Honor variable font instances

2026-07-30 23:27:51 +00:00
1 parent f61493fbd1
commit 52d2d89cb6
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use unicode_script::Script;
+
+use super::Fallback;
+
+/// A platform-specific font fallback list, for Unix.
+#[derive(Debug)]
+pub struct PlatformFallback;
+
+impl Fallback for PlatformFallback {
+    fn common_fallback(&self) -> &'static [&'static str] {
+        common_fallback()
+    }
+
+    fn forbidden_fallback(&self) -> &'static [&'static str] {
+        forbidden_fallback()
+    }
+
+    fn script_fallback(
+        &self,
+        script: unicode_script::Script,
+        locale: &str,
+    ) -> &'static [&'static str] {
+        script_fallback(script, locale)
+    }
+}
+
+// Fallbacks to use after any script specific fallbacks
+fn common_fallback() -> &'static [&'static str] {
+    //TODO: abstract style (sans/serif/monospaced)
+    &[
+        /* Sans-serif fallbacks */
+        "Noto Sans",
+        /* More sans-serif fallbacks */
+        "DejaVu Sans",
+        "FreeSans",
+        /* Mono fallbacks */
+        "Noto Sans Mono",
+        "DejaVu Sans Mono",
+        "FreeMono",
+        /* Symbols fallbacks */
+        "Noto Sans Symbols",
+        "Noto Sans Symbols2",
+        /* Emoji fallbacks*/
+        "Noto Color Emoji",
+        //TODO: Add CJK script here for doublewides?
+    ]
+}
+
+// Fallbacks to never use
+fn forbidden_fallback() -> &'static [&'static str] {
+    &[]
+}
+
+fn han_unification(locale: &str) -> &'static [&'static str] {
+    match locale {
+        // Japan
+        "ja" => &["Noto Sans CJK JP"],
+        // Korea
+        "ko" => &["Noto Sans CJK KR"],
+        // Hong Kong
+        "zh-HK" => &["Noto Sans CJK HK"],
+        // Taiwan
+        "zh-TW" => &["Noto Sans CJK TC"],
+        // Simplified Chinese is the default (also catches "zh-CN" for China)
+        _ => &["Noto Sans CJK SC"],
+    }
+}
+
+// Fallbacks to use per script
+fn script_fallback(script: Script, locale: &str) -> &'static [&'static str] {
+    //TODO: abstract style (sans/serif/monospaced)
+    match script {
+        Script::Adlam => &["Noto Sans Adlam", "Noto Sans Adlam Unjoined"],
+        Script::Arabic => &["Noto Sans Arabic"],
+        Script::Armenian => &["Noto Sans Armenian"],
+        Script::Bengali => &["Noto Sans Bengali"],
+        Script::Bopomofo => han_unification(locale),
+        //TODO: DejaVu Sans would typically be selected for braille characters,
+        // but this breaks alignment when used alongside monospaced text.
+        // By requesting the use of FreeMono first, this issue can be avoided.
+        Script::Braille => &["FreeMono"],
+        Script::Buhid => &["Noto Sans Buhid"],
+        Script::Chakma => &["Noto Sans Chakma"],
+        Script::Cherokee => &["Noto Sans Cherokee"],
+        Script::Deseret => &["Noto Sans Deseret"],
+        Script::Devanagari => &["Noto Sans Devanagari"],
+        Script::Ethiopic => &["Noto Sans Ethiopic"],
+        Script::Georgian => &["Noto Sans Georgian"],
+        Script::Gothic => &["Noto Sans Gothic"],
+        Script::Grantha => &["Noto Sans Grantha"],
+        Script::Gujarati => &["Noto Sans Gujarati"],
+        Script::Gurmukhi => &["Noto Sans Gurmukhi"],
+        Script::Han => han_unification(locale),
+        Script::Hangul => han_unification("ko"),
+        Script::Hanunoo => &["Noto Sans Hanunoo"],
+        Script::Hebrew => &["Noto Sans Hebrew"],
+        Script::Hiragana => han_unification("ja"),
+        Script::Javanese => &["Noto Sans Javanese"],
+        Script::Kannada => &["Noto Sans Kannada"],
+        Script::Katakana => han_unification("ja"),
+        Script::Khmer => &["Noto Sans Khmer"],
+        Script::Lao => &["Noto Sans Lao"],
+        Script::Malayalam => &["Noto Sans Malayalam"],
+        Script::Mongolian => &["Noto Sans Mongolian"],
+        Script::Myanmar => &["Noto Sans Myanmar"],
+        Script::Oriya => &["Noto Sans Oriya"],
+        Script::Runic => &["Noto Sans Runic"],
+        Script::Sinhala => &["Noto Sans Sinhala"],
+        Script::Syriac => &["Noto Sans Syriac"],
+        Script::Tagalog => &["Noto Sans Tagalog"],
+        Script::Tagbanwa => &["Noto Sans Tagbanwa"],
+        Script::Tai_Le => &["Noto Sans Tai Le"],
+        Script::Tai_Tham => &["Noto Sans Tai Tham"],
+        Script::Tai_Viet => &["Noto Sans Tai Viet"],
+        Script::Tamil => &["Noto Sans Tamil"],
+        Script::Telugu => &["Noto Sans Telugu"],
+        Script::Thaana => &["Noto Sans Thaana"],
+        Script::Thai => &["Noto Sans Thai"],
+        //TODO: no sans script?
+        Script::Tibetan => &["Noto Serif Tibetan"],
+        Script::Tifinagh => &["Noto Sans Tifinagh"],
+        Script::Vai => &["Noto Sans Vai"],
+        //TODO: Use han_unification?
+        Script::Yi => &["Noto Sans Yi", "Noto Sans CJK SC"],
+        _ => &[],
+    }
+}