Fix #1723: a pattern's tile is drawn again when what its art shows changes

A tile was kept while the pattern's own art, tile and tiling were the ones it
was drawn from. Art that shows a symbol, is painted with another pattern or
holds an image or type doesn't change when those do, so the pattern kept
drawing the old symbol (in every renderer on the thread: the tiles are
shared). Such a tile now also remembers the document's pattern and symbol
art, image pixels and fonts, and is drawn again when they differ. A raster
effect on an object painted with a pattern reads all of that too, as one on
a symbol instance does.

crates/render/src/fx.rs

@@ -532,7 +532,8 @@ impl Drawn {
 /// objects in it ([`Reads::of`]): which parts of [`Inputs`] can change what its rasters show.
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
 pub(crate) struct Reads {
-    /// Pattern paints: the pattern definitions.
+    /// Pattern paints: the pattern definitions. Their art can hold anything, so content painted
+    /// with a pattern reads everything else too.
     patterns: bool,
     /// Symbol instances and type with inline graphics: the symbols' art. Symbol art can hold
     /// anything, so content that shows a symbol reads everything else too.
@@ -550,14 +551,25 @@ pub(crate) struct Reads {
 impl Reads {
     /// What the content of `n` reads.
     pub(crate) fn of(n: &Node) -> Self {
+        Self::of_all(std::iter::once(n))
+    }
+
+    /// What the content of `nodes` reads together. A pattern's art can hold anything, as a
+    /// symbol's can, so content painted with a pattern reads everything else too (#1723).
+    pub(crate) fn of_all<'a>(nodes: impl Iterator<Item = &'a Node>) -> Self {
         let mut reads = Self::default();
-        reads.add(n);
-        if reads.symbols {
+        nodes.for_each(|n| reads.add(n));
+        if reads.symbols || reads.patterns {
             return Self { patterns: true, symbols: true, images: true, brushes: true, text: true };
         }
         reads
     }
 
+    /// Does the content read anything outside its own nodes?
+    pub(crate) fn any(self) -> bool {
+        self != Self::default()
+    }
+
     fn add(&mut self, n: &Node) {
         let pattern = |p: &vectorcraft_color::Paint| matches!(p, vectorcraft_color::Paint::Pattern { .. });
         n.walk(&mut |c| {

crates/render/src/pattern.rs

@@ -6,14 +6,16 @@
 //! with the paint transform mapping pixels → pattern space → document. Tiles are cached per
 //! pattern name and raster scale (and ink plane, see [`crate::ink`]) within
 //! [`lru::PATTERN_BUDGET`]. A tile is used while the pattern's definition is the one it was
-//! rasterized from (art `Arc` identity, tile, tile type, overlap): the pattern's "revision".
+//! rasterized from (art `Arc` identity, tile, tile type, overlap): the pattern's "revision", and,
+//! when its art shows more than itself (a symbol, another pattern, an image, type), while what
+//! the document holds of those is what it held then ([`Deps`]).
 //!
 //! Pattern editing mode (`Document::pattern_edit`) draws only the temporary tile layer, with
 //! dimmed copies of it at the neighbouring tile positions and the tile edge.
 
 use std::cell::RefCell;
 use std::hash::{Hash, Hasher};
-use std::sync::Arc;
+use std::sync::{Arc, Weak};
 
 use vectorcraft_doc::pattern::{Overlap, PatternDef, TileType};
 use vectorcraft_doc::{Document, Node};
@@ -32,8 +34,46 @@ const MAX_TILE_PX: f64 = 2048.0;
 /// ([`raster_scale`]).
 type TileKey = (String, u64);
 
+/// What a tile was drawn from besides its pattern's own art, for art that shows more than itself:
+/// the art of every pattern and symbol and the pixels of every image in the document, and the
+/// fonts. Editing a symbol leaves the art of a pattern that shows it as it was, so the art alone
+/// kept the tile from before (#1723). Held weakly: a weak reference keeps the allocation, so no
+/// other value gets one of these addresses while the tile is kept.
+struct Deps {
+    art: Vec<Weak<Node>>,
+    pixels: Vec<Weak<Vec<u8>>>,
+    fonts: u64,
+}
+
+impl Deps {
+    fn art(doc: &Document) -> impl Iterator<Item = &Arc<Node>> {
+        doc.patterns.iter().flat_map(|p| &p.art).chain(doc.symbols.iter().map(|s| &s.art))
+    }
+
+    fn pixels(doc: &Document) -> impl Iterator<Item = &Arc<Vec<u8>>> {
+        doc.images.values().flat_map(|b| std::iter::once(&b.bytes).chain(&b.proxy))
+    }
+
+    fn of(doc: &Document) -> Self {
+        Self {
+            art: Self::art(doc).map(Arc::downgrade).collect(),
+            pixels: Self::pixels(doc).map(Arc::downgrade).collect(),
+            fonts: vectorcraft_text::FontDb::global().generation(),
+        }
+    }
+
+    /// Does `doc` hold what the tile was drawn from?
+    fn current(&self, doc: &Document) -> bool {
+        self.fonts == vectorcraft_text::FontDb::global().generation()
+            && self.art.iter().map(Weak::as_ptr).eq(Self::art(doc).map(Arc::as_ptr))
+            && self.pixels.iter().map(Weak::as_ptr).eq(Self::pixels(doc).map(Arc::as_ptr))
+    }
+}
+
 struct TileEntry {
     art: Vec<Arc<Node>>,
+    /// `None` for art that shows only itself.
+    deps: Option<Deps>,
     params: (Rect, TileType, Overlap),
     sx: f64,
     sy: f64,
@@ -163,7 +203,10 @@ pub(crate) fn set_pattern_paint(ctx: &mut RenderContext, name: &str, xf: Affine,
         let mut c = c.borrow_mut();
         let tiles = &mut c.tiles[ink as usize];
         let t = tiles.tick();
-        tiles.get(&key, t).filter(|e| e.params == params && same_art(&e.art, &def.art)).map(|e| (e.pixmap.clone(), e.sx, e.sy))
+        tiles
+            .get(&key, t)
+            .filter(|e| e.params == params && same_art(&e.art, &def.art) && e.deps.as_ref().is_none_or(|d| d.current(doc)))
+            .map(|e| (e.pixmap.clone(), e.sx, e.sy))
     });
     let (pm, sx, sy) = match hit {
         Some(h) => h,
@@ -176,11 +219,12 @@ pub(crate) fn set_pattern_paint(ctx: &mut RenderContext, name: &str, xf: Affine,
             };
             let pm = Arc::new(pm);
             let (sx, sy) = (w as f64 / pw, h as f64 / ph);
+            let deps = crate::fx::Reads::of_all(def.art.iter().map(|a| &**a)).any().then(|| Deps::of(doc));
             CACHE.with(|c| {
                 let mut c = c.borrow_mut();
                 let tiles = &mut c.tiles[ink as usize];
                 let (t, bytes) = (tiles.tick(), size_of::<TileEntry>() + w as usize * h as usize * 4);
-                tiles.insert(key, TileEntry { art: def.art.clone(), params, sx, sy, pixmap: pm.clone() }, bytes, t);
+                tiles.insert(key, TileEntry { art: def.art.clone(), deps, params, sx, sy, pixmap: pm.clone() }, bytes, t);
             });
             (pm, sx, sy)
         }

crates/render/src/tests_memory.rs

@@ -940,6 +940,49 @@ fn rasters_draw_pattern_edits() {
     });
 }
 
+/// #1723: a pattern's tile is drawn again when what its art shows changes while the art itself
+/// doesn't: a symbol an instance in it shows, or another pattern it is painted with. So is a
+/// raster effect on an object painted with such a pattern.
+#[test]
+fn pattern_tiles_draw_edits_to_what_their_art_shows() {
+    let _fonts = fonts_steady();
+    use vectorcraft_doc::pattern::{PatternDef, pattern_paint};
+    use vectorcraft_geom::shapes::rectangle;
+    let tile = |name: &str, art: Node| {
+        let mut def = PatternDef::new(name, vec![Arc::new(art)]);
+        def.tile = Rect::new(0.0, 0.0, 20.0, 20.0);
+        def
+    };
+    // Pattern `Stamps` shows symbol `S`; pattern `Outer` is a square painted with pattern `Checks`.
+    let doc = |pattern: &str, effects: Vec<vectorcraft_doc::Effect>| {
+        let mut d = Document::new(200.0, 100.0);
+        let art = symbol_art(&mut d);
+        d.symbols.push(vectorcraft_doc::Symbol { name: "S".into(), art: Arc::new(art) });
+        let shown = Node::new(d.alloc_id(), NodeKind::SymbolInstance { symbol: "S".into(), xf: Affine::translate((10.0, 10.0)) });
+        d.patterns.push(tile("Stamps", shown));
+        d.patterns.push(checks(Color::rgb(1.0, 0.0, 0.0)));
+        let square = filled(&mut d, rectangle(Rect::new(0.0, 0.0, 20.0, 20.0)), pattern_paint("Checks"), vec![]);
+        d.patterns.push(tile("Outer", square));
+        let painted = filled(&mut d, rectangle(Rect::new(10.0, 10.0, 190.0, 90.0)), pattern_paint(pattern), effects);
+        with_art(d, vec![painted])
+    };
+    let new_symbol = |d: &mut Document| {
+        let red = vectorcraft_doc::Appearance::basic(Paint::solid(Color::rgb(1.0, 0.0, 0.0)), Paint::None, 0.0);
+        let bar = Node::path(d.alloc_id(), rectangle(Rect::new(-8.0, -2.0, 8.0, 2.0)), red);
+        d.symbols[0].art = Arc::new(bar);
+    };
+    let new_checks = |d: &mut Document| {
+        if let Some(def) = d.pattern_mut("Checks") {
+            def.art = checks(Color::rgb(0.0, 0.0, 1.0)).art;
+        }
+    };
+    let blur = || vec![effect("blur.gaussian", serde_json::json!({"radius": 2.0}))];
+    edit_draws_as_new(doc("Stamps", vec![]), new_symbol);
+    edit_draws_as_new(doc("Stamps", blur()), new_symbol);
+    edit_draws_as_new(doc("Outer", vec![]), new_checks);
+    edit_draws_as_new(doc("Outer", blur()), new_checks);
+}
+
 /// Raster effects are made again when a symbol shown inside another symbol changes (a group's drop
 /// shadow around an instance of the other symbol), when a brush definition changes (a brushed
 /// stroke's drop shadow), and when an image's pixels change under the same key, as when a linked