Fix color emoji matching when emoji with non printing variation selector

parley/src/shape/mod.rs

@@ -247,7 +247,23 @@ fn fill_cluster_in_place(
         is_emoji_or_pictograph |= info.is_emoji_or_pictograph();
         *code_unit_offset_in_string += ch.len_utf8();
 
-        let contributes_to_shaping = info.contributes_to_shaping();
+        // TODO: Explore ignoring other modifiers in determining `contributes_to_shaping`:
+        //  regional indicators, subdivision flag tag sequences, skin tone modifiers
+        //  See also: https://github.com/google/emoji-segmenter
+
+        // If the color emoji has a non-printing variation selector, ignore the variation selector.
+        // Its presentation depends on the platform and font.
+        //
+        // e.g.
+        //  - `U+270C + U+FE0F`: `✌`, force basic presentation
+        //  - `U+270C + U+FE0F`: `✌️`, force emoji presentation
+        //
+        // <https://www.unicode.org/reports/tr37/>
+        let is_emoji_with_non_printing_variation_selector =
+            is_emoji_or_pictograph && info.is_variation_selector();
+
+        let contributes_to_shaping =
+            info.contributes_to_shaping() && !is_emoji_with_non_printing_variation_selector;
         if contributes_to_shaping {
             map_len += 1;
         }

parley/src/tests/test_analysis.rs

@@ -85,6 +85,28 @@ impl TestContext {
         assert_eq!(actual, expected, "Force normalize list mismatch");
         self
     }
+
+    fn expect_is_emoji_or_pictograph_list(self, expected: Vec<bool>) -> Self {
+        let actual: Vec<_> = self
+            .layout_context
+            .info
+            .iter()
+            .map(|(info, _)| info.is_emoji_or_pictograph())
+            .collect();
+        assert_eq!(actual, expected, "Is emoji or pictograph list mismatch");
+        self
+    }
+
+    fn expect_is_variation_selector_list(self, expected: Vec<bool>) -> Self {
+        let actual: Vec<_> = self
+            .layout_context
+            .info
+            .iter()
+            .map(|(info, _)| info.is_variation_selector())
+            .collect();
+        assert_eq!(actual, expected, "Is variation selector list mismatch");
+        self
+    }
 }
 
 fn verify_analysis(
@@ -1156,3 +1178,10 @@ fn test_whitespace_contiguous_interspersed_in_latin_mixed() {
         Script::Latin,
     ]);
 }
+
+#[test]
+fn test_color_emoji_with_non_printing_variation_selector() {
+    verify_analysis("\u{270c}\u{fe0f}", |_| {})
+        .expect_is_emoji_or_pictograph_list(vec![true, false])
+        .expect_is_variation_selector_list(vec![false, true]);
+}

parley_dev/assets/fonts/noto_color_emoji/README.md

@@ -7,7 +7,8 @@ Included emoji are:
 - ✅ Check Mark - \u{2705}/`:white_check_mark:`
 - 👀 Eyes - \u{1f440}/`:eyes:`
 - 🎉 Party Popper - \u{1f389}/`:party_popper:`
-- 🤠 Face with Cowboy Hat - \u{1f920}/`cowboy_hat_face`
+- 🤠 Face with Cowboy Hat - \u{1f920}/`:cowboy_hat_face:`
+- ✌️ Victory hand - \u{270c}\u{fe0f}/`:victory_hand:`
 
 These are in the COLR format in `NotoColorEmoji-Subset` and in the CBTF format in `NotoColorEmoji-CBTF-Subset`.
 This covers all ways that Emoji are commonly packaged, and both are supported by Vello.

parley_tests/Cargo.toml

@@ -14,6 +14,9 @@ autotests = false
 name = "tests"
 path = "tests/mod.rs"
 
+[features]
+system = ["parley/system"]
+
 [dependencies]
 parley = { workspace = true, features = ["std"] }
 parley_dev = { workspace = true }

parley_tests/tests/draw.rs

@@ -172,3 +172,34 @@ fn draw_colr_emoji() {
         layout
     });
 }
+
+/// Test COLR emoji with non printing variation selector 16 rendering across different hinting,
+/// per-glyph transform, and scale configurations.
+#[cfg(all(target_os = "macos", feature = "system"))]
+#[test]
+fn draw_colr_emoji_with_non_printing_variation_selector_16() {
+    let mut env = TestEnv::new(test_name!(), None);
+    env.set_tolerance(5.0);
+
+    let collection = &mut env.font_context().collection;
+    collection.load_system_fonts();
+
+    let text = "\u{270c}\u{fe0f}\u{2705}\u{270c}\u{fe0f}";
+
+    test_with_configs(&mut env, |env| {
+        let mut builder = env.ranged_builder(text);
+        builder.push_default(StyleProperty::FontSize(24.0));
+        builder.push_default(StyleProperty::FontFamily(FontFamily::named(
+            "Apple Color Emoji",
+        )));
+        builder.push(
+            StyleProperty::FontFamily(FontFamily::named("Noto Color Emoji")),
+            0..9,
+        );
+
+        let mut layout = builder.build(text);
+        layout.break_all_lines(None);
+        layout.align(Alignment::Start, AlignmentOptions::default());
+        layout
+    });
+}

parley_tests/tests/util/env.rs

@@ -155,6 +155,11 @@ impl TestEnv {
         }
     }
 
+    #[cfg(all(target_os = "macos", feature = "system"))]
+    pub(crate) fn font_context(&mut self) -> &mut FontContext {
+        &mut self.font_cx
+    }
+
     pub(crate) fn rendering_config(&mut self) -> &mut RenderingConfig {
         &mut self.rendering_config
     }