Improved mono fallback

src/font/fallback/mod.rs

@@ -26,7 +26,8 @@ mod platform;
 
 pub struct FontFallbackIter<'a> {
     fonts: &'a [Font<'a>],
-    default_family_opt: Option<&'a str>,
+    default_families: &'a [&'a str],
+    default_i: usize,
     scripts: Vec<Script>,
     locale: &'a str,
     script_i: (usize, usize),
@@ -36,10 +37,11 @@ pub struct FontFallbackIter<'a> {
 }
 
 impl<'a> FontFallbackIter<'a> {
-    pub fn new(fonts: &'a [Font<'a>], default_family_opt: Option<&'a str>, scripts: Vec<Script>, locale: &'a str) -> Self {
+    pub fn new(fonts: &'a [Font<'a>], default_families: &'a [&'a str], scripts: Vec<Script>, locale: &'a str) -> Self {
         Self {
             fonts,
-            default_family_opt,
+            default_families,
+            default_i: 0,
             scripts,
             locale,
             script_i: (0, 0),
@@ -82,7 +84,10 @@ 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() {
+        while self.default_i < self.default_families.len() {
+            let default_family = self.default_families[self.default_i];
+            self.default_i += 1;
+
             for font in self.fonts.iter() {
                 if font.info.family == default_family {
                     return Some(font);

src/font/fallback/unix.rs

@@ -4,10 +4,18 @@ use unicode_script::Script;
 pub fn common_fallback() -> &'static [&'static str] {
     //TODO: abstract style (sans/serif/monospaced)
     &[
+        /* Sans-serif fallbacks */
+        "Noto Sans",
         "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?
     ]

src/font/matches.rs

@@ -127,7 +127,12 @@ impl<'a> FontMatches<'a> {
         );
 
         //TODO: configure default family
-        let mut font_iter = FontFallbackIter::new(&self.fonts, Some("Fira Sans"), scripts, &self.locale);
+        let mut font_iter = FontFallbackIter::new(
+            &self.fonts,
+            &["Fira Sans", "Fira Mono"],
+            scripts,
+            &self.locale
+        );
 
         let (mut glyphs, mut missing) = self.shape_fallback(
             font_iter.next().unwrap(),