This ensures we only perform a single update with the most up-to-date
information about line height, default character width, and specific
character widths. If this update causes more lines to be drawn we may
measure again, but not necessarily.
This prevents the double-update of the lines component when changing
the font-size, line-height and font-family. We detect the update of
these values in the root component and trigger a measurement. If the
measurement determines that the pixel values have changed, *then* we
update the lines.
Previously, SelectionsComponenet::shouldComponentUpdate was storing the
ranges for selections as a side effect. We also were passing boolean
values (cursorMoved and selectionUpdated) to determine if these
components should update.
Now, we compute a simple hash of screen ranges for selections and
cursors in the root component and pass them down. This simplifies
shouldComponentUpdate for selections and allows us to implement one
for cursors.
I don't think that this component was really carrying its weight. Its
render function basically passed through directly to other components
that updated between renders, but didn't contain any content on its
own that actually changed after the first render.
React components seem to carry overhead, so I want every component we
use to count. Also, I'm considering circumventing some of React's
standard update logic for performance reasons, and making the structure
more shallow will help with that.
The indentation level is not anymore reduced by adding a new line,
which previously caused multiple reductions of the indentation level.
This fixes the behavior of HTML closing tags, which currently
"jump" backwards if you try to move them down.
If a mousewheel event is triggered when the editor can't be scrolled,
we still want to clear the mouseWheelScreenRow. This is typically done
when we stop scrolling, but if we never start scrolling it will never
happen. This commit adds another timeout to cover that case.
