typst/src/library/transform.rs
2021-12-30 12:12:19 +01:00

72 lines
2.3 KiB
Rust

//! Affine transformations on nodes.
use super::prelude::*;
use crate::geom::Transform;
/// `move`: Move content without affecting layout.
pub fn move_(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
let tx = args.named("x")?.unwrap_or_default();
let ty = args.named("y")?.unwrap_or_default();
let transform = Transform::translation(tx, ty);
transform_impl(args, transform)
}
/// `scale`: Scale content without affecting layout.
pub fn scale(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
let all = args.find();
let sx = args.named("x")?.or(all).unwrap_or(Relative::one());
let sy = args.named("y")?.or(all).unwrap_or(Relative::one());
let transform = Transform::scaling(sx, sy);
transform_impl(args, transform)
}
/// `rotate`: Rotate content without affecting layout.
pub fn rotate(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
let angle = args.named("angle")?.or_else(|| args.find()).unwrap_or_default();
let transform = Transform::rotation(angle);
transform_impl(args, transform)
}
fn transform_impl(args: &mut Args, transform: Transform) -> TypResult<Value> {
let body: PackedNode = args.expect("body")?;
let origin = args
.named("origin")?
.unwrap_or(Spec::splat(None))
.unwrap_or(Align::CENTER_HORIZON);
Ok(Value::inline(body.transformed(transform, origin)))
}
/// A node that transforms its child without affecting layout.
#[derive(Debug, Hash)]
pub struct TransformNode {
/// Transformation to apply to the contents.
pub transform: Transform,
/// The origin of the transformation.
pub origin: Spec<Align>,
/// The node whose contents should be transformed.
pub child: PackedNode,
}
impl Layout for TransformNode {
fn layout(
&self,
ctx: &mut LayoutContext,
regions: &Regions,
styles: StyleChain,
) -> Vec<Constrained<Rc<Frame>>> {
let mut frames = self.child.layout(ctx, regions, styles);
for Constrained { item: frame, .. } in &mut frames {
let Spec { x, y } = self.origin.zip(frame.size).map(|(o, s)| o.resolve(s));
let transform = Transform::translation(x, y)
.pre_concat(self.transform)
.pre_concat(Transform::translation(-x, -y));
Rc::make_mut(frame).transform(transform);
}
frames
}
}