Previously, when inserting multiple lines of input at once, the underlying
Go data array was incorrectly shared in memory across multiple rows
of the textarea. This was causing input corruption, where a user trying
to modify one line would see their text added on the next line as well.
This patch fixes it.
There are many "interesting" cases:
- logical content is wider than display width (long lines).
In this case, we truncate.
- logical content is smaller than display height (fewer lines
than visible).
In this case, we pad with empty lines up to the specified height.
- logical content is higher than display height (more lines than
visible).
In this case, we truncate.
- style specifies a width wider than the display width.
In this case, we ignore the style width and
fit in the display width.
- style specifies a height higher than the display height.
Same as width, we ignore the style and fit in the display height.
- style specifies a narrower width or smaller height than the display.
In this case we obey the style.
