mirror of
https://github.com/typst/typst
synced 2025-05-13 20:46:23 +08:00
89 lines
3.0 KiB
Rust
89 lines
3.0 KiB
Rust
use ::image::GenericImageView;
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use super::*;
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use crate::env::{ImageResource, ResourceId};
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use crate::layout::{AnyNode, Areas, Element, Frame, Image, Layout, LayoutContext};
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/// `image`: An image.
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///
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/// Supports PNG and JPEG files.
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///
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/// # Positional parameters
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/// - Path to image file: of type `string`.
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///
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/// # Return value
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/// A template that inserts an image.
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pub fn image(ctx: &mut EvalContext, args: &mut FuncArgs) -> Value {
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let path = args.require::<Spanned<String>>(ctx, "path to image file");
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let width = args.get(ctx, "width");
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let height = args.get(ctx, "height");
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Value::template("image", move |ctx| {
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if let Some(path) = &path {
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let loaded = ctx.env.load_resource(&path.v, ImageResource::parse);
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if let Some(id) = loaded {
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let img = ctx.env.resource::<ImageResource>(id);
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let dimensions = img.buf.dimensions();
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ctx.push(ImageNode { id, dimensions, width, height });
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} else {
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ctx.diag(error!(path.span, "failed to load image"));
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}
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}
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})
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}
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/// An image node.
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#[derive(Debug, Clone, PartialEq)]
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struct ImageNode {
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/// The resource id of the image file.
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id: ResourceId,
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/// The pixel dimensions of the image.
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dimensions: (u32, u32),
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/// The fixed width, if any.
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width: Option<Linear>,
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/// The fixed height, if any.
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height: Option<Linear>,
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}
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impl Layout for ImageNode {
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fn layout(&self, _: &mut LayoutContext, areas: &Areas) -> Vec<Frame> {
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let Areas { current, full, .. } = areas;
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let pixel_width = self.dimensions.0 as f64;
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let pixel_height = self.dimensions.1 as f64;
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let pixel_ratio = pixel_width / pixel_height;
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let width = self.width.map(|w| w.resolve(full.width));
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let height = self.height.map(|w| w.resolve(full.height));
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let size = match (width, height) {
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(Some(width), Some(height)) => Size::new(width, height),
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(Some(width), None) => Size::new(width, width / pixel_ratio),
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(None, Some(height)) => Size::new(height * pixel_ratio, height),
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(None, None) => {
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let ratio = current.width / current.height;
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if ratio < pixel_ratio && current.width.is_finite() {
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Size::new(current.width, current.width / pixel_ratio)
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} else if current.height.is_finite() {
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// TODO: Fix issue with line spacing.
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Size::new(current.height * pixel_ratio, current.height)
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} else {
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// Totally unbounded area, we have to make up something.
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Size::new(Length::pt(pixel_width), Length::pt(pixel_height))
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}
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}
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};
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let mut frame = Frame::new(size, size.height);
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frame.push(Point::ZERO, Element::Image(Image { id: self.id, size }));
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vec![frame]
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}
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}
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impl From<ImageNode> for AnyNode {
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fn from(image: ImageNode) -> Self {
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Self::new(image)
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}
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}
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