Fixes#1159
The cursor position is an "active" coordinate (defined at the top of
Screen.zig), but our resize was treating it as a "viewport" coordinate.
Fixes#741
This completely reimplements double-click-and-drag logic for selecting
by word. The previous implementation was horribly broken. See #741 for
all the details.
The implemented logic now is:
* A double-click initiates a select-by-word selection mechanism.
- A double-click may start on a word or whitespace
- If the initial double-click is on a word, that word is immediately selected.
- If the initial double-click is on whitespace, the whitespace is not selected.
* A "word" is determined by a non-boundary character meeting a boundary character.
- A boundary character is `NUL` ` ` (space) `\t` `'` `"`
- This list is somewhat arbitrary to make the terminal "feel" good.
- Cell SGR states (fg/bg, bold, italic, etc.) have no effect on boundary determination or selection logic.
* As the user drags _on the same line_:
- No selection change occurs until the cursor is over a new word. Whitespace change does nothing.
- When selection is over a new word, that entire word added to the selection.
* When the user drags _up_ one or more lines:
- If the cursor is over whitespace, all lines from the selection point up to but not including the cursor line are selected.
* This selection is done in accordance to the previous rules.
- If the cursor is over a word, the word becomes the beginning of the selection.
- The end of the selection in all cases is the first word at or before the initial double-click point.
* When the user drags _down_ one or more lines:
- The same logic as _up_ but swap the "beginning" and "end" of selection terminology.
* With this logic, the behavior of Ghostty has the following invariants:
- Whitespace is never selected unless it is between two selected words
- Selection implies at least one word is highlighted
- The initial double-click point marks the beginning or end of a selection, never the middle.
This logic is truly terrible and I know for certain there is an easier
way to calculate this. I also know there are some bugs here. But, the
user-facing result is not bad so let's start with this.