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widgets(textinput): fix cursor positioning

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Fix cursor positioning when jumping more than one cursor location at a
time, for example when pressing "ctrl+a" or "ctrl+e" to go to beginning
and end of the line
This commit is contained in:
Tim Culverhouse 2024-04-04 20:14:40 -05:00
parent 770f6d1c07
commit 310bff369b
1 changed files with 38 additions and 6 deletions
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44
src/widgets/TextInput.zig
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@ -98,13 +98,45 @@ pub fn sliceToCursor(self: *TextInput, buf: []u8) []const u8 {
return buf[0..offset]; return buf[0..offset];
} }
/// calculates the display width from the draw_offset to the cursor
fn widthToCursor(self: *TextInput, win: Window) usize {
var width: usize = 0;
var first_iter = GraphemeIterator.init(self.buf.items);
var i: usize = 0;
while (first_iter.next()) |grapheme| {
defer i += 1;
if (i < self.draw_offset) {
continue;
}
if (i == self.cursor_idx) return width;
const g = grapheme.slice(self.buf.items);
width += win.gwidth(g);
}
const second_half = self.buf.secondHalf();
var second_iter = GraphemeIterator.init(second_half);
while (second_iter.next()) |grapheme| {
defer i += 1;
if (i < self.draw_offset) {
continue;
}
if (i == self.cursor_idx) return width;
const g = grapheme.slice(second_half);
width += win.gwidth(g);
}
return width;
}
pub fn draw(self: *TextInput, win: Window) void { pub fn draw(self: *TextInput, win: Window) void {
if (self.cursor_idx > self.prev_cursor_idx and if (self.cursor_idx < self.draw_offset) self.draw_offset = self.cursor_idx;
self.prev_cursor_col > (win.width -| self.scroll_offset)) while (true) {
self.draw_offset += 1; const width = self.widthToCursor(win);
if (self.cursor_idx < self.prev_cursor_idx and log.debug("WIDTH TO CURSOR {d}, win.width {d}", .{ width, win.width });
self.prev_cursor_col < self.scroll_offset) if (width >= win.width) {
self.draw_offset -|= 1; self.draw_offset +|= width - win.width + 1;
continue;
} else break;
}
self.prev_cursor_idx = self.cursor_idx; self.prev_cursor_idx = self.cursor_idx;
self.prev_cursor_col = 0; self.prev_cursor_col = 0;