iced_graphics/geometry/text.rs
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use crate::core::alignment;
use crate::core::text::{LineHeight, Shaping};
use crate::core::{Color, Font, Pixels, Point, Size, Vector};
use crate::geometry::Path;
use crate::text;
/// A bunch of text that can be drawn to a canvas
#[derive(Debug, Clone)]
pub struct Text {
/// The contents of the text
pub content: String,
/// The position of the text relative to the alignment properties.
/// By default, this position will be relative to the top-left corner coordinate meaning that
/// if the horizontal and vertical alignments are unchanged, this property will tell where the
/// top-left corner of the text should be placed.
/// By changing the horizontal_alignment and vertical_alignment properties, you are are able to
/// change what part of text is placed at this positions.
/// For example, when the horizontal_alignment and vertical_alignment are set to Center, the
/// center of the text will be placed at the given position NOT the top-left coordinate.
pub position: Point,
/// The color of the text
pub color: Color,
/// The size of the text
pub size: Pixels,
/// The line height of the text.
pub line_height: LineHeight,
/// The font of the text
pub font: Font,
/// The horizontal alignment of the text
pub horizontal_alignment: alignment::Horizontal,
/// The vertical alignment of the text
pub vertical_alignment: alignment::Vertical,
/// The shaping strategy of the text.
pub shaping: Shaping,
}
impl Text {
/// Computes the [`Path`]s of the [`Text`] and draws them using
/// the given closure.
pub fn draw_with(&self, mut f: impl FnMut(Path, Color)) {
let mut font_system =
text::font_system().write().expect("Write font system");
let mut buffer = cosmic_text::BufferLine::new(
&self.content,
cosmic_text::LineEnding::default(),
cosmic_text::AttrsList::new(text::to_attributes(self.font)),
text::to_shaping(self.shaping),
);
let layout = buffer.layout(
font_system.raw(),
self.size.0,
None,
cosmic_text::Wrap::None,
None,
4,
);
let translation_x = match self.horizontal_alignment {
alignment::Horizontal::Left => self.position.x,
alignment::Horizontal::Center | alignment::Horizontal::Right => {
let mut line_width = 0.0f32;
for line in layout.iter() {
line_width = line_width.max(line.w);
}
if self.horizontal_alignment == alignment::Horizontal::Center {
self.position.x - line_width / 2.0
} else {
self.position.x - line_width
}
}
};
let translation_y = {
let line_height = self.line_height.to_absolute(self.size);
match self.vertical_alignment {
alignment::Vertical::Top => self.position.y,
alignment::Vertical::Center => {
self.position.y - line_height.0 / 2.0
}
alignment::Vertical::Bottom => self.position.y - line_height.0,
}
};
let mut swash_cache = cosmic_text::SwashCache::new();
for run in layout.iter() {
for glyph in run.glyphs.iter() {
let physical_glyph = glyph.physical((0.0, 0.0), 1.0);
let start_x = translation_x + glyph.x + glyph.x_offset;
let start_y = translation_y + glyph.y_offset + self.size.0;
let offset = Vector::new(start_x, start_y);
if let Some(commands) = swash_cache.get_outline_commands(
font_system.raw(),
physical_glyph.cache_key,
) {
let glyph = Path::new(|path| {
use cosmic_text::Command;
for command in commands {
match command {
Command::MoveTo(p) => {
path.move_to(
Point::new(p.x, -p.y) + offset,
);
}
Command::LineTo(p) => {
path.line_to(
Point::new(p.x, -p.y) + offset,
);
}
Command::CurveTo(control_a, control_b, to) => {
path.bezier_curve_to(
Point::new(control_a.x, -control_a.y)
+ offset,
Point::new(control_b.x, -control_b.y)
+ offset,
Point::new(to.x, -to.y) + offset,
);
}
Command::QuadTo(control, to) => {
path.quadratic_curve_to(
Point::new(control.x, -control.y)
+ offset,
Point::new(to.x, -to.y) + offset,
);
}
Command::Close => {
path.close();
}
}
}
});
f(glyph, self.color);
} else {
// TODO: Raster image support for `Canvas`
let [r, g, b, a] = self.color.into_rgba8();
swash_cache.with_pixels(
font_system.raw(),
physical_glyph.cache_key,
cosmic_text::Color::rgba(r, g, b, a),
|x, y, color| {
f(
Path::rectangle(
Point::new(x as f32, y as f32) + offset,
Size::new(1.0, 1.0),
),
Color::from_rgba8(
color.r(),
color.g(),
color.b(),
color.a() as f32 / 255.0,
),
);
},
);
}
}
}
}
}
impl Default for Text {
fn default() -> Text {
Text {
content: String::new(),
position: Point::ORIGIN,
color: Color::BLACK,
size: Pixels(16.0),
line_height: LineHeight::Relative(1.2),
font: Font::default(),
horizontal_alignment: alignment::Horizontal::Left,
vertical_alignment: alignment::Vertical::Top,
shaping: Shaping::Basic,
}
}
}
impl From<String> for Text {
fn from(content: String) -> Text {
Text {
content,
..Default::default()
}
}
}
impl From<&str> for Text {
fn from(content: &str) -> Text {
String::from(content).into()
}
}