typst/src/layout/elements.rs

84 lines
2.2 KiB
Rust

//! Basic building blocks of layouts.
use std::fmt::{self, Debug, Formatter};
use fontdock::FaceId;
use ttf_parser::GlyphId;
use crate::geom::Point;
/// A collection of absolutely positioned layout elements.
#[derive(Debug, Default, Clone, PartialEq)]
pub struct LayoutElements(pub Vec<(Point, LayoutElement)>);
impl LayoutElements {
/// Create an new empty collection.
pub fn new() -> Self {
Self(vec![])
}
/// Add an element at a position.
pub fn push(&mut self, pos: Point, element: LayoutElement) {
self.0.push((pos, element));
}
/// Add all elements of another collection, placing them relative to the
/// given position.
pub fn push_elements(&mut self, pos: Point, more: Self) {
for (subpos, element) in more.0 {
self.0.push((pos + subpos.to_vec2(), element));
}
}
}
/// A layout element, the basic building block layouts are composed of.
#[derive(Debug, Clone, PartialEq)]
pub enum LayoutElement {
Text(Shaped),
}
/// A shaped run of text.
#[derive(Clone, PartialEq)]
pub struct Shaped {
/// The shaped text.
pub text: String,
/// The font face the text was shaped with.
pub face: FaceId,
/// The shaped glyphs.
pub glyphs: Vec<GlyphId>,
/// The horizontal offsets of the glyphs. This is indexed parallel to `glyphs`.
/// Vertical offets are not yet supported.
pub offsets: Vec<f64>,
/// The font size.
pub size: f64,
}
impl Shaped {
/// Create a new shape run with empty `text`, `glyphs` and `offsets`.
pub fn new(face: FaceId, size: f64) -> Self {
Self {
text: String::new(),
face,
glyphs: vec![],
offsets: vec![],
size,
}
}
/// 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 &GlyphId(g) in &self.glyphs {
bytes.push((g >> 8) as u8);
bytes.push((g & 0xff) as u8);
}
bytes
}
}
impl Debug for Shaped {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "Shaped({})", self.text)
}
}