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.
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).
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".
Use our own escape sequence for the 'flash' terminfo entry.
Implemented by arming a timer FD and setting a boolean that indicates
we're currently "flashing".
The renderer draws a semi-transparent yellowish layer over the entire
window when "flashing" is active.
22;0|1|2t pushes the current window title/icon to the stack, while 23
pops it.
The second parameter, 0|1|2 has the following meaning:
0 - push/pop icon+title
1 - push/pop icon
2 - push/pop title
To avoid having to re-generate glyphs, cache the glyphs.
For now, we only cache ASCII characters, as this allows us to lookup
the cache by simply indexing with the character (into a 256-entry
array).
* Start selection on mouse button down
* Update selection on motion
* Button release cancels selection if there were no motion after start
* Renderer detects cells inside the selection and inverts their colors
The row array may now contain NULL pointers. This means the
corresponding row hasn't yet been allocated and initialized.
On a resize, we explicitly allocate the visible rows.
Uninitialized rows are then allocated the first time they are
referenced.
linefeed moves cursor down one row (columns stays the same), or, if
the cursor is at the last row, scrolls up one row.
reverse_index does the opposite; it moves the cursor *up* one row, or,
if the cursor is at the top row, scrolls *down* one row.
