✨ Support skia pdf rendering

frontend/src/app/main/data/exports/assets.cljs

@@ -166,11 +166,13 @@
 (defn request-simple-export
   [{:keys [export]}]
   (if (and (contains? cf/flags :wasm-export)
-           (contains? #{:jpeg :webp :png} (:type export)))
+           (contains? #{:jpeg :webp :png :pdf} (:type export)))
     (ptk/reify ::request-simple-export-wasm
       ptk/EffectEvent
       (effect [_ _ _]
-        (wasm.exports/export-image export)))
+        (case (:type export)
+          :pdf (wasm.exports/export-pdf export)
+          (wasm.exports/export-image export))))
 
     (ptk/reify ::request-simple-export
       ptk/UpdateEvent

frontend/src/app/main/data/exports/wasm.cljs

@@ -26,3 +26,18 @@
     (dom/trigger-download-uri filename mtype url)
     (wapi/revoke-uri url)
     nil))
+
+(defn export-pdf-uri
+  [{:keys [scale object-id]}]
+  (let [bytes (wasm.api/render-shape-pdf object-id (or scale 1))
+        blob (wapi/create-blob bytes "application/pdf")]
+    (wapi/create-uri blob)))
+
+(defn export-pdf
+  [{:keys [suffix name] :as params}]
+  (let [url (export-pdf-uri params)
+        filename (str name (or suffix "") ".pdf")]
+    (dom/trigger-download-uri filename "application/pdf" url)
+    (wapi/revoke-uri url)
+    nil))
+

frontend/src/app/render_wasm/api.cljs

@@ -2267,6 +2267,25 @@
         (mem/free)
         {:x x :y y :width w :height h}))))
 
+(defn render-shape-pdf
+  [shape-id scale]
+  (let [buffer (uuid/get-u32 shape-id)
+
+        offset
+        (h/call wasm/internal-module "_render_shape_pdf"
+                (aget buffer 0)
+                (aget buffer 1)
+                (aget buffer 2)
+                (aget buffer 3)
+                scale)
+
+        heap (mem/get-heap-u8)
+        heapu32 (mem/get-heap-u32)
+        length (aget heapu32 (mem/->offset-32 offset))
+        result (dr/read-image-bytes heap (+ offset 4) length)]
+    (mem/free)
+    result))
+
 (defn init-wasm-module
   [module]
   (let [default-fn (unchecked-get module "default")

render-wasm/Cargo.toml

@@ -32,6 +32,7 @@ skia-safe = { version = "0.93.1", default-features = false, features = [
   "textlayout",
   "binary-cache",
   "webp",
+  "pdf",
 ] }
 thiserror = "2.0.18"
 uuid = { version = "1.11.0", features = ["v4", "js"] }

render-wasm/README.md

@@ -52,6 +52,7 @@ cd penpot/render-wasm
 
 ## Technical documentation
 
+- [Rendering Architecture (Live vs Vector/PDF)](./docs/rendering_architecture.md)
 - [Serialization](./docs/serialization.md)
 - [Tile Rendering](./docs/tile_rendering.md)
 - [Texts](./docs/texts.md)

render-wasm/docs/rendering_architecture.md

@@ -0,0 +1,133 @@
+# Rendering Architecture: Live (GPU) vs Vector (PDF) Export
+
+Penpot's WASM engine has **two render paths** that must produce the same picture:
+
+| Path | Purpose | Backend | Code |
+|------|---------|---------|------|
+| **Live / GPU** | On-screen workspace, thumbnails, PNG export | WebGL surfaces + Skia | `render.rs::render_shape` (+ `render/{fills,strokes,shadows,text,...}.rs`) |
+| **Vector** | True vector PDF (and future SVG) export | Single CPU Skia canvas (no GPU) | `render/vector.rs` → `render/pdf.rs` |
+
+They share the same shape tree and the same low-level drawing primitives, but
+compose them differently. Keeping them in sync is the whole game — see
+[Parity guards](#parity-guards).
+
+## Why two paths?
+
+The live path draws each shape into **many intermediate GPU surfaces** (fills,
+strokes, shadows, …) and composites them. Compositing rasterises. That is fine
+for the screen and for PNG, but a PDF made that way would be a bitmap.
+
+The vector path bypasses the GPU surface system and draws **directly onto a
+Skia PDF canvas**, so paths, text and fills come out as real PDF vector
+operations. Only inherently pixel-based effects (blur, blurred shadows) are
+rasterised — by Skia's PDF backend, by design.
+
+## The two pipelines
+
+```mermaid
+flowchart TB
+    tree["Shape tree (ShapesPool)"]
+
+    subgraph GPU["Live / GPU path — render.rs"]
+        direction TB
+        g0["render_shape(shape)"]
+        g1["fast_mode? can_render_directly?<br/>tiles, clip stacks, nested fills/blurs"]
+        gF["fills::render → Surface::Fills"]
+        gS["strokes::render → Surface::Strokes"]
+        gI["shadows::* → Surface::InnerShadows"]
+        gD["drop shadows (tree level)<br/>→ Surface::DropShadows"]
+        gC["draw_shape_surface_stack_into<br/>composite surfaces → final z-order"]
+        g0 --> g1 --> gF --> gS --> gI --> gC
+        gD --> gC
+    end
+
+    subgraph SHARED["Shared primitives (one source of truth)"]
+        p1["draw_stroke_on_rect / draw_stroke_on_circle"]
+        p2["handle_stroke_caps (arrows, markers)"]
+        p3["render_inner_stroke / render_overlay_emoji (text)"]
+    end
+
+    subgraph VEC["Vector path — render/vector.rs"]
+        direction TB
+        v0["render_to_pdf → render_tree(shape)"]
+        v1["render_group / render_frame / render_leaf<br/>concat centered_transform, save_layer for opacity/blur"]
+        v2["draw_drop_shadows (inline)"]
+        v3["render_leaf_content&lt;R: ShapeRenderer&gt;<br/>fills → fill inner shadows → strokes → stroke inner shadows"]
+        v4["one Skia PDF canvas<br/>final z = draw call order"]
+        v0 --> v1 --> v2 --> v3 --> v4
+    end
+
+    tree --> g0
+    tree --> v0
+
+    gS -.uses.-> SHARED
+    v3 -.uses.-> SHARED
+```
+
+### Key differences
+
+| Aspect | Live / GPU | Vector |
+|--------|-----------|--------|
+| Drawing target | Many GPU surfaces, then composited | One Skia PDF canvas |
+| Final z-order | Surface composite order (`draw_shape_surface_stack_into`) | Order of draw calls |
+| Drop shadows | Rendered at tree level into a separate surface (`render_element_drop_shadows_and_composite`) | Drawn inline per shape/container (`draw_drop_shadows` / `render_container_drop_shadows`) |
+| Images | GPU textures | CPU image copies (`get_cpu_image`) |
+| Blur / blurred shadow | GPU filter passes | Rasterised by Skia's PDF backend |
+| Perf machinery | tiles, `fast_mode`, `can_render_directly` | none (one-shot export) |
+
+## Transforms (important)
+
+Both paths place a shape at the same world coordinates, but reach it
+differently. For Path/Bool shapes:
+
+- `centered_transform` (**C**) and `to_path_transform` (**P**) are exact
+  inverses: `C · P = I`.
+- `get_skia_path()` already bakes **P** into the geometry (`P · raw`).
+- Live: canvas carries **C**, draws `get_skia_path()` → `C · P · raw = raw`.
+- Vector: same — `render_leaf` concats **C**, `draw_shape_geometry` draws
+  `get_skia_path()` directly. **Do not re-apply `to_path_transform`** — that
+  double-counts and mis-positions/rotates the shape.
+
+## Parity guards
+
+Three compile-time guards plus shared code keep the two paths from drifting.
+The contract is documented on the `ShapeRenderer` trait
+(`render/shape_renderer.rs`).
+
+1. **Capability guard.** `ShapeRenderer` is the single declaration of per-shape
+   rendering capabilities (`draw_fills`, `draw_strokes`, `draw_drop_shadows`,
+   …). A new effect MUST be added as a trait method, not inline in
+   `render_shape`. Adding a method fails to compile until the vector backend
+   handles it — so a feature can never be silently missing from PDF.
+2. **Type guard.** Every `match` on `shape.shape_type` in `vector.rs` is
+   exhaustive (no `_ =>`). A new `Type` variant fails to compile until handled.
+3. **Order guard.** Leaf content draw order/gating lives in exactly one place:
+   `vector::render_leaf_content<R: ShapeRenderer>`. It is generic over the
+   trait so the GPU backend can reuse it verbatim once it implements
+   `ShapeRenderer`.
+4. **Shared primitives.** Prefer reusing the live-render functions over
+   mirroring them: `draw_stroke_on_rect`, `draw_stroke_on_circle`,
+   `handle_stroke_caps`, `render_inner_stroke`, `render_overlay_emoji`.
+   Whatever is still duplicated is the remaining drift surface.
+
+### Not yet done — full unification
+
+The end goal is for `render_shape` to also implement `ShapeRenderer` (a
+`GpuShapeRenderer` delegating to `fills::render` / `strokes::render` /
+`shadows::*`) and route its leaf rendering through `render_leaf_content`, so
+both paths share order and gating by construction. This is a large refactor of
+the live hot path (tiles, `fast_mode`, surface compositing, tree-level drop
+shadows) and **should be gated by golden PNG-vs-PDF-raster parity tests** — do
+not refactor the live path without that safety net.
+
+## File map
+
+| What | Where |
+|------|-------|
+| Vector entry / PDF | `render/pdf.rs`, `render/vector.rs` |
+| Parity trait | `render/shape_renderer.rs` |
+| Order seam | `render/vector.rs::render_leaf_content` |
+| Live shape render | `render.rs::render_shape` |
+| Surface compositing | `render.rs::draw_shape_surface_stack_into` |
+| Shared stroke geometry / caps | `render/strokes.rs` |
+| Shared text render | `render/text.rs` |

render-wasm/src/main.rs

@@ -928,6 +928,22 @@ pub fn free_gpu_resources() {
     get_render_state().free_gpu_resources();
 }
 
+#[no_mangle]
+#[wasm_error]
+pub extern "C" fn render_shape_pdf(a: u32, b: u32, c: u32, d: u32, scale: f32) -> Result<*mut u8> {
+    let id = uuid_from_u32_quartet(a, b, c, d);
+
+    with_state!(state, {
+        let data = state.render_shape_pdf(&id, scale)?;
+
+        let len = data.len() as u32;
+        let mut buf = Vec::with_capacity(4 + data.len());
+        buf.extend_from_slice(&len.to_le_bytes());
+        buf.extend_from_slice(&data);
+        Ok(mem::write_bytes(buf))
+    })
+}
+
 pub fn main() {
     // Why an empty main?
     // Right now with the target `wasm32-unknown-emscripten` it is not possible

render-wasm/src/render.rs

@@ -6,12 +6,15 @@ pub mod gpu_state;
 pub mod grid_layout;
 mod images;
 mod options;
+pub mod pdf;
 mod shadows;
+pub mod shape_renderer;
 mod strokes;
 mod surfaces;
 pub mod text;
 pub mod text_editor;
 mod ui;
+mod vector;
 
 use skia_safe::{self as skia, Matrix, RRect, Rect};
 use std::borrow::Cow;

render-wasm/src/render/images.rs

@@ -213,6 +213,13 @@ impl ImageStore {
         }
     }
 
+    /// Returns a CPU-backed (non-texture) copy of the image, suitable for
+    /// drawing on Skia's PDF canvas which has no GPU context.
+    pub fn get_cpu_image(&mut self, id: &Uuid) -> Option<Image> {
+        let gpu_image = self.get(id)?.clone();
+        gpu_image.make_non_texture_image(self.context.as_mut())
+    }
+
     fn get_internal(&mut self, id: &Uuid, is_thumbnail: bool) -> Option<&Image> {
         let key = (*id, is_thumbnail);
         // Use entry API to mutate the HashMap in-place if needed

render-wasm/src/render/pdf.rs

@@ -0,0 +1,54 @@
+use skia_safe as skia;
+
+use crate::error::Result;
+use crate::state::ShapesPoolRef;
+use crate::uuid::Uuid;
+
+use super::vector::{self, VectorTarget};
+use super::RenderState;
+
+/// Renders a shape tree to a PDF document and returns the raw PDF bytes.
+///
+/// This is a dedicated vector-PDF render path that draws directly to a Skia
+/// PDF canvas, bypassing the GPU surface system entirely. The result is a
+/// true vector PDF — paths, text and fills are represented as PDF drawing
+/// operations rather than rasterised bitmaps. Effects that are inherently
+/// pixel-based (blur, shadows with blur) are rasterised internally by Skia's
+/// PDF backend.
+pub fn render_to_pdf(
+    shared: &mut RenderState,
+    id: &Uuid,
+    tree: ShapesPoolRef,
+    scale: f32,
+) -> Result<Vec<u8>> {
+    let shape = tree
+        .get(id)
+        .ok_or_else(|| crate::error::Error::CriticalError("Shape not found for PDF".to_string()))?;
+    let bounds = shape.extrect(tree, scale);
+
+    let page_w = bounds.width() * scale;
+    let page_h = bounds.height() * scale;
+
+    let mut pdf_bytes: Vec<u8> = Vec::new();
+
+    let metadata = skia::pdf::Metadata {
+        creator: "Penpot".to_string(),
+        producer: "Penpot (Skia PDF)".to_string(),
+        ..Default::default()
+    };
+
+    let document = skia::pdf::new_document(&mut pdf_bytes, Some(&metadata));
+    let mut on_page = document.begin_page((page_w, page_h), None);
+
+    {
+        let page_canvas = on_page.canvas();
+        page_canvas.scale((scale, scale));
+        page_canvas.translate((-bounds.left(), -bounds.top()));
+        vector::render_tree(shared, page_canvas, id, tree, scale, VectorTarget::Pdf)?;
+    }
+
+    let document = on_page.end_page();
+    document.close();
+
+    Ok(pdf_bytes)
+}

render-wasm/src/render/shape_renderer.rs

@@ -0,0 +1,35 @@
+use crate::error::Result;
+use crate::shapes::{Fill, Shape, Stroke};
+
+/// Trait implemented by canvas-based vector export backends (PDF, and
+/// future SVG).
+///
+/// # Parity contract
+///
+/// This trait is the single declaration of the rendering *capabilities* a leaf
+/// shape can have. Two rules keep vector export from drifting away from the
+/// live (GPU) render:
+///
+/// 1. **New capability → new trait method.** Any new per-shape rendering
+///    feature (a new effect, a new fill/stroke mode, etc.) MUST be added as a
+///    method here, not inline in the GPU `render_shape`. Adding a method
+///    produces a compile error in every backend until handled, so the feature
+///    can never be silently missing from vector export.
+/// 2. **Order lives in one place.** The draw order/gating of these methods is
+///    encoded once in `vector::render_leaf_content` (generic over this trait),
+///    so call-order can't diverge between backends that reuse it.
+///
+/// Shape-*type* coverage is enforced separately by exhaustive `match`es (no
+/// `_ =>` arms) in `vector.rs`, so a new `Type` variant also fails to compile
+/// until handled.
+pub trait ShapeRenderer {
+    fn draw_fills(&mut self, shape: &Shape, fills: &[Fill]) -> Result<()>;
+    fn draw_strokes(&mut self, shape: &Shape, strokes: &[&Stroke]) -> Result<()>;
+    fn draw_drop_shadows(&mut self, shape: &Shape) -> Result<()>;
+    fn draw_fill_inner_shadows(&mut self, shape: &Shape) -> Result<()>;
+    fn draw_stroke_inner_shadows(&mut self, shape: &Shape, stroke: &Stroke) -> Result<()>;
+    fn draw_text(&mut self, shape: &Shape) -> Result<()>;
+    fn draw_svg(&mut self, shape: &Shape) -> Result<()>;
+    fn apply_blur_layer(&mut self, shape: &Shape) -> bool;
+    fn restore_blur_layer(&mut self);
+}

render-wasm/src/render/strokes.rs

@@ -12,7 +12,7 @@ use crate::render::filters::compose_filters;
 use crate::render::{get_dest_rect, get_source_rect};
 
 #[allow(clippy::too_many_arguments)]
-fn draw_stroke_on_rect(
+pub(super) fn draw_stroke_on_rect(
     canvas: &skia::Canvas,
     stroke: &Stroke,
     rect: &Rect,
@@ -97,7 +97,7 @@ fn draw_stroke_on_rect(
 }
 
 #[allow(clippy::too_many_arguments)]
-fn draw_stroke_on_circle(
+pub(super) fn draw_stroke_on_circle(
     canvas: &skia::Canvas,
     stroke: &Stroke,
     rect: &Rect,
@@ -288,7 +288,7 @@ fn handle_stroke_cap(
 }
 
 #[allow(clippy::too_many_arguments)]
-fn handle_stroke_caps(
+pub(super) fn handle_stroke_caps(
     path: &skia::Path,
     stroke: &Stroke,
     canvas: &skia::Canvas,

render-wasm/src/render/text.rs

@@ -1,10 +1,10 @@
-use super::{filters, RenderState, Shape, SurfaceId};
+use super::{filters, RenderState, Shape, SurfaceId, DEFAULT_EMOJI_FONT};
 use crate::{
     error::Result,
     math::Rect,
     shapes::{
-        calculate_text_layout_data, set_paint_fill, ParagraphBuilderGroup, Stroke, StrokeKind,
-        TextContent,
+        calculate_text_layout_data, set_paint_fill, ParagraphBuilderGroup, ParagraphLayout, Stroke,
+        StrokeKind, TextContent,
     },
     utils::{get_fallback_fonts, get_font_collection},
 };
@@ -150,6 +150,62 @@ pub fn render_with_bounds_outset(
     stroke_bounds_outset: f32,
     fill_inset: Option<f32>,
     layer_opacity: Option<f32>,
+) -> Result<()> {
+    render_with_bounds_outset_inner(
+        render_state,
+        canvas,
+        shape,
+        paragraph_builders,
+        surface_id,
+        shadow,
+        blur,
+        stroke_bounds_outset,
+        fill_inset,
+        layer_opacity,
+        false,
+    )
+}
+
+/// Like [`render_with_bounds_outset`] but with emoji bitmap overlay for PDF/vector export.
+#[allow(clippy::too_many_arguments)]
+pub fn render_with_bounds_outset_overlay_emoji(
+    canvas: &Canvas,
+    shape: &Shape,
+    paragraph_builders: &mut [Vec<ParagraphBuilder>],
+    shadow: Option<&Paint>,
+    blur: Option<&ImageFilter>,
+    stroke_bounds_outset: f32,
+    fill_inset: Option<f32>,
+    layer_opacity: Option<f32>,
+) -> Result<()> {
+    render_with_bounds_outset_inner(
+        None,
+        Some(canvas),
+        shape,
+        paragraph_builders,
+        None,
+        shadow,
+        blur,
+        stroke_bounds_outset,
+        fill_inset,
+        layer_opacity,
+        true,
+    )
+}
+
+#[allow(clippy::too_many_arguments)]
+fn render_with_bounds_outset_inner(
+    render_state: Option<&mut RenderState>,
+    canvas: Option<&Canvas>,
+    shape: &Shape,
+    paragraph_builders: &mut [Vec<ParagraphBuilder>],
+    surface_id: Option<SurfaceId>,
+    shadow: Option<&Paint>,
+    blur: Option<&ImageFilter>,
+    stroke_bounds_outset: f32,
+    fill_inset: Option<f32>,
+    layer_opacity: Option<f32>,
+    overlay_emoji: bool,
 ) -> Result<()> {
     if let Some(render_state) = render_state {
         let target_surface = surface_id.unwrap_or(SurfaceId::Fills);
@@ -179,6 +235,7 @@ pub fn render_with_bounds_outset(
                             Some(&blur_filter_clone),
                             fill_inset,
                             layer_opacity,
+                            false,
                         );
                         Ok(())
                     },
@@ -197,6 +254,7 @@ pub fn render_with_bounds_outset(
             blur,
             fill_inset,
             layer_opacity,
+            false,
         );
         return Ok(());
     }
@@ -210,6 +268,7 @@ pub fn render_with_bounds_outset(
             blur,
             fill_inset,
             layer_opacity,
+            overlay_emoji,
         );
     }
     Ok(())
@@ -241,6 +300,30 @@ pub fn render(
     )
 }
 
+/// Like [`render`] but rasterizes color emoji as bitmap overlays for PDF/vector export.
+#[allow(clippy::too_many_arguments)]
+pub fn render_overlay_emoji(
+    canvas: &Canvas,
+    shape: &Shape,
+    paragraph_builders: &mut [Vec<ParagraphBuilder>],
+    shadow: Option<&Paint>,
+    blur: Option<&ImageFilter>,
+    fill_inset: Option<f32>,
+    layer_opacity: Option<f32>,
+) -> Result<()> {
+    render_with_bounds_outset_overlay_emoji(
+        canvas,
+        shape,
+        paragraph_builders,
+        shadow,
+        blur,
+        0.0,
+        fill_inset,
+        layer_opacity,
+    )
+}
+
+#[allow(clippy::too_many_arguments)]
 fn render_text_on_canvas(
     canvas: &Canvas,
     shape: &Shape,
@@ -249,6 +332,7 @@ fn render_text_on_canvas(
     blur: Option<&ImageFilter>,
     fill_inset: Option<f32>,
     layer_opacity: Option<f32>,
+    overlay_emoji: bool,
 ) {
     if let Some(blur_filter) = blur {
         let mut blur_paint = Paint::default();
@@ -260,7 +344,13 @@ fn render_text_on_canvas(
     if let Some(shadow_paint) = shadow {
         let layer_rec = SaveLayerRec::default().paint(shadow_paint);
         canvas.save_layer(&layer_rec);
-        draw_text(canvas, shape, paragraph_builders, layer_opacity);
+        draw_text(
+            canvas,
+            shape,
+            paragraph_builders,
+            layer_opacity,
+            overlay_emoji,
+        );
         canvas.restore();
     } else if let Some(eps) = fill_inset.filter(|&e| e > 0.0) {
         if let Some(erode) = skia_safe::image_filters::erode((eps, eps), None, None) {
@@ -268,13 +358,31 @@ fn render_text_on_canvas(
             layer_paint.set_image_filter(erode);
             let layer_rec = SaveLayerRec::default().paint(&layer_paint);
             canvas.save_layer(&layer_rec);
-            draw_text(canvas, shape, paragraph_builders, layer_opacity);
+            draw_text(
+                canvas,
+                shape,
+                paragraph_builders,
+                layer_opacity,
+                overlay_emoji,
+            );
             canvas.restore();
         } else {
-            draw_text(canvas, shape, paragraph_builders, layer_opacity);
+            draw_text(
+                canvas,
+                shape,
+                paragraph_builders,
+                layer_opacity,
+                overlay_emoji,
+            );
         }
     } else {
-        draw_text(canvas, shape, paragraph_builders, layer_opacity);
+        draw_text(
+            canvas,
+            shape,
+            paragraph_builders,
+            layer_opacity,
+            overlay_emoji,
+        );
     }
 
     if blur.is_some() {
@@ -289,6 +397,15 @@ fn paint_text(
     canvas: &Canvas,
     shape: &Shape,
     paragraph_builder_groups: &mut [Vec<ParagraphBuilder>],
+) {
+    paint_text_with_emoji_overlay(canvas, shape, paragraph_builder_groups, false);
+}
+
+fn paint_text_with_emoji_overlay(
+    canvas: &Canvas,
+    shape: &Shape,
+    paragraph_builder_groups: &mut [Vec<ParagraphBuilder>],
+    overlay_emoji: bool,
 ) {
     let text_content = shape.get_text_content();
     let layout_info =
@@ -296,6 +413,11 @@ fn paint_text(
 
     for para in &layout_info.paragraphs {
         para.paragraph.paint(canvas, (para.x, para.y));
+
+        if overlay_emoji {
+            paint_emoji_overlay(canvas, para);
+        }
+
         for deco in &para.decorations {
             draw_text_decorations(
                 canvas,
@@ -309,11 +431,138 @@ fn paint_text(
     }
 }
 
+/// Detects emoji runs in a laid-out paragraph and rasterizes them as bitmap
+/// overlays on the canvas.  Skia's PDF backend cannot render color emoji
+/// glyphs (COLR/CBDT), so we render them to a small raster surface and draw
+/// the resulting image at the correct position.  The regular `paragraph.paint()`
+/// already wrote invisible/placeholder glyphs, keeping the text selectable
+/// in the PDF.
+fn paint_emoji_overlay(canvas: &Canvas, para: &ParagraphLayout) {
+    let line_metrics = para.paragraph.get_line_metrics();
+
+    // The bundled Noto Color Emoji is a vector color font (COLR/CPAL), so emoji
+    // rasterize crisply at any resolution. Skia's PDF backend can't embed those
+    // color tables, so we rasterize each emoji to an image overlay — rendered at
+    // a high effective DPI relative to its final on-page size so it stays sharp
+    // when the PDF is viewed or printed.
+    //
+    // PDF user space is 72 units per inch, so the design→raster scale that yields
+    // TARGET_DPI is output_scale * TARGET_DPI / PDF_POINTS_PER_INCH, where
+    // output_scale is the canvas CTM scale (export scale + any shape transform).
+    // The shape's font size is already folded in via the emoji rect (w/h) below.
+    // Capped by MAX_RASTER_PX so a huge font size can't allocate an unbounded
+    // surface.
+    const TARGET_DPI: f32 = 600.0;
+    const PDF_POINTS_PER_INCH: f32 = 72.0;
+    const MAX_RASTER_PX: f32 = 2048.0;
+
+    let ctm = canvas.local_to_device_as_3x3();
+    let sx = (ctm.scale_x().powi(2) + ctm.skew_y().powi(2)).sqrt();
+    let sy = (ctm.skew_x().powi(2) + ctm.scale_y().powi(2)).sqrt();
+    let output_scale = sx.max(sy).max(1.0);
+
+    for line in &line_metrics {
+        let style_runs = line.get_style_metrics(line.start_index..line.end_index);
+
+        // Build a list of (start, end, is_emoji) for each style run.
+        let mut run_info: Vec<(usize, usize, bool)> = Vec::new();
+        for (i, (start_idx, _style_metric)) in style_runs.iter().enumerate() {
+            let end_idx = style_runs.get(i + 1).map_or(line.end_index, |next| next.0);
+            if *start_idx >= end_idx {
+                continue;
+            }
+
+            let font = para.paragraph.get_font_at(*start_idx);
+            let family_name = font.typeface().family_name();
+
+            let normalized = family_name.to_lowercase().replace(' ', "-");
+            let is_emoji = normalized.contains(DEFAULT_EMOJI_FONT);
+            run_info.push((*start_idx, end_idx, is_emoji));
+        }
+
+        // Merge consecutive emoji runs into contiguous ranges.
+        // ZWJ emoji sequences (e.g. 👩🏿‍🚀) may be split into multiple
+        // style runs by Skia — one per codepoint — but the composed glyph
+        // is a single indivisible cluster.  Querying `get_rects_for_range`
+        // on a partial cluster returns empty results, so we must use the
+        // full cluster range.
+        let mut merged_emoji_ranges: Vec<(usize, usize)> = Vec::new();
+        for &(start, end, is_emoji) in &run_info {
+            if is_emoji {
+                if let Some(last) = merged_emoji_ranges.last_mut() {
+                    if last.1 == start {
+                        // Extend the previous range
+                        last.1 = end;
+                        continue;
+                    }
+                }
+                merged_emoji_ranges.push((start, end));
+            }
+        }
+
+        for (range_start, range_end) in &merged_emoji_ranges {
+            // Get the bounding rects for this (possibly merged) emoji run
+            let rects = para.paragraph.get_rects_for_range(
+                *range_start..*range_end,
+                skia::textlayout::RectHeightStyle::Tight,
+                skia::textlayout::RectWidthStyle::Tight,
+            );
+
+            for text_box in &rects {
+                let r = &text_box.rect;
+                let w = r.width();
+                let h = r.height();
+                if w <= 0.0 || h <= 0.0 {
+                    continue;
+                }
+
+                // Render at TARGET_DPI relative to the emoji's final on-page
+                // size, clamped so the surface stays within MAX_RASTER_PX.
+                let mut raster_scale = output_scale * (TARGET_DPI / PDF_POINTS_PER_INCH);
+                let max_dim = w.max(h) * raster_scale;
+                if max_dim > MAX_RASTER_PX {
+                    raster_scale *= MAX_RASTER_PX / max_dim;
+                }
+                let raster_w = (w * raster_scale).ceil() as i32;
+                let raster_h = (h * raster_scale).ceil() as i32;
+
+                let info = skia::ImageInfo::new_n32_premul((raster_w, raster_h), None);
+                let Some(mut raster) = skia::surfaces::raster(&info, None, None) else {
+                    continue;
+                };
+
+                let rc = raster.canvas();
+                rc.clear(skia::Color::TRANSPARENT);
+                rc.scale((raster_scale, raster_scale));
+                // Translate so the emoji rect origin maps to (0,0)
+                rc.translate((-r.left, -r.top));
+                para.paragraph.paint(rc, (0.0, 0.0));
+
+                let image = raster.image_snapshot();
+
+                // Draw the rasterized emoji onto the PDF canvas at the
+                // correct position (paragraph offset + emoji rect origin).
+                let dest = skia::Rect::from_xywh(para.x + r.left, para.y + r.top, w, h);
+
+                let sampling = skia::SamplingOptions::from(skia::CubicResampler::mitchell());
+                canvas.draw_image_rect_with_sampling_options(
+                    &image,
+                    None,
+                    dest,
+                    sampling,
+                    &Paint::default(),
+                );
+            }
+        }
+    }
+}
+
 fn draw_text(
     canvas: &Canvas,
     shape: &Shape,
     paragraph_builder_groups: &mut [Vec<ParagraphBuilder>],
     layer_opacity: Option<f32>,
+    overlay_emoji: bool,
 ) {
     if let Some(opacity) = layer_opacity {
         let mut opacity_paint = Paint::default();
@@ -324,7 +573,7 @@ fn draw_text(
         canvas.save_layer(&SaveLayerRec::default());
     }
 
-    paint_text(canvas, shape, paragraph_builder_groups);
+    paint_text_with_emoji_overlay(canvas, shape, paragraph_builder_groups, overlay_emoji);
 }
 
 /// Renders an inner stroke using mask + SrcIn + DstOver layer structure.

render-wasm/src/shapes.rs

@@ -1077,6 +1077,17 @@ impl Shape {
         self.selrect.center()
     }
 
+    /// Returns the shape's transform matrix centered around its selrect center,
+    /// so that rotations and scales happen around the shape's visual center
+    /// rather than the origin.
+    pub fn centered_transform(&self) -> Matrix {
+        let center = self.center();
+        let mut matrix = self.transform;
+        matrix.post_translate(center);
+        matrix.pre_translate(-center);
+        matrix
+    }
+
     pub fn clip(&self) -> bool {
         self.clip_content
     }

render-wasm/src/state.rs

@@ -82,6 +82,10 @@ impl State {
         get_render_state().render_shape_pixels(id, &self.shapes, scale, timestamp)
     }
 
+    pub fn render_shape_pdf(&mut self, id: &Uuid, scale: f32) -> Result<Vec<u8>> {
+        crate::render::pdf::render_to_pdf(get_render_state(), id, &self.shapes, scale)
+    }
+
     pub fn start_render_loop(&mut self, timestamp: i32) -> Result<FrameType> {
         let render_state = get_render_state();
         // If zoom changed (e.g. interrupted zoom render followed by pan), the