Effects: Effect › Rasterize draws an object as pixels while its paths stay editable

The Effect menu had no Rasterize. Object › Rasterize replaces the
object with an image, so its paths can no longer be edited.

Effect › Rasterize… (`rasterize`) is a live effect with Object ›
Rasterize's options: color model, resolution (the document's raster
effects resolution by default), white or transparent background,
anti-aliasing, Create Clipping Mask and Add Around Object. The canvas
draws the object as square pixels over its bounds, and its paths, type
and other art stay as they are. The effects above it in the stack,
shadows included, are part of its image, and shadows below it are cast
by the image. When Rasterize is an object's only raster effect, Expand
Appearance and PDF and SVG export give the image Object › Rasterize
gives with the same options.

Object › Rasterize now measures the art as drawn, with its geometry
effects, brush art and raster effects, so a Transform effect that moves
the art no longer leaves the image empty. Its Create Clipping Mask
clips the image to the art as drawn. The canvas no longer panics
drawing a pixel effect such as Gaussian Blur on an object about 65,500
screen pixels wide: the raster of such an object is at most 32,768
pixels a side, and the object is drawn into it at a lower resolution.

Docs: docs/mcp.md, docs/effects-parity.md, docs/target-app-parity.md,
ROADMAP.

crates/engine/src/cmd/rasterfx.rs

@@ -6,11 +6,13 @@
 //! model, background, anti-aliasing, room around the art). Shadows and outer glows only add the
 //! effect: the image (with the object's own area knocked out) goes under the untouched vector
 //! object. Effects that change the object itself (inner glow, feather, Gaussian blur) replace it
-//! with the image. Expand Appearance makes its images with the same helpers.
+//! with the image. An object whose only raster effect is a Rasterize of its own is replaced with
+//! the image Object › Rasterize makes with that effect's options. Expand Appearance makes its
+//! images with the same helpers.
 //!
 //! SVG has filters for shadows, glows, blurs and feathers but none for the Photoshop-style
-//! effects (Radial Blur, Unsharp Mask…): SVG export turns only the objects carrying one of those
-//! into images the same way ([`flatten_pixel_effects`]).
+//! effects (Radial Blur, Unsharp Mask…) or Rasterize: SVG export turns only the objects carrying
+//! one of those into images the same way ([`flatten_pixel_effects`]).
 
 use std::sync::Arc;
 
@@ -273,11 +275,15 @@ fn below_images(d: &mut Document, n: &Node) -> Option<Vec<Node>> {
 }
 
 /// The raster effects of `n` (its own, its fills' and strokes') as an embedded image of `d`
-/// rendered at the document's raster effects resolution, without `n`'s transparency (that stays
-/// on the object). With `below` (they all paint below it: shadows and outer glows) the image holds
-/// just them; with `members` too, a group's or layer's image leaves out its members' raster
-/// effects (they get images of their own).
+/// rendered at the document's raster effects resolution, or at a Rasterize effect's finer one (an
+/// object whose only raster effect is its own Rasterize gets [`rasterize_effect_image`]'s image),
+/// without `n`'s transparency (that stays on the object). With `below` (they all paint below it:
+/// shadows and outer glows) the image holds just them; with `members` too, a group's or layer's
+/// image leaves out its members' raster effects (they get images of their own).
 pub(crate) fn raster_image(d: &mut Document, n: &Node, below: bool, members: bool) -> Option<Node> {
+    if !below && let Some(image) = rasterize_effect_image(d, n) {
+        return Some(image);
+    }
     let mut whole = n.clone();
     (whole.opacity, whole.blend) = (1.0, Default::default());
     whole.extras_mut().mask = None;
@@ -291,10 +297,37 @@ pub(crate) fn raster_image(d: &mut Document, n: &Node, below: bool, members: boo
         strip_raster(&mut b, false);
         b
     });
-    let scale = effects_scale(d);
+    // A Rasterize effect at a finer resolution than the document's is rendered at its own.
+    let scale = raster_fx(n)
+        .iter()
+        .filter_map(|fx| if let RasterFx::Rasterize(r) = fx { r.ppi } else { None })
+        .fold(effects_scale(d), |s, ppi| s.max(ppi / 72.0));
     effect_image(d, &whole, bare.as_ref(), scale)
 }
 
+/// The image Object › Rasterize makes of `n` with the options of `n`'s Effect › Rasterize, when
+/// that is its only visible raster effect and is its own (not a fill's or a stroke's): made of `n`
+/// without that effect and without its transparency, which stays on the object. `None` otherwise,
+/// or when the image can't be made.
+fn rasterize_effect_image(d: &mut Document, n: &Node) -> Option<Node> {
+    let [RasterFx::Rasterize(r)] = raster_fx(n)[..] else { return None };
+    let at = n.appearance.effects.iter().position(|e| e.visible && e.id == effects::RASTERIZE)?;
+    let p = json!({
+        "ppi": r.ppi.unwrap_or(d.raster_effects_ppi),
+        "colorModel": r.color_model.id(),
+        "background": if r.white { "white" } else { "transparent" },
+        "antiAlias": if !r.anti_alias { "none" } else if r.hinted { "type" } else { "art" },
+        "clippingMask": r.clipping_mask,
+        "addAround": r.add_around,
+    });
+    let mut whole = n.clone();
+    whole.appearance.effects.remove(at);
+    (whole.opacity, whole.blend) = (1.0, Default::default());
+    whole.extras_mut().mask = None;
+    let image = super::menucmds::rasterize_art(d, vec![whole], &p, "object.rasterize").ok()?;
+    Some(image.into_node(d))
+}
+
 /// `v` (an object without its raster effects) replaced by `image` of the object with them: the
 /// image takes its place with its id, name and transparency (a layer keeps the image as its only
 /// member).
@@ -393,7 +426,8 @@ fn placed_symbol(d: &Document, n: &Node) -> Option<Node> {
 enum Which {
     /// Every raster effect (PDF).
     All,
-    /// Objects with a Photoshop-style effect, which SVG can't draw (with all their raster effects).
+    /// Objects with a Photoshop-style effect or Rasterize, which SVG can't draw (with all their
+    /// raster effects).
     Pixel,
 }
 
@@ -402,7 +436,7 @@ fn imaged(n: &Node, which: Which) -> bool {
     let fx = raster_fx(n);
     match which {
         Which::All => !fx.is_empty(),
-        Which::Pixel => fx.iter().any(|f| matches!(f, RasterFx::Pixel(_))),
+        Which::Pixel => fx.iter().any(|f| matches!(f, RasterFx::Pixel(_) | RasterFx::Rasterize(_))),
     }
 }
 
@@ -499,8 +533,8 @@ pub fn flatten_raster_effects(doc: &Document) -> Option<Document> {
 }
 
 /// A copy of `doc` in which the objects with Photoshop-style raster effects (Radial Blur, Unsharp
-/// Mask…) are images as [`flatten_raster_effects`] makes them (SVG export: its filters draw the
-/// other raster effects live), or `None` when there are none.
+/// Mask…) or Rasterize are images as [`flatten_raster_effects`] makes them (SVG export: its
+/// filters draw the other raster effects live), or `None` when there are none.
 pub fn flatten_pixel_effects(doc: &Document) -> Option<Document> {
     flatten(doc, &mut FlattenReport::new(Which::Pixel, doc))
 }