websem: admit SVG pattern context and filter composition

crates/n0_cli/README.md

@@ -539,8 +539,8 @@ cargo run -p n0_cli --bin n0 -- \
   The filter estate contains 26 chassis/blur cells, 60 shadow-graph, 28 native
   drop-shadow, 27 color-matrix, 32 component-transfer, 38 blend, 37 morphology,
   91 turbulence/displacement, 41 convolution-rung, and 71 diffuse-lighting
-  cells. The complete corpus contains 874 Chromium-baked cells plus 10 sampled
-  frames, with 170 named
+  cells. The complete corpus contains 936 Chromium-baked cells plus 10 sampled
+  frames, with 169 named
   refusal rows. `feFlood`, `feComposite`,
   `feMerge`, `feMergeNode`, `feDropShadow`, `feColorMatrix`,
   `feComponentTransfer`, `feBlend`, `feMorphology`, `feConvolveMatrix`,
@@ -787,22 +787,35 @@ cargo run -p n0_cli --bin n0 -- \
   `patternTransform` is the transform property's presentation hint: CSS beats
   it and a plain `transform` attribute is inert. Translation, axis scale,
   reflection, and exact quarter turns are admitted. The repeating source can
-  contain admitted rectangles, gradients, `<use>`, masks, and a pattern nested
-  alone; pattern paint covers admitted rect, ellipse, and path fills and
-  strokes, and target opacity, clip, mask, and filter scopes retain their
-  established order. Sixty-two Chromium-baked cells cover that profile,
+  contain admitted rectangles, gradients, `<use>`, masks, filters, and a
+  pattern nested alone; a filter may wrap that sole nested-pattern draw.
+  Pattern paint covers admitted rect, ellipse, and path fills and strokes, and
+  target opacity, clip, mask, and filter scopes retain their established
+  order. A pattern may be selected through all four destination
+  fill/stroke × context-fill/context-stroke crossings, including CSS ingress,
+  recursive `<use>` owners, object-box coordinates, transforms, opacity,
+  fallback/nothing semantics, masks, and filters. It may also supply a
+  source-derived filter's input when the filtered source is one direct
+  sharp-cornered rectangle with exactly one pattern-painted fill or simple
+  stroke channel. That filter profile includes transparent and alpha-bearing
+  tiles, gradients, masks, strokes, and nested patterns. One hundred
+  twenty-four Chromium-baked cells cover the core and composition profiles,
   including independent object-box clients and one inline-HTML SVG entry; all
   are exact without a new tolerance.
-  What refuses by stable name: a pattern selected through
-  `context-fill`/`context-stroke`; an external template dependency; a non-`px`
+  What refuses by stable name: an external template dependency; a non-`px`
   unit, CSS math, `var()`, CSS-wide tile value, or CSS comments around an
   otherwise valid tile length; a source child outside the admitted element
-  slice; filter composition inside the source program; curved source
-  coverage; isolated multi-draw source
+  slice; curved source coverage; isolated multi-draw source
   opacity or a geometric source clip; another source draw mixed with a nested
   pattern; a fractional final tile extent; and a final tile map carrying a
-  general rotation or shear. Those last five are measured picture-shader
-  precision boundaries, not guessed omissions. Before its patrol, the valid
+  general rotation or shear. A source-derived filter over curved, rounded,
+  multi-draw, or wider pattern-painted target geometry has its own
+  filtered-pattern coverage refusal. The context-aware source classifier also
+  keeps eventual gradients behind the existing color-matrix, component-
+  transfer, convolution, morphology, native-shadow, and translucent-source
+  precision names instead of letting a context keyword hide them. Those
+  picture-shader and source-layer boundaries are measured, not guessed
+  omissions. Before its patrol, the valid
   comment spelling silently selected fallback in both admissions and changed
   all 2,304 target pixels at maximum delta 202. A derived template whose
   author stylesheet may contribute `transform:none` also refuses because the

crates/websem/tests/context_paint_contract.rs

@@ -325,13 +325,22 @@ fn nonstandard_context_fallback_refuses_from_every_ingress() {
 }
 
 #[test]
-fn pattern_and_external_urls_keep_their_own_refusal_through_context() {
-    let pattern = refusal(&document(
-        r##"<defs><pattern id="p" width="8" height="8"><rect width="4" height="4" fill="red"/></pattern><rect id="r" width="20" height="20" fill="context-fill"/></defs><use href="#r" fill="url(#p)"/>"##,
+fn pattern_resolves_through_context_while_external_urls_keep_their_refusal() {
+    let pattern = admit_both(&document(
+        r##"<defs><pattern id="p" width=".25" height=".5"><rect width="5" height="10" fill="red"/></pattern><rect id="r" width="20" height="20" fill="context-fill"/></defs><use href="#r" fill="url(#p)"/>"##,
     ));
+    let resolved = pattern.nodes()[0]
+        .paints
+        .pattern()
+        .expect("the context owner selects one source-neutral pattern");
     assert!(
-        matches!(pattern, CompileError::UnsupportedFill(ref reason) if reason.contains("pattern paint selected through context-fill/context-stroke")),
-        "{pattern}"
+        resolved.items().nodes().next().is_some(),
+        "the selected pattern retains its resolved source program"
+    );
+    assert_eq!(
+        (resolved.width(), resolved.height()),
+        (5.0, 10.0),
+        "object-box tile extents use the 20x20 context owner's reference space"
     );
 
     let external = refusal(&document(

crates/websem/tests/filter_contract.rs

@@ -29,24 +29,33 @@ fn document(body: &str) -> String {
     )
 }
 
-fn admit_both(source: &str) -> Frame {
-    let strict = SvgFrameSource::from_standalone_svg(source, viewport()).expect("strict admits");
+fn admit_both_named(source: &str, context: &str) -> Frame {
+    let strict = SvgFrameSource::from_standalone_svg(source, viewport())
+        .unwrap_or_else(|error| panic!("{context}: strict must admit: {error}"));
     let best = SvgFrameSource::from_standalone_svg_best_effort(source, viewport())
-        .expect("best effort admits");
+        .unwrap_or_else(|error| panic!("{context}: best effort must admit: {error}"));
     let declared: Vec<_> = best
         .degradations()
         .iter()
         .filter(|degradation| degradation.action() != DegradationAction::SamplesAsBase)
         .collect();
     assert!(
         declared.is_empty(),
-        "an admitted filter declares nothing: {declared:?}"
+        "{context}: an admitted filter declares nothing: {declared:?}"
     );
     let frame = strict.base_frame();
-    assert_eq!(frame, best.base_frame(), "admissions are frame-identical");
+    assert_eq!(
+        frame,
+        best.base_frame(),
+        "{context}: admissions are frame-identical"
+    );
     frame
 }
 
+fn admit_both(source: &str) -> Frame {
+    admit_both_named(source, "filter source")
+}
+
 fn assert_target_skip(source: &str, reason: &str) {
     let strict =
         SvgFrameSource::from_standalone_svg(source, viewport()).expect_err("strict must refuse");
@@ -1032,6 +1041,167 @@ fn component_transfer_precision_patrols_name_paint_server_and_transform_boundari
     ));
 }
 
+#[test]
+fn direct_rect_patterns_feed_every_admitted_source_dependent_filter_family() {
+    let primitives = [
+        r##"<feGaussianBlur stdDeviation="2"/>"##,
+        r##"<feOffset dx="3" dy="2"/>"##,
+        r##"<feFlood flood-color="#e11d48" result="f"/><feBlend in="SourceGraphic" in2="f" mode="multiply"/>"##,
+        r##"<feOffset dx="3" dy="2" result="o"/><feMerge><feMergeNode in="o"/><feMergeNode in="SourceGraphic"/></feMerge>"##,
+        r##"<feComponentTransfer><feFuncR type="linear" slope=".4" intercept=".1"/><feFuncA type="linear" slope=".7"/></feComponentTransfer>"##,
+        r##"<feMorphology operator="dilate" radius="2"/>"##,
+        r##"<feConvolveMatrix order="3" kernelMatrix="0 -1 0 -1 5 -1 0 -1 0"/>"##,
+        r##"<feDropShadow dx="3" dy="2" stdDeviation="2" flood-color="#0f172a"/>"##,
+        r##"<feColorMatrix type="saturate" values=".2"/>"##,
+        r##"<feFlood flood-color="#e11d48" flood-opacity=".7" result="f"/><feComposite in="SourceGraphic" in2="f" operator="arithmetic" k1=".5" k2=".5" k3=".25" k4=".1"/>"##,
+        r##"<feTurbulence baseFrequency=".08" numOctaves="1" seed="5" result="n"/><feDisplacementMap in="SourceGraphic" in2="n" scale="7"/>"##,
+        r##"<feDiffuseLighting surfaceScale="2" diffuseConstant="1.2" lighting-color="#f8fafc"><feDistantLight azimuth="225" elevation="45"/></feDiffuseLighting>"##,
+    ];
+    for primitive in primitives {
+        admit_both_named(
+            &document(&format!(
+                r##"  <rect width="64" height="64" fill="white"/>
+  <defs>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="8" height="8"><rect width="4" height="8" fill="#16a34a"/><rect x="4" width="4" height="8" fill="#2563eb"/></pattern>
+    <filter id="f" filterUnits="userSpaceOnUse" primitiveUnits="userSpaceOnUse" x="0" y="0" width="64" height="64" color-interpolation-filters="sRGB">{primitive}</filter>
+  </defs>
+  <rect x="10" y="10" width="44" height="44" fill="url(#p)" fill-opacity=".57" filter="url(#f)"/>"##
+            )),
+            primitive,
+        );
+    }
+
+    admit_both(&document(
+        r##"  <rect width="64" height="64" fill="white"/>
+  <defs>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="8" height="8"><rect width="4" height="8" fill="#16a34a"/></pattern>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="64" height="64" color-interpolation-filters="sRGB"><feComponentTransfer><feFuncR type="linear" slope=".4"/></feComponentTransfer></filter>
+    <rect id="leaf" x="10" y="10" width="44" height="44" fill="context-fill" filter="url(#f)"/>
+  </defs>
+  <use href="#leaf" fill="url(#p)"/>"##,
+    ));
+}
+
+/// A stylesheet geometry declaration that could round the filtered target is
+/// already the `rx`/`ry` property's own named departure. Strict refuses at the
+/// sheet; best effort records that declaration as ignored before compiling the
+/// sharp rectangle it actually represents. The filter profile must not claim
+/// to consume the missing geometry property or duplicate its refusal.
+#[test]
+fn stylesheet_rect_radius_keeps_its_own_departure_before_pattern_filtering() {
+    for property in ["rx", "ry"] {
+        let source = document(&format!(
+            r##"  <style>.rounded {{ {property}: 12px; }}</style>
+  <rect width="64" height="64" fill="white"/>
+  <defs>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="8" height="8"><rect width="4" height="8" fill="#16a34a"/></pattern>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="64" height="64"><feGaussianBlur stdDeviation="2"/></filter>
+  </defs>
+  <rect class="rounded" x="10" y="10" width="44" height="44" fill="url(#p)" filter="url(#f)"/>"##
+        ));
+        let strict = SvgFrameSource::from_standalone_svg(source.as_str(), viewport())
+            .expect_err("strict refuses the unrepresented geometry property");
+        assert!(
+            strict
+                .to_string()
+                .contains(&format!("stylesheet declares {property}")),
+            "{property}: {strict}"
+        );
+
+        let best = SvgFrameSource::from_standalone_svg_best_effort(source.as_str(), viewport())
+            .expect("best effort declares the property departure");
+        let declared: Vec<_> = best
+            .degradations()
+            .iter()
+            .filter(|degradation| degradation.action() == DegradationAction::DeclarationIgnored)
+            .collect();
+        assert_eq!(declared.len(), 1, "{property}: {declared:?}");
+        assert!(
+            declared[0]
+                .reason()
+                .contains(&format!("stylesheet declares {property}")),
+            "{property}: {}",
+            declared[0].reason()
+        );
+        assert!(
+            best.degradations()
+                .iter()
+                .all(|degradation| degradation.action() != DegradationAction::Skipped),
+            "{property}: the own-row declaration, not a duplicate filter skip, owns the gap"
+        );
+        resolved_filter(&best.base_frame());
+    }
+}
+
+#[test]
+fn context_selected_gradients_reach_the_existing_filter_precision_patrols() {
+    for (primitive, reason) in [
+        (
+            r##"<feDropShadow dx="3" dy="2" stdDeviation="2"/>"##,
+            "native-shadow source-layer precision boundary",
+        ),
+        (
+            r##"<feConvolveMatrix order="3" kernelMatrix="0 -1 0 -1 5 -1 0 -1 0"/>"##,
+            "convolution-filter paint-server precision boundary",
+        ),
+        (
+            r##"<feMorphology operator="dilate" radius="2"/>"##,
+            "morphology paint-server precision boundary",
+        ),
+        (
+            r##"<feComponentTransfer><feFuncR type="linear" slope=".4"/></feComponentTransfer>"##,
+            "table-filter paint-server precision boundary",
+        ),
+        (
+            r##"<feColorMatrix type="saturate" values=".2"/>"##,
+            "color-matrix source-layer precision boundary",
+        ),
+        (
+            r##"<feFlood flood-color="#e11d48" result="f"/><feComposite in="SourceGraphic" in2="f" operator="arithmetic" k1=".5" k2=".5"/>"##,
+            "translucent-source composition precision boundary",
+        ),
+    ] {
+        assert_target_skip(
+            &document(&format!(
+                r##"  <rect width="64" height="64" fill="white"/>
+  <defs>
+    <linearGradient id="g"><stop stop-color="#e11d48"/><stop offset="1" stop-color="#2563eb"/></linearGradient>
+    <filter id="f" filterUnits="userSpaceOnUse" primitiveUnits="userSpaceOnUse" x="0" y="0" width="64" height="64" color-interpolation-filters="sRGB">{primitive}</filter>
+    <rect id="leaf" x="10" y="10" width="44" height="44" fill="context-fill" filter="url(#f)"/>
+  </defs>
+  <use href="#leaf" fill="url(#g)"/>"##
+            )),
+            reason,
+        );
+    }
+}
+
+#[test]
+fn filtered_patterns_refuse_curved_and_rounded_source_profiles() {
+    for (primitive, target) in [
+        (
+            r##"<feOffset dx="3" dy="2"/>"##,
+            r##"<path d="M8 49 C13 5 51 5 56 49 C45 37 19 37 8 49 Z" fill="url(#p)" filter="url(#f)"/>"##,
+        ),
+        (
+            r##"<feGaussianBlur stdDeviation="2"/>"##,
+            r##"<rect x="8" y="10" width="48" height="44" rx="13" fill="url(#p)" filter="url(#f)"/>"##,
+        ),
+    ] {
+        assert_target_skip(
+            &document(&format!(
+                r##"  <rect width="64" height="64" fill="white"/>
+  <defs>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="8" height="8"><rect width="4" height="8" fill="#16a34a"/></pattern>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="64" height="64" color-interpolation-filters="sRGB">{primitive}</filter>
+  </defs>
+  {target}"##
+            )),
+            "filtered-pattern coverage precision boundary",
+        );
+    }
+}
+
 #[test]
 fn filtered_descendants_refuse_same_scope_clip_and_partial_opacity() {
     let defs = r##"  <defs>

crates/websem/tests/pattern_contract.rs

@@ -9,7 +9,7 @@
 mod support;
 
 use cg::{CGColor, Paint};
-use rframe::{Frame, PatternPaint};
+use rframe::{Frame, FrameItem, PatternPaint, ScopeEffect};
 use support::render_through_n0;
 use websem::{DegradationAction, InitialViewport, SvgFrameSource};
 
@@ -275,6 +275,68 @@ fn href_beats_xlink_and_the_first_local_content_owner_wins() {
     assert_eq!(solid_of(paint), CGColor::from_rgb(255, 0, 0));
 }
 
+#[test]
+fn filters_inside_pattern_content_keep_the_measured_source_programs() {
+    let frame = admit_both(&document(
+        r##"  <defs>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="16" height="16"
+            color-interpolation-filters="sRGB"><feGaussianBlur stdDeviation="2"/></filter>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16">
+      <rect x="4" y="4" width="8" height="8" fill="#16a34a" filter="url(#f)"/>
+    </pattern>
+  </defs>
+  <rect width="64" height="64" fill="url(#p)"/>"##,
+    ));
+    let source = pattern_of(&frame, 0);
+    assert!(source.items().iter().any(|item| {
+        matches!(
+            item,
+            FrameItem::ScopeBegin(scope) if matches!(scope.effect, ScopeEffect::Filter(_))
+        )
+    }));
+
+    let nested = admit_both(&document(
+        r##"  <defs>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="16" height="16"
+            color-interpolation-filters="sRGB"><feGaussianBlur stdDeviation="2"/></filter>
+    <pattern id="q" patternUnits="userSpaceOnUse" width="4" height="4"><rect width="2" height="4" fill="#e11d48"/></pattern>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16">
+      <rect width="16" height="16" fill="url(#q)" filter="url(#f)"/>
+    </pattern>
+  </defs>
+  <rect width="64" height="64" fill="url(#p)"/>"##,
+    ));
+    assert!(pattern_of(&nested, 0).items().iter().any(|item| {
+        matches!(
+            item,
+            FrameItem::ScopeBegin(scope) if matches!(scope.effect, ScopeEffect::Filter(_))
+        )
+    }));
+
+    let multi_draw = admit_both(&document(
+        r##"  <defs>
+    <filter id="f" filterUnits="userSpaceOnUse" x="0" y="0" width="16" height="16"
+            color-interpolation-filters="sRGB"><feGaussianBlur stdDeviation="2"/></filter>
+    <pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16">
+      <g filter="url(#f)"><rect width="8" height="16" fill="#e11d48"/><rect x="8" width="8" height="16" fill="#2563eb"/></g>
+    </pattern>
+  </defs>
+  <rect width="64" height="64" fill="url(#p)"/>"##,
+    ));
+    let source = pattern_of(&multi_draw, 0);
+    assert_eq!(
+        source.items().nodes().count(),
+        2,
+        "the P2 group-filter profile intentionally carries both source draws"
+    );
+    assert!(source.items().iter().any(|item| {
+        matches!(
+            item,
+            FrameItem::ScopeBegin(scope) if matches!(scope.effect, ScopeEffect::Filter(_))
+        )
+    }));
+}
+
 #[test]
 fn every_measured_picture_shader_boundary_refuses_in_both_admissions() {
     let cases = [
@@ -290,10 +352,6 @@ fn every_measured_picture_shader_boundary_refuses_in_both_admissions() {
             r##"<pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16"><g opacity=".5"><rect width="8" height="16" fill="red"/><rect x="8" width="8" height="16" fill="blue"/></g></pattern>"##,
             "source-effect precision boundary",
         ),
-        (
-            r##"<filter id="f"><feGaussianBlur stdDeviation="2"/></filter><pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16"><rect x="4" y="4" width="8" height="8" fill="red" filter="url(#f)"/></pattern>"##,
-            "filter composition outside the admitted pattern source slice",
-        ),
         (
             r##"<pattern id="q" patternUnits="userSpaceOnUse" width="8" height="8"><rect width="8" height="8" fill="red"/></pattern><pattern id="p" patternUnits="userSpaceOnUse" width="16" height="16"><rect width="16" height="16" fill="url(#q)"/><rect width="4" height="4" fill="white"/></pattern>"##,
             "composition precision boundary",