All signs so far seem to be that CPU is cheap for this application, but
memory is expensive. It's easy to get sluggish if the GC comes on.
After some experiments using https://github.com/yaukeywang/LuaMemorySnapshotDump,
one source of memory leaks is rendered fragments (https://love2d.org/wiki/Text
objects). I need to render text in approximately word-sized fragments to
mostly break lines more intelligently at word boundaries.
I've attached the files I used for my experiments (suffixed with a '.')
There's definitely still a leak in fragments. The longer I edit, the
more memory goes to them.
I've tried to keep the time period of the blinking similar to my
terminal.
Honestly I'm no longer sure if any of my experiments are showing a
statistically significant result. Let's see how it feels over a period
of time.
I'm testing this by moving the cursor around with my eyes closed, then
starting a stopwatch as I open my eyes. This seems to help a bit. I'm
able to acquire the cursor in 2s. At least the 10s outliers I used to
have with the circle or thin line don't seem to be happening.
I'm being unprincipled at the moment between pos and x,y coordinates.
Whatever is more convenient. Perhaps a cleaner approach will come to me
over time.
I almost pushed this to production. That would have been catastrophic;
the very first keystroke anyone typed into the editor would have failed.
And in the process, this fixes the next bug on my TODO list! Paste on
first line wasn't working. Now it is.
When long wrapping lines go past the current page, I find myself
scrolling before I get to the bottom. So let's scroll less, usually from
the start of the bottom-most line, even if it wraps multiple screen
lines.
The challenge with this is to ensure that a long line that fills the
whole page by itself doesn't get you stuck. I take some care to make
sure <pagedown> always makes forward progress.
Mouse stuff is pretty strenuous. For the first time I have to be careful
not to recompute too often. And I ran into a race condition for the
first time where resetting line.y within App.draw meant mouse clicks
were extremely unlikely to see line.y set.
Incredibly inefficient, but I don't yet know how to efficiently encode
undo mutations that can span multiple lines.
There seems to be one bug related to creating new drawings; they're not
spawning events and undoing past drawing creation has some weird
artifacts. Redo seems to consistently work, though.
I've written a few tests for delete_selection, but the way different
operations initialize the selection seems fairly standard and not worth
testing so far.