Refactor SVG export a bit

crates/typst-cli/src/compile.rs

@@ -95,19 +95,14 @@ pub fn compile_once(
     Ok(())
 }
 
-enum ExportImageFormat {
-    Png,
-    Svg,
-}
-
 /// Export into the target format.
 fn export(document: &Document, command: &CompileCommand) -> StrResult<()> {
     match command.output().extension() {
         Some(ext) if ext.eq_ignore_ascii_case("png") => {
-            export_image(document, command, ExportImageFormat::Png)
+            export_image(document, command, ImageExportFormat::Png)
         }
         Some(ext) if ext.eq_ignore_ascii_case("svg") => {
-            export_image(document, command, ExportImageFormat::Svg)
+            export_image(document, command, ImageExportFormat::Svg)
         }
         _ => export_pdf(document, command),
     }
@@ -121,18 +116,24 @@ fn export_pdf(document: &Document, command: &CompileCommand) -> StrResult<()> {
     Ok(())
 }
 
+/// An image format to export in.
+enum ImageExportFormat {
+    Png,
+    Svg,
+}
+
 /// Export to one or multiple PNGs.
 fn export_image(
     document: &Document,
     command: &CompileCommand,
-    fmt: ExportImageFormat,
+    fmt: ImageExportFormat,
 ) -> StrResult<()> {
     // Determine whether we have a `{n}` numbering.
     let output = command.output();
     let string = output.to_str().unwrap_or_default();
     let numbered = string.contains("{n}");
     if !numbered && document.pages.len() > 1 {
-        bail!("cannot export multiple PNGs without `{{n}}` in output path");
+        bail!("cannot export multiple images without `{{n}}` in output path");
     }
 
     // Find a number width that accommodates all pages. For instance, the
@@ -149,13 +150,13 @@ fn export_image(
             output.as_path()
         };
         match fmt {
-            ExportImageFormat::Png => {
+            ImageExportFormat::Png => {
                 let pixmap =
                     typst::export::render(frame, command.ppi / 72.0, Color::WHITE);
                 pixmap.save_png(path).map_err(|_| "failed to write PNG file")?;
             }
-            ExportImageFormat::Svg => {
-                let svg = typst::export::svg_frame(frame);
+            ImageExportFormat::Svg => {
+                let svg = typst::export::svg(frame);
                 fs::write(path, svg).map_err(|_| "failed to write SVG file")?;
             }
         }

crates/typst/src/export/mod.rs

@@ -5,5 +5,5 @@ mod render;
 mod svg;
 
 pub use self::pdf::pdf;
-pub use self::render::render;
-pub use self::svg::{svg, svg_frame};
+pub use self::render::{render, render_merged};
+pub use self::svg::{svg, svg_merged};

crates/typst/src/export/render.rs

@@ -37,6 +37,47 @@ pub fn render(frame: &Frame, pixel_per_pt: f32, fill: Color) -> sk::Pixmap {
     canvas
 }
 
+/// Export multiple frames into a single raster image.
+///
+/// The padding will be added around and between the individual frames.
+pub fn render_merged(
+    frames: &[Frame],
+    pixel_per_pt: f32,
+    frame_fill: Color,
+    padding: Abs,
+    padding_fill: Color,
+) -> sk::Pixmap {
+    let pixmaps: Vec<_> = frames
+        .iter()
+        .map(|frame| typst::export::render(frame, pixel_per_pt, frame_fill))
+        .collect();
+
+    let padding = (pixel_per_pt * padding.to_f32()).round() as u32;
+    let pxw =
+        2 * padding + pixmaps.iter().map(sk::Pixmap::width).max().unwrap_or_default();
+    let pxh =
+        padding + pixmaps.iter().map(|pixmap| pixmap.height() + padding).sum::<u32>();
+
+    let mut canvas = sk::Pixmap::new(pxw, pxh).unwrap();
+    canvas.fill(padding_fill.into());
+
+    let [x, mut y] = [padding; 2];
+    for pixmap in pixmaps {
+        canvas.draw_pixmap(
+            x as i32,
+            y as i32,
+            pixmap.as_ref(),
+            &sk::PixmapPaint::default(),
+            sk::Transform::identity(),
+            None,
+        );
+
+        y += pixmap.height() + padding;
+    }
+
+    canvas
+}
+
 /// Render a frame into the canvas.
 fn render_frame(
     canvas: &mut sk::Pixmap,

tests/src/tests.rs

@@ -429,7 +429,7 @@ fn test(
         fs::create_dir_all(png_path.parent().unwrap()).unwrap();
         canvas.save_png(png_path).unwrap();
 
-        let svg = typst::export::svg(&document);
+        let svg = typst::export::svg_merged(&document.pages, Abs::pt(5.0));
         fs::create_dir_all(svg_path.parent().unwrap()).unwrap();
         std::fs::write(svg_path, svg).unwrap();
 
@@ -898,42 +898,33 @@ fn test_spans_impl(output: &mut String, node: &SyntaxNode, within: Range<u64>) -
 /// Draw all frames into one image with padding in between.
 fn render(frames: &[Frame]) -> sk::Pixmap {
     let pixel_per_pt = 2.0;
-    let pixmaps: Vec<_> = frames
-        .iter()
-        .map(|frame| {
-            let limit = Abs::cm(100.0);
-            if frame.width() > limit || frame.height() > limit {
-                panic!("overlarge frame: {:?}", frame.size());
-            }
-            typst::export::render(frame, pixel_per_pt, Color::WHITE)
-        })
-        .collect();
+    let padding = Abs::pt(5.0);
 
-    let pad = (5.0 * pixel_per_pt).round() as u32;
-    let pxw = 2 * pad + pixmaps.iter().map(sk::Pixmap::width).max().unwrap_or_default();
-    let pxh = pad + pixmaps.iter().map(|pixmap| pixmap.height() + pad).sum::<u32>();
-
-    let mut canvas = sk::Pixmap::new(pxw, pxh).unwrap();
-    canvas.fill(sk::Color::BLACK);
-
-    let [x, mut y] = [pad; 2];
-    for (frame, mut pixmap) in frames.iter().zip(pixmaps) {
-        let ts = sk::Transform::from_scale(pixel_per_pt, pixel_per_pt);
-        render_links(&mut pixmap, ts, frame);
-
-        canvas.draw_pixmap(
-            x as i32,
-            y as i32,
-            pixmap.as_ref(),
-            &sk::PixmapPaint::default(),
-            sk::Transform::identity(),
-            None,
-        );
-
-        y += pixmap.height() + pad;
+    for frame in frames {
+        let limit = Abs::cm(100.0);
+        if frame.width() > limit || frame.height() > limit {
+            panic!("overlarge frame: {:?}", frame.size());
+        }
     }
 
-    canvas
+    let mut pixmap = typst::export::render_merged(
+        frames,
+        pixel_per_pt,
+        Color::WHITE,
+        padding,
+        Color::BLACK,
+    );
+
+    let padding = (pixel_per_pt * padding.to_pt() as f32).round();
+    let [x, mut y] = [padding; 2];
+    for frame in frames {
+        let ts =
+            sk::Transform::from_scale(pixel_per_pt, pixel_per_pt).post_translate(x, y);
+        render_links(&mut pixmap, ts, frame);
+        y += (pixel_per_pt * frame.height().to_pt() as f32).round().max(1.0) + padding;
+    }
+
+    pixmap
 }
 
 /// Draw extra boxes for links so we can see whether they are there.