#1388: retain whole text raster for animator blur

crates/render/src/pipeline.rs

@@ -488,7 +488,7 @@ impl<'a> Renderer<'a> {
             || styles::active(ctx, layer)
             || ctx.comp.layers.iter().any(|l| matches!(l.source, LayerSource::Light { .. }))
             || self.is_adv3d(ctx)
-            || (matches!(layer.source, LayerSource::Text) && text::per_char_3d(ctx, layer))
+            || (matches!(layer.source, LayerSource::Text) && (text::per_char_3d(ctx, layer) || text::animator_blur(ctx, layer)))
         {
             return None;
         }

crates/render/src/tests/raster_clip.rs

@@ -332,3 +332,29 @@ fn fine_clip_cells_have_distinct_cache_keys() {
     assert_ne!(key(a), key(kurbo::Rect::ZERO));
     assert_ne!(key(b), key(kurbo::Rect::ZERO));
 }
+
+/// Text animator Blur reads beyond the fixed anti-aliasing padding of a clipped window.
+#[test]
+fn animated_text_blur_keeps_offscreen_glyph_pixels_while_panning() {
+    let (mut p, cid) = scene(|p, c| text3(p, c, [W as f64 / 2.0, H as f64 / 2.0, -zoom() + 40.0], 0.0));
+    let mut next = p.next_id;
+    let mut ids = Ids(&mut next);
+    let props = build::text_anim_props(&mut ids, "blur", false);
+    let mut animator = build::text_animator(&mut ids, "Blur", props);
+    animator.prop_mut("properties/blur").unwrap().value = Value::Vec2([40.0, 40.0]);
+    p.next_id = next;
+    p.comp_mut(cid).unwrap().layers[0].props.group_mut("text/animators").unwrap().children.push(animator.into());
+    let opts = RenderOpts { scale: 0.125, ..Default::default() };
+    let cache = crate::LayerCache::default();
+    for dx in [-10.0, 0.0, 10.0] {
+        set(&mut p.comp_mut(cid).unwrap().layers[0], "transform/position", Value::Vec3([W as f64 / 2.0 + dx, H as f64 / 2.0, -zoom() + 40.0]));
+        let mut r = Renderer::new(&p, &NoFootage, opts);
+        r.cache = Some(&cache);
+        let ctx = r.eval_ctx(cid, Tick::ZERO).unwrap();
+        let layer = &p.comp(cid).unwrap().layers[0];
+        assert!(r.raster_clip(&ctx, layer).is_none(), "animator blur needs off-window pixels");
+        let mut whole = Renderer::new(&p, &NoFootage, opts);
+        whole.whole_raster = true;
+        assert_eq!(r.comp_frame(cid, Tick::ZERO).data, whole.comp_frame(cid, Tick::ZERO).data);
+    }
+}

crates/render/src/text.rs

@@ -509,6 +509,16 @@ pub fn per_char_3d(ctx: &EvalCtx, layer: &Layer) -> bool {
     layer.is_3d() && layer.props.sub("text").is_some_and(|t| ctx.b(layer, t, "perChar3d"))
 }
 
+/// Animator blur can read glyph pixels beyond a viewport raster window. Conservatively
+/// keep the whole raster even when the current selector happens to select no characters.
+pub(crate) fn animator_blur(ctx: &EvalCtx, layer: &Layer) -> bool {
+    layer.props.group("text/animators").is_some_and(|anims| {
+        anims.groups().filter(|anim| anim.enabled).any(|anim| {
+            anim.sub("properties").and_then(|props| props.get("blur")).is_some_and(|blur| ctx.value(layer, blur).as_vec2().iter().any(|value| *value != 0.0))
+        })
+    })
+}
+
 /// One drawn character.
 #[derive(Clone, Debug)]
 pub struct PlacedGlyph {