egui/text_selection/
accesskit_text.rs

1use emath::TSTransform;
2
3use crate::{Context, Galley, Id};
4
5use super::{CCursorRange, text_cursor_state::is_word_char};
6
7/// Update accesskit with the current text state.
8pub fn update_accesskit_for_text_widget(
9    ctx: &Context,
10    widget_id: Id,
11    cursor_range: Option<CCursorRange>,
12    role: accesskit::Role,
13    global_from_galley: TSTransform,
14    galley: &Galley,
15) {
16    let parent_id = ctx.accesskit_node_builder(widget_id, |builder| {
17        let parent_id = widget_id;
18
19        if let Some(cursor_range) = &cursor_range {
20            let anchor = galley.layout_from_cursor(cursor_range.secondary);
21            let focus = galley.layout_from_cursor(cursor_range.primary);
22            builder.set_text_selection(accesskit::TextSelection {
23                anchor: accesskit::TextPosition {
24                    node: parent_id.with(anchor.row).accesskit_id(),
25                    character_index: anchor.column,
26                },
27                focus: accesskit::TextPosition {
28                    node: parent_id.with(focus.row).accesskit_id(),
29                    character_index: focus.column,
30                },
31            });
32        }
33
34        builder.set_role(role);
35
36        parent_id
37    });
38
39    let Some(parent_id) = parent_id else {
40        return;
41    };
42
43    for (row_index, row) in galley.rows.iter().enumerate() {
44        let row_id = parent_id.with(row_index);
45        #[cfg(feature = "accesskit")]
46        ctx.register_accesskit_parent(row_id, parent_id);
47        ctx.accesskit_node_builder(row_id, |builder| {
48            builder.set_role(accesskit::Role::TextRun);
49            let rect = global_from_galley * row.rect_without_leading_space();
50            builder.set_bounds(accesskit::Rect {
51                x0: rect.min.x.into(),
52                y0: rect.min.y.into(),
53                x1: rect.max.x.into(),
54                y1: rect.max.y.into(),
55            });
56            builder.set_text_direction(accesskit::TextDirection::LeftToRight);
57            // TODO(mwcampbell): Set more node fields for the row
58            // once AccessKit adapters expose text formatting info.
59
60            let glyph_count = row.glyphs.len();
61            let mut value = String::new();
62            value.reserve(glyph_count);
63            let mut character_lengths = Vec::<u8>::with_capacity(glyph_count);
64            let mut character_positions = Vec::<f32>::with_capacity(glyph_count);
65            let mut character_widths = Vec::<f32>::with_capacity(glyph_count);
66            let mut word_lengths = Vec::<u8>::new();
67            let mut was_at_word_end = false;
68            let mut last_word_start = 0usize;
69
70            for glyph in &row.glyphs {
71                let is_word_char = is_word_char(glyph.chr);
72                if is_word_char && was_at_word_end {
73                    word_lengths.push((character_lengths.len() - last_word_start) as _);
74                    last_word_start = character_lengths.len();
75                }
76                was_at_word_end = !is_word_char;
77                let old_len = value.len();
78                value.push(glyph.chr);
79                character_lengths.push((value.len() - old_len) as _);
80                character_positions.push(glyph.pos.x - row.pos.x);
81                character_widths.push(glyph.advance_width);
82            }
83
84            if row.ends_with_newline {
85                value.push('\n');
86                character_lengths.push(1);
87                character_positions.push(row.size.x);
88                character_widths.push(0.0);
89            }
90            word_lengths.push((character_lengths.len() - last_word_start) as _);
91
92            builder.set_value(value);
93            builder.set_character_lengths(character_lengths);
94            builder.set_character_positions(character_positions);
95            builder.set_character_widths(character_widths);
96            builder.set_word_lengths(word_lengths);
97        });
98    }
99}
egui/text_selection/accesskit_text.rs

egui/text_selection/
accesskit_text.rs
