
entire scrollback buffer. At this point, a selection is no longer
valid, so cancel it.
Note: this was very obvious when scrolling in the alt screen, since
its scrollback buffer is what you see on the screen (i.e. it has no
scrollback).
Instead of running a repeater thread that writes the key to repeat
over a pipe, use a simple timer fd.
No more locking or condition signalling. No need to track
start/stop/exist states.
We simply set up the initial timeout value to be the 'delay', and the
interval to be the repeat 'rate'.
When scrolling through the scrollback lines, use scroll damage instead
of re-rendering the entire screen whenever it makes sense. I.e. when
the number of lines isn't a whole page or more.
When responding to a OSC 52 clipboard request, we need to base64
encode the clipboard data.
This is done in, potentially, several calls. Since we need at least 3
bytes to be able to produce any base64 output, we may have to buffer
up to 2 bytes between the callback calls with clipboard data.
This was being done incorrectly, where both bytes were written to
index 0 in the buffer.
The 'attributes' struct is now 8 bytes and naturally packed (used to
be 9 bytes, artificially packed).
'cell' struct is now 12 bytes, naturally packed (used to be 13 bytes,
artificially packed).
Furthermore, the glyph is stored as a wchar instead of a char*. This
makes it easier (faster) to do glyph lookup when rendering.
Fonts are now loaded with FT_LOAD_COLOR and we recognize and support
the FT_PIXEL_MODE_BGRA pixel mode.
This is mapped to a CAIRO_FORMAT_ARGB32 surface, that is blitted
as-is (instead of used as a mask like we do for gray and mono glyphs).
Furthermore, since many emojis are double-width, we add initial
support for double-width glyphs.
These are assumed to always be utf8. When PRINT:ing an utf8 character,
we check its width, and add empty "spacer" cells after the cell with
the multi-column glyph.
When rendering, we render the columns in each row backwards. This
ensures the spacer cells get cleared *before* we render the glyph (so
that we don't end up erasing part of the glyph).
Finally, emoji fonts are usually bitmap fonts with *large*
glyphs. These aren't automatically scaled down. I.e. even if we
request a glyph of 13 pixels, we might end up getting a 100px glyph.
To handle this, fontconfig must be configured to scale bitmap
fonts. When it is, we can look at the 'scalable' and 'pixelsizefixup'
properties, and use these to scale the rendered glyph.
