iced_graphics/geometry/
text.rs

1use crate::core;
2use crate::core::alignment;
3use crate::core::text::{Alignment, Ellipsis, LineHeight, Paragraph, Shaping, Wrapping};
4use crate::core::{Color, Font, Pixels, Point, Size, Vector};
5use crate::geometry::Path;
6use crate::text;
7
8/// A bunch of text that can be drawn to a canvas
9#[derive(Debug, Clone)]
10pub struct Text {
11    /// The contents of the text
12    pub content: String,
13    /// The position of the text relative to the alignment properties.
14    ///
15    /// By default, this position will be relative to the top-left corner coordinate meaning that
16    /// if the horizontal and vertical alignments are unchanged, this property will tell where the
17    /// top-left corner of the text should be placed.
18    ///
19    /// By changing the horizontal_alignment and vertical_alignment properties, you are are able to
20    /// change what part of text is placed at this positions.
21    ///
22    /// For example, when the horizontal_alignment and vertical_alignment are set to Center, the
23    /// center of the text will be placed at the given position NOT the top-left coordinate.
24    pub position: Point,
25    /// The maximum horizontal space available for this [`Text`].
26    ///
27    /// Text will break into new lines when the width is reached.
28    pub max_width: f32,
29    /// The color of the text
30    pub color: Color,
31    /// The size of the text
32    pub size: Pixels,
33    /// The line height of the text.
34    pub line_height: LineHeight,
35    /// The font of the text
36    pub font: Font,
37    /// The horizontal alignment of the text
38    pub align_x: Alignment,
39    /// The vertical alignment of the text
40    pub align_y: alignment::Vertical,
41    /// The shaping strategy of the text.
42    pub shaping: Shaping,
43    /// The wrapping strategy of the text.
44    pub wrapping: Wrapping,
45    /// The ellipsis strategy of the text.
46    pub ellipsis: Ellipsis,
47}
48
49impl Text {
50    /// Computes the [`Path`]s of the [`Text`] and draws them using
51    /// the given closure.
52    pub fn draw_with(&self, mut f: impl FnMut(Path, Color)) {
53        let paragraph = text::Paragraph::with_text(core::text::Text {
54            content: &self.content,
55            bounds: Size::new(self.max_width, f32::INFINITY),
56            size: self.size,
57            line_height: self.line_height,
58            font: self.font,
59            align_x: self.align_x,
60            align_y: self.align_y,
61            shaping: self.shaping,
62            wrapping: Wrapping::default(),
63            ellipsis: Ellipsis::default(),
64            hint_factor: None,
65        });
66
67        let translation_x = match self.align_x {
68            Alignment::Default | Alignment::Left | Alignment::Justified => self.position.x,
69            Alignment::Center => self.position.x - paragraph.min_width() / 2.0,
70            Alignment::Right => self.position.x - paragraph.min_width(),
71        };
72
73        let translation_y = {
74            match self.align_y {
75                alignment::Vertical::Top => self.position.y,
76                alignment::Vertical::Center => self.position.y - paragraph.min_height() / 2.0,
77                alignment::Vertical::Bottom => self.position.y - paragraph.min_height(),
78            }
79        };
80
81        let buffer = paragraph.buffer();
82        let mut swash_cache = cosmic_text::SwashCache::new();
83
84        let mut font_system = text::font_system().write().expect("Write font system");
85
86        for run in buffer.layout_runs() {
87            for glyph in run.glyphs.iter() {
88                let physical_glyph = glyph.physical((0.0, 0.0), 1.0);
89
90                let start_x = translation_x + glyph.x + glyph.x_offset;
91                let start_y = translation_y + glyph.y_offset + run.line_y;
92                let offset = Vector::new(start_x, start_y);
93
94                if let Some(commands) =
95                    swash_cache.get_outline_commands(font_system.raw(), physical_glyph.cache_key)
96                {
97                    let glyph = Path::new(|path| {
98                        use cosmic_text::Command;
99
100                        for command in commands {
101                            match command {
102                                Command::MoveTo(p) => {
103                                    path.move_to(Point::new(p.x, -p.y) + offset);
104                                }
105                                Command::LineTo(p) => {
106                                    path.line_to(Point::new(p.x, -p.y) + offset);
107                                }
108                                Command::CurveTo(control_a, control_b, to) => {
109                                    path.bezier_curve_to(
110                                        Point::new(control_a.x, -control_a.y) + offset,
111                                        Point::new(control_b.x, -control_b.y) + offset,
112                                        Point::new(to.x, -to.y) + offset,
113                                    );
114                                }
115                                Command::QuadTo(control, to) => {
116                                    path.quadratic_curve_to(
117                                        Point::new(control.x, -control.y) + offset,
118                                        Point::new(to.x, -to.y) + offset,
119                                    );
120                                }
121                                Command::Close => {
122                                    path.close();
123                                }
124                            }
125                        }
126                    });
127
128                    f(glyph, self.color);
129                } else {
130                    // TODO: Raster image support for `Canvas`
131                    let [r, g, b, a] = self.color.into_rgba8();
132
133                    swash_cache.with_pixels(
134                        font_system.raw(),
135                        physical_glyph.cache_key,
136                        cosmic_text::Color::rgba(r, g, b, a),
137                        |x, y, color| {
138                            f(
139                                Path::rectangle(
140                                    Point::new(x as f32, y as f32) + offset,
141                                    Size::new(1.0, 1.0),
142                                ),
143                                Color::from_rgba8(
144                                    color.r(),
145                                    color.g(),
146                                    color.b(),
147                                    color.a() as f32 / 255.0,
148                                ),
149                            );
150                        },
151                    );
152                }
153            }
154        }
155    }
156}
157
158impl Default for Text {
159    fn default() -> Text {
160        Text {
161            content: String::new(),
162            position: Point::ORIGIN,
163            max_width: f32::INFINITY,
164            color: Color::BLACK,
165            size: Pixels(16.0),
166            line_height: LineHeight::Relative(1.2),
167            font: Font::default(),
168            align_x: Alignment::Default,
169            align_y: alignment::Vertical::Top,
170            shaping: Shaping::default(),
171            wrapping: Wrapping::default(),
172            ellipsis: Ellipsis::default(),
173        }
174    }
175}
176
177impl From<String> for Text {
178    fn from(content: String) -> Text {
179        Text {
180            content,
181            ..Default::default()
182        }
183    }
184}
185
186impl From<&str> for Text {
187    fn from(content: &str) -> Text {
188        String::from(content).into()
189    }
190}
iced_graphics/geometry/text.rs

iced_graphics/geometry/
text.rs
