Store a sorted list of monospace font ids in font system

Signed-off-by: Mohammad AlSaleh <CE.Mohammad.AlSaleh@gmail.com>

src/font/system.rs

@@ -86,6 +86,9 @@ pub struct FontSystem {
     /// Cache for loaded fonts from the database.
     font_cache: HashMap<fontdb::ID, Option<Arc<Font>>>,
 
+    /// Sorted unique ID's of all Monospace fonts in DB
+    monospace_font_ids: Vec<fontdb::ID>,
+
     /// Cache for font codepoint support info
     font_codepoint_support_info_cache: HashMap<fontdb::ID, FontCachedCodepointSupportInfo>,
 
@@ -141,9 +144,19 @@ impl FontSystem {
 
     /// Create a new [`FontSystem`] with a pre-specified locale and font database.
     pub fn new_with_locale_and_db(locale: String, db: fontdb::Database) -> Self {
+        let mut monospace_font_ids = db
+            .faces()
+            .filter(|face_info| {
+                face_info.monospaced && !face_info.post_script_name.contains("Emoji")
+            })
+            .map(|face_info| face_info.id)
+            .collect::<Vec<_>>();
+        monospace_font_ids.sort();
+
         Self {
             locale,
             db,
+            monospace_font_ids,
             font_cache: Default::default(),
             font_matches_cache: Default::default(),
             font_codepoint_support_info_cache: Default::default(),
@@ -202,6 +215,10 @@ impl FontSystem {
             .clone()
     }
 
+    pub fn is_monospace(&self, id: fontdb::ID) -> bool {
+        self.monospace_font_ids.binary_search(&id).is_ok()
+    }
+
     #[inline(always)]
     pub fn get_font_supported_codepoints_in_word(
         &mut self,