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Add cursor affinity

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This commit is contained in:
Audrey Dutcher 2023-01-10 20:12:12 -07:00 • committed by Jeremy Soller
parent e00109d77f
commit da842ec10d
2 changed files with 66 additions and 33 deletions
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81
src/buffer.rs
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@ -19,12 +19,24 @@ pub struct Cursor {
pub line: usize,
/// First-byte-index of glyph at cursor (will insert behind this glyph)
pub index: usize,
/// Whether to associate the cursor with the run before it (false) or the run after it (true)
/// if placed at the boundary between two runs
pub affinity: bool,
}
impl Cursor {
/// Create a new cursor
pub const fn new(line: usize, index: usize) -> Self {
Self { line, index }
Self::new_affinity(line, index, false)
}
/// Create a new cursor, specifying the affinity
pub const fn new_affinity(line: usize, index: usize, affinity: bool) -> Self {
Self {
line,
index,
affinity,
}
}
}
@ -61,7 +73,7 @@ pub struct LayoutRun<'a> {
}
impl<'a> LayoutRun<'a> {
/// Return the pixel span Some((x_start, x_width)) of the highlighted area between cursor_start
/// Return the pixel span Some((x_left, x_width)) of the highlighted area between cursor_start
/// and cursor_end within this run, or None if the cursor range does not intersect this run.
/// This may return widths of zero if cursor_start == cursor_end, if the run is empty, or if the
/// region's left start boundary is the same as the cursor's end boundary or vice versa.
@ -71,28 +83,20 @@ impl<'a> LayoutRun<'a> {
let rtl_factor = if self.rtl { 1. } else { 0. };
let ltr_factor = 1. - rtl_factor;
for glyph in self.glyphs.iter() {
let cursor = Cursor::new(self.line_i, glyph.start);
let cursor = self.cursor_from_glyph_left(glyph);
if cursor >= cursor_start && cursor <= cursor_end {
if x_start.is_none() {
x_start = Some(glyph.x + glyph.w * rtl_factor);
}
x_end = Some(glyph.x + glyph.w * rtl_factor);
}
}
let cursor = Cursor::new(self.line_i, self.glyphs.last().map_or(0, |glyph| glyph.end));
if cursor >= cursor_start && cursor <= cursor_end {
if x_start.is_none() {
x_start = Some(
self.glyphs
.last()
.map_or(0., |glyph| glyph.x + glyph.w * ltr_factor),
);
let cursor = self.cursor_from_glyph_right(glyph);
if cursor >= cursor_start && cursor <= cursor_end {
if x_start.is_none() {
x_start = Some(glyph.x + glyph.w * ltr_factor);
}
x_end = Some(glyph.x + glyph.w * ltr_factor);
}
x_end = Some(
self.glyphs
.last()
.map_or(0., |glyph| glyph.x + glyph.w * ltr_factor),
);
}
if let Some(x_start) = x_start {
let x_end = x_end.expect("end of cursor not found");
@ -106,6 +110,22 @@ impl<'a> LayoutRun<'a> {
None
}
}
fn cursor_from_glyph_left(&self, glyph: &LayoutGlyph) -> Cursor {
if self.rtl {
Cursor::new_affinity(self.line_i, glyph.end, false)
} else {
Cursor::new_affinity(self.line_i, glyph.start, true)
}
}
fn cursor_from_glyph_right(&self, glyph: &LayoutGlyph) -> Cursor {
if self.rtl {
Cursor::new_affinity(self.line_i, glyph.start, true)
} else {
Cursor::new_affinity(self.line_i, glyph.end, false)
}
}
}
/// An iterator of visible text lines, see [`LayoutRun`]
@ -378,18 +398,18 @@ impl<'a> Buffer<'a> {
let layout = line.layout_opt().as_ref().expect("layout not found");
for (layout_i, layout_line) in layout.iter().enumerate() {
for (glyph_i, glyph) in layout_line.glyphs.iter().enumerate() {
if cursor.index == glyph.start {
let cursor_end = Cursor::new_affinity(cursor.line, glyph.end, false);
let cursor_start = Cursor::new_affinity(cursor.line, glyph.start, true);
let (cursor_left, cursor_right) = if glyph.level.is_ltr() {
(cursor_start, cursor_end)
} else {
(cursor_end, cursor_start)
};
if *cursor == cursor_left {
return LayoutCursor::new(cursor.line, layout_i, glyph_i);
}
}
match layout_line.glyphs.last() {
Some(glyph) => {
if cursor.index == glyph.end {
return LayoutCursor::new(cursor.line, layout_i, layout_line.glyphs.len());
}
}
None => {
return LayoutCursor::new(cursor.line, layout_i, 0);
if *cursor == cursor_right {
return LayoutCursor::new(cursor.line, layout_i, glyph_i + 1);
}
}
}
@ -537,6 +557,7 @@ impl<'a> Buffer<'a> {
} else if y >= line_y - font_size && y < line_y - font_size + line_height {
let mut new_cursor_glyph = run.glyphs.len();
let mut new_cursor_char = 0;
let mut new_cursor_affinity = true;
let mut first_glyph = true;
@ -563,6 +584,7 @@ impl<'a> Buffer<'a> {
if right_half != glyph.level.is_rtl() {
// If clicking on last half of glyph, move cursor past glyph
new_cursor_char += egc.len();
new_cursor_affinity = false;
}
break 'hit;
}
@ -573,6 +595,7 @@ impl<'a> Buffer<'a> {
if right_half != glyph.level.is_rtl() {
// If clicking on last half of glyph, move cursor past glyph
new_cursor_char = cluster.len();
new_cursor_affinity = false;
}
break 'hit;
}
@ -584,11 +607,13 @@ impl<'a> Buffer<'a> {
Some(glyph) => {
// Position at glyph
new_cursor.index = glyph.start + new_cursor_char;
new_cursor.affinity = new_cursor_affinity;
}
None => {
if let Some(glyph) = run.glyphs.last() {
// Position at end of line
new_cursor.index = glyph.end;
new_cursor.affinity = false;
}
}
}
@ -599,7 +624,7 @@ impl<'a> Buffer<'a> {
} else if runs.peek().is_none() && y > run.line_y {
let mut new_cursor = Cursor::new(run.line_i, 0);
if let Some(glyph) = run.glyphs.last() {
new_cursor.index = glyph.end;
new_cursor = run.cursor_from_glyph_right(glyph);
}
new_cursor_opt = Some(new_cursor);
}