From f91cb3ce0f2e178e09a124429fd0bab69247b465 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Thu, 13 Oct 2022 12:12:11 -0600
Subject: [PATCH] Script specific font matching

---
 examples/text/src/font/fallback/mod.rs  | 25 +++++++++++++---
 examples/text/src/font/fallback/unix.rs | 39 +++++++++++++++++++++++--
 examples/text/src/font/matches.rs       | 18 +++++++-----
 3 files changed, 68 insertions(+), 14 deletions(-)

diff --git a/examples/text/src/font/fallback/mod.rs b/examples/text/src/font/fallback/mod.rs
index 4551b015..03b4f072 100644
--- a/examples/text/src/font/fallback/mod.rs
+++ b/examples/text/src/font/fallback/mod.rs
@@ -24,19 +24,21 @@ mod windows;
 
 pub struct FontFallbackIter<'a> {
     fonts: &'a [Font<'a>],
-    locale: &'a str,
+    default_family_opt: Option<&'a str>,
     scripts: Vec<Script>,
+    locale: &'a str,
     script_i: (usize, usize),
     common_i: usize,
     other_i: usize,
 }
 
 impl<'a> FontFallbackIter<'a> {
-    pub fn new(fonts: &'a [Font<'a>], scripts: Vec<Script>, locale: &'a str) -> Self {
+    pub fn new(fonts: &'a [Font<'a>], default_family_opt: Option<&'a str>, scripts: Vec<Script>, locale: &'a str) -> Self {
         Self {
             fonts,
-            locale,
+            default_family_opt,
             scripts,
+            locale,
             script_i: (0, 0),
             common_i: 0,
             other_i: 0,
@@ -47,8 +49,18 @@ impl<'a> FontFallbackIter<'a> {
 impl<'a> Iterator for FontFallbackIter<'a> {
     type Item = &'a Font<'a>;
     fn next(&mut self) -> Option<Self::Item> {
+        if let Some(default_family) = self.default_family_opt.take() {
+            for font in self.fonts.iter() {
+                if font.info.family == default_family {
+                    return Some(font);
+                }
+            }
+        }
+
         while self.script_i.0 < self.scripts.len() {
-            let script_families = script_fallback(&self.scripts[self.script_i.0], self.locale);
+            let script = self.scripts[self.script_i.0];
+
+            let script_families = script_fallback(&script, self.locale);
             while self.script_i.1 < script_families.len() {
                 let script_family = script_families[self.script_i.1];
                 self.script_i.1 += 1;
@@ -57,7 +69,9 @@ impl<'a> Iterator for FontFallbackIter<'a> {
                         return Some(font);
                     }
                 }
+                log::warn!("failed to find family '{}' for script {:?} and locale '{}'", script_family, script, self.locale)
             }
+
             self.script_i.0 += 1;
             self.script_i.1 = 0;
         }
@@ -68,9 +82,11 @@ impl<'a> Iterator for FontFallbackIter<'a> {
             self.common_i += 1;
             for font in self.fonts.iter() {
                 if font.info.family == common_family {
+                    log::debug!("Trying '{}' for scripts {:?} and locale '{}'", font.info.family, self.scripts, self.locale);
                     return Some(font);
                 }
             }
+            log::warn!("failed to find family '{}'", common_family)
         }
 
         //TODO: do we need to do this?
@@ -78,6 +94,7 @@ impl<'a> Iterator for FontFallbackIter<'a> {
         while self.other_i < self.fonts.len() {
             let font = &self.fonts[self.other_i];
             self.other_i += 1;
+            log::info!("Trying '{}' for scripts {:?} and locale '{}'", font.info.family, self.scripts, self.locale);
             return Some(font);
         }
 
diff --git a/examples/text/src/font/fallback/unix.rs b/examples/text/src/font/fallback/unix.rs
index 5eb799d8..25085b71 100644
--- a/examples/text/src/font/fallback/unix.rs
+++ b/examples/text/src/font/fallback/unix.rs
@@ -6,7 +6,9 @@ pub fn common_fallback() -> &'static [&'static str] {
     &[
         "Fira Sans",
         "DejaVu Sans",
-        "DejaVu Serif",
+        //"FreeSans",
+        "Noto Sans Symbols",
+        "Noto Sans Symbols2",
         "Noto Color Emoji",
     ]
 }
@@ -15,6 +17,17 @@ pub fn common_fallback() -> &'static [&'static str] {
 pub fn script_fallback(script: &Script, locale: &str) -> &'static [&'static str] {
     //TODO: abstract style (sans/serif/monospaced)
     match script {
+        Script::Adlam => &["Noto Sans Adlam"],
+        Script::Arabic => &["Noto Sans Arabic"],
+        Script::Bengali => &["Noto Sans Bengali"],
+        Script::Chakma => &["Noto Sans Chakma"],
+        Script::Cherokee => &["Noto Sans Cherokee"],
+        Script::Devanagari => &["Noto Sans Devanagari"],
+        Script::Ethiopic => &["Noto Sans Ethiopic"],
+        Script::Hangul => &["Noto Sans CJK KR"],
+        Script::Grantha => &["Noto Sans Grantha"],
+        Script::Gujarati => &["Noto Sans Gujarati"],
+        Script::Gurmukhi => &["Noto Sans Gurmukhi"],
         Script::Han => match locale {
             // Japan
             "ja" => &["Noto Sans CJK JA"],
@@ -28,7 +41,29 @@ pub fn script_fallback(script: &Script, locale: &str) -> &'static [&'static str]
             "zh-TW" => &["Noto Sans CJK TC"],
             // Simplified Chinese is the default
             _ => &["Noto Sans CJK SC"],
-        }
+        },
+        Script::Hiragana => &["Noto Sans CJK JP"],
+        Script::Javanese => &["Noto Sans Javanese"],
+        Script::Kannada => &["Noto Sans Kannada"],
+        Script::Katakana => &["Noto Sans CJK JP"],
+        Script::Khmer => &["Noto Sans Khmer"],
+        Script::Malayalam => &["Noto Sans Malayalam"],
+        Script::Mongolian => &["Noto Sans Mongolian"],
+        Script::Myanmar => &["Noto Sans Myanmar"],
+        Script::Sinhala => &["Noto Sans Sinhala"],
+        Script::Syriac => &["Noto Sans Syriac"],
+        Script::Tai_Le => &["Noto Sans Tai Le"],
+        Script::Tai_Tham => &["Noto Sans Tai Tham"],
+        Script::Tai_Viet => &["Noto Sans Tai Viet"],
+        Script::Tagalog => &["Noto Sans Tagalog"],
+        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::Vai => &["Noto Sans Vai"],
+        Script::Yi => &["Noto Sans Yi", /*TODO: Choose a CJK font*/],
         _ => &[],
     }
 }
diff --git a/examples/text/src/font/matches.rs b/examples/text/src/font/matches.rs
index dcefd232..3ed2e00c 100644
--- a/examples/text/src/font/matches.rs
+++ b/examples/text/src/font/matches.rs
@@ -134,7 +134,7 @@ impl<'a> FontMatches<'a> {
                 &line[start_word..end_word],
             );
         } else {
-            log::debug!(
+            log::trace!(
                 "    Word {:?}{}: '{}'",
                 scripts,
                 if blank { " BLANK" } else { "" },
@@ -142,7 +142,8 @@ impl<'a> FontMatches<'a> {
             );
         }
 
-        let mut font_iter = FontFallbackIter::new(&self.fonts, scripts, &self.locale);
+        //TODO: configure default family
+        let mut font_iter = FontFallbackIter::new(&self.fonts, Some("Fira Sans"), scripts, &self.locale);
 
         let (mut glyphs, mut missing) = self.shape_fallback(
             font_iter.next().unwrap(),
@@ -154,10 +155,11 @@ impl<'a> FontMatches<'a> {
         );
 
         //TODO: improve performance!
-        while let Some(font) = font_iter.next() {
-            if missing.is_empty() {
-                break;
-            }
+        while !missing.is_empty() {
+            let font = match font_iter.next() {
+                Some(some) => some,
+                None => break,
+            };
 
             log::trace!("Evaluating fallback with font '{}'", font.info.family);
             let (mut fb_glyphs, fb_missing) = self.shape_fallback(
@@ -243,7 +245,7 @@ impl<'a> FontMatches<'a> {
     ) -> FontShapeSpan {
         let span = &line[start_span..end_span];
 
-        log::debug!(
+        log::trace!(
             "  Span {}: '{}'",
             if span_rtl { "RTL" } else { "LTR" },
             span
@@ -311,7 +313,7 @@ impl<'a> FontMatches<'a> {
             let para_info = &bidi.paragraphs[0];
             let line_rtl = para_info.level.is_rtl();
 
-            log::debug!("Line {}: '{}'", if line_rtl { "RTL" } else { "LTR" }, line);
+            log::trace!("Line {}: '{}'", if line_rtl { "RTL" } else { "LTR" }, line);
 
             let paragraph = unicode_bidi::Paragraph::new(&bidi, &para_info);