typst/src/layout/frame.rs

111 lines
3.1 KiB
Rust

use crate::color::Color;
use crate::font::FaceId;
use crate::geom::{Length, Path, Point, Size};
use crate::image::ImageId;
use serde::{Deserialize, Serialize};
/// A finished layout with elements at fixed positions.
#[derive(Default, Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct Frame {
/// The size of the frame.
pub size: Size,
/// The baseline of the frame measured from the top.
pub baseline: Length,
/// The elements composing this layout.
pub elements: Vec<(Point, Element)>,
}
impl Frame {
/// Create a new, empty frame.
pub fn new(size: Size, baseline: Length) -> Self {
assert!(size.is_finite());
Self { size, baseline, elements: vec![] }
}
/// Add an element at a position.
pub fn push(&mut self, pos: Point, element: Element) {
self.elements.push((pos, element));
}
/// Add all elements of another frame, placing them relative to the given
/// position.
pub fn push_frame(&mut self, pos: Point, subframe: Self) {
if pos == Point::zero() && self.elements.is_empty() {
self.elements = subframe.elements;
} else {
for (subpos, element) in subframe.elements {
self.push(pos + subpos, element);
}
}
}
}
/// The building block frames are composed of.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum Element {
/// Shaped text.
Text(Text),
/// A filled geometric shape.
Geometry(Shape, Fill),
/// A raster image.
Image(ImageId, Size),
}
/// A run of shaped text.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct Text {
/// The font face the glyphs are contained in.
pub face_id: FaceId,
/// The font size.
pub size: Length,
/// The glyph's fill color.
pub fill: Fill,
/// The glyphs.
pub glyphs: Vec<Glyph>,
}
/// A glyph in a run of shaped text.
#[derive(Debug, Copy, Clone, PartialEq, Serialize, Deserialize)]
pub struct Glyph {
/// The glyph's index in the face.
pub id: u16,
/// The advance width of the glyph.
pub x_advance: Length,
/// The horizontal offset of the glyph.
pub x_offset: Length,
}
impl Text {
/// Encode the glyph ids into a big-endian byte buffer.
pub fn encode_glyphs_be(&self) -> Vec<u8> {
let mut bytes = Vec::with_capacity(2 * self.glyphs.len());
for glyph in &self.glyphs {
let id = glyph.id;
bytes.push((id >> 8) as u8);
bytes.push((id & 0xff) as u8);
}
bytes
}
}
/// A geometric shape.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum Shape {
/// A rectangle with its origin in the topleft corner.
Rect(Size),
/// An ellipse with its origin in the center.
Ellipse(Size),
/// A line to a `Point` (relative to its position) with a stroke width.
Line(Point, Length),
/// A bezier path.
Path(Path),
}
/// How text and shapes are filled.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash, Serialize, Deserialize)]
pub enum Fill {
/// A solid color.
Color(Color),
}