A top-level font now has a list of fallback fonts. When a glyph cannot
be found, we try each fallback font in turn, until we either find one
that has the glyph, or until we've exhausted the list.
To make this actually work in practise (read: to make performance
acceptable), the cache is re-worked and is now populated on demand.
It also supports non-ASCII characters, by using the 4-byte unicode
character as index instead.
Since having an array that can be indexed by a 4-byte value isn't
really viable, we now have a simple hash table instead of an array.
This patch takes a bit from the foreground color value in a
cell (todo: split up foreground/background into bitfields with a
separate field for 'foreground/background' has been set), and only
re-renders cells that aren't marked as clean.
Note: we use a 'clean' bit rather than a 'dirty' bit to make it easy
to erase cells - we can (keep doing) do that by simply memsetting a
cell range to 0.
Initial POC that uses freetype to render the glyphs. The bitmap
produced by freetype contains the alpha value.
We use this bitmap in a mask surface and then draw the final glyph
with cairo by applying the source rgb using the OVER operator and the
freetype generated alpha mask as surface mask.
Note that we only support grayscale antialiasing (and no
antialiasing).
We are probably not setting the antialias options correctly either.
The main problem is knowing:
* The correct *cell* (to be able to render the *content* when erasing
the old cursor)
* Whether the cursor has moved (to determine whether to stop the
rendering loop or not)
* Where on the *screen* the cursor is/was (since the terminal may be
partly scrolled back)
This patch stores three static variables:
* last_cursor is used to compare against current cursor to see if the
cursor has moved or not
* last_cursor_on_screen is the actual screen coordinates the cursor
was rendered at (typically the same as last_cursor, but may be
offset by the view)
* last_cursor_cell is a pointer to the cell to render
The default is to reverse the foreground/background colors in the cell
with the cursor.
But, if the user configures a specific set of cursor colors, those
will always be used, regardless of other cell attributes (dim, reverse
etc).
The cursor color is specified as two color values, 'text' and
'cursor'.
The block cursor uses the 'cursor' color as background, and the 'text'
color for the glyph.
All other cursor styles uses the 'cursor' color for the cursor, but
uses the cell's foreground color for the glyph (meaning,
dim/reverse/etc applies).
I.e. it issues a \E[2 q regardless of what we've configured the
terminfo Se entry to.
So, make \E[2 q mean "the user configured cursor style" (which
defaults to 'block').
According to the specs, \E[0 q means a blinking block cursor. However,
since it also states that \E[1 q *also* is a blinking block cursor,
and that it is the default, *and* given that fact that parameter-less
CSIs typically means "reset", let's make it mean "reset to the user
configured cursor style".
