agg-gui 0.4.0

Immediate-mode Rust GUI library with AGG rendering, Y-up layout, widgets, text, SVG, and native/WASM adapters
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215

//! Painting for [`RichTextEdit`], split out of `editor.rs`.
//!
//! Walks the cached [`DocLayout`] top-down and flips into the framework's Y-up
//! space (folding in padding + scroll via
//! [`doc_top_yup`](RichTextEdit::doc_top_yup)), mirroring the read-only
//! [`RichTextView`](super::super::view::RichTextView) painter but adding the
//! selection band, a focus border, and a blinking caret drawn in the overlay
//! pass (clipped to the inner band, `TextArea`-style).

use std::sync::Arc;

use crate::draw_ctx::DrawCtx;

use super::super::layout::LineLayout;
use super::RichTextEdit;

impl RichTextEdit {
    /// Paint background, selection, text runs, decorations, border and bar.
    pub(super) fn paint_content(&mut self, ctx: &mut dyn DrawCtx) {
        let v = ctx.visuals();
        let w = self.bounds.width;
        let h = self.bounds.height;
        let default_color = v.text_color;

        // Background.
        ctx.set_fill_color(v.widget_bg);
        ctx.begin_path();
        ctx.rounded_rect(0.0, 0.0, w, h, 4.0);
        ctx.fill();

        // Clip to the padded inner rect so scrolled content can't leak.
        ctx.clip_rect(
            self.padding,
            self.padding,
            (w - self.padding * 2.0).max(0.0),
            (h - self.padding * 2.0).max(0.0),
        );

        let Some(layout) = self.layout.clone() else {
            ctx.reset_clip();
            return;
        };
        let sel = self.core.borrow().selection();
        let (a, b) = sel.ordered();
        let sel_active = !sel.is_empty();
        let sel_color = if self.focused {
            v.selection_bg
        } else {
            v.selection_bg_unfocused
        };

        let mut y_top = 0.0f64;
        for (bi, block) in layout.blocks.iter().enumerate() {
            // List marker on the first line's baseline.
            if let (Some(marker), Some(font), Some(first)) =
                (&block.marker, &block.marker_font, block.lines.first())
            {
                let baseline_up = crate::font_settings::snap_baseline_y(
                    self.doc_top_yup() - (y_top + first.baseline_from_top),
                );
                let color = first
                    .fragments
                    .first()
                    .and_then(|f| f.style.text_color)
                    .unwrap_or(default_color);
                ctx.set_font(Arc::clone(font));
                ctx.set_font_size(block.marker_font_size);
                ctx.set_fill_color(color);
                ctx.fill_text(marker, self.padding + block.marker_x, baseline_up);
            }

            for line in &block.lines {
                let line_top = y_top;
                let baseline_up = crate::font_settings::snap_baseline_y(
                    self.doc_top_yup() - (line_top + line.baseline_from_top),
                );
                let line_bottom_up = self.doc_top_yup() - (line_top + line.height);
                let text_x0 = self.padding + block.text_left + line.align_dx;

                // Selection band behind the line.
                if sel_active && bi >= a.block && bi <= b.block {
                    let block_lo = if bi == a.block { a.byte } else { 0 };
                    let block_hi = if bi == b.block {
                        b.byte
                    } else {
                        line.end_byte.max(line.start_byte)
                    };
                    let lo = line.start_byte.max(block_lo);
                    let hi = line.end_byte.min(block_hi);
                    if hi >= lo {
                        let x0 = text_x0 + self.x_in_line(line, lo);
                        let x1 = text_x0 + self.x_in_line(line, hi);
                        let width = (x1 - x0).max(if bi < b.block { 4.0 } else { 0.0 });
                        if width > 0.0 {
                            ctx.set_fill_color(sel_color);
                            ctx.begin_path();
                            ctx.rect(x0, line_bottom_up, width, line.height);
                            ctx.fill();
                        }
                    }
                }

                self.paint_line(ctx, line, text_x0, baseline_up, default_color);
                y_top += line.height;
            }
        }

        ctx.reset_clip();

        // Focus border.
        let border = if self.focused {
            v.accent
        } else if self.hovered {
            v.widget_stroke_active
        } else {
            v.widget_stroke
        };
        let line_width = if self.focused { 2.0 } else { 1.0 };
        ctx.set_stroke_color(border);
        ctx.set_line_width(line_width);
        ctx.begin_path();
        let inset = line_width * 0.5;
        ctx.rounded_rect(
            inset,
            inset,
            (w - line_width).max(0.0),
            (h - line_width).max(0.0),
            4.0,
        );
        ctx.stroke();
        // Scrollbar paints in `paint_overlay` (after the cache blit) so its
        // animation doesn't force the styled-text bitmap to re-raster.
    }

    /// Paint the fragments of one line (text, highlight, underline/strike).
    fn paint_line(
        &self,
        ctx: &mut dyn DrawCtx,
        line: &LineLayout,
        text_x0: f64,
        baseline_up: f64,
        default_color: crate::color::Color,
    ) {
        let line_bottom_up = baseline_up + line.baseline_from_top - line.height;
        for frag in &line.fragments {
            let fx = text_x0 + frag.x;
            if let Some(hl) = frag.style.highlight {
                ctx.set_fill_color(hl);
                ctx.begin_path();
                ctx.rect(fx, line_bottom_up, frag.width, line.height);
                ctx.fill();
            }
            let color = frag.style.text_color.unwrap_or(default_color);
            ctx.set_font(Arc::clone(&frag.font));
            ctx.set_font_size(frag.font_size);
            ctx.set_fill_color(color);
            ctx.fill_text(&frag.text, fx, baseline_up);

            if frag.style.underline || frag.style.strikethrough {
                ctx.set_stroke_color(color);
                ctx.set_line_width(1.0_f64.max(frag.font_size * 0.06));
            }
            if frag.style.underline {
                let uy = baseline_up - (frag.font_size * 0.12).max(1.5);
                stroke_hline(ctx, fx, fx + frag.width, uy);
            }
            if frag.style.strikethrough {
                let sy = baseline_up + frag.font_size * 0.28;
                stroke_hline(ctx, fx, fx + frag.width, sy);
            }
        }
    }

    /// Paint the blinking caret in the overlay pass (clipped to the inner band).
    pub(super) fn paint_caret(&mut self, ctx: &mut dyn DrawCtx) {
        if !self.focused {
            return;
        }
        if let Some(t) = self.focus_time {
            let phase = (t.elapsed().as_millis() / 500) as u64;
            self.blink_last_phase.set(phase);
            if phase % 2 == 1 {
                return;
            }
        }
        let caret = self.core.borrow().caret();
        let Some(geom) = self.caret_geometry(caret) else {
            return;
        };
        // Clamp the caret's vertical span to the padded inner band so it never
        // streaks over the border when its line has scrolled out of view.
        let inner_lo = self.padding;
        let inner_hi = (self.bounds.height - self.padding).max(inner_lo);
        let y0 = geom.y_bottom.max(inner_lo);
        let y1 = (geom.y_bottom + geom.height).min(inner_hi);
        if y1 <= y0 {
            return;
        }
        let v = ctx.visuals();
        ctx.set_stroke_color(v.text_color);
        ctx.set_line_width(1.5);
        ctx.begin_path();
        ctx.move_to(geom.x, y0);
        ctx.line_to(geom.x, y1);
        ctx.stroke();
    }
}

/// Stroke a 1px-ish horizontal line at Y-up `y` from `x0` to `x1`.
fn stroke_hline(ctx: &mut dyn DrawCtx, x0: f64, x1: f64, y: f64) {
    ctx.begin_path();
    ctx.move_to(x0, y);
    ctx.line_to(x1, y);
    ctx.stroke();
}