* action() returns void - this gets rid of checks in vt_from_slave()
* split up ACTION_PRINT into ACTION_PRINT (ASCII) and ACTION_UTF8_PRINT
ACTION_PRINT is on the hot path, and we want it streamlined.
* Remove run-time checkout for unimplemented state transitions, as we
shouldn't have any of those left.
* Don't re-load current VT state on each iteration in vt_from_slave()
There may be more SGR sequences after the 256-color/24-bit
sequence. Thus, check that we have *enough* parameters to parse the
256-color/24-bit SGR. It doesn't have to be *exactly* the required
number of parameters though.
Fixes issues with sequences like: \e[38;2;1;48;2;1m
This means we don't have to explicitly set the foreground/background
to the grid's default colors whenever we reset/clear a cell, and we
can instead simply memset() the entire cell to 0.
This also means the renderer has to get the default color when
rendering a cell without a foreground/background color set.
Vim, for example, changes the scroll region every time you scroll a
single line. Thus, resetting the damage queue is slow.
This reworks the damage handling of scroll updates:
* Split damage queue into two: one for scroll operations and one for
update/erase operations.
* Don't separate update/erase operations inside/outside the scroll
region
* Store the current scroll region in the scroll damage operation. This
allows us to stack multiple scroll operations with different scroll
regions.
* When updating update/erase operations after a scroll operation,
split the update/erase operations if necessary (the current scroll
operation may have a scroll region different from before, thus
forcing us to split existing update/erase operations.
* The renderer no longer erases after a scroll. The scroll operation
also adds an erase operation. This also means that erase operation
are subject to adjustments by later scroll operations.
Returns the value of parameter #idx, if available, or the specified
default value.
If the specified parameter does exist, but is 0, the default value is
returned.
