Only use relevant info from Attrs as a key in font_matches_cache

`Attrs` contains info like color and metadata which are not relevant
 to font matching.

 So, add a new struct `FontMatchAttrs` which only contains the relevant
 info, and use it as a key in `FontSystem`'s `font_matches_cache`.

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

src/attrs.rs

@@ -191,6 +191,26 @@ impl<'a> Attrs<'a> {
     }
 }
 
+/// Font-specific part of [`Attrs`] to be used for matching
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub struct FontMatchAttrs {
+    family: FamilyOwned,
+    stretch: Stretch,
+    style: Style,
+    weight: Weight,
+}
+
+impl<'a> From<Attrs<'a>> for FontMatchAttrs {
+    fn from(attrs: Attrs<'a>) -> Self {
+        Self {
+            family: FamilyOwned::new(attrs.family),
+            stretch: attrs.stretch,
+            style: attrs.style,
+            weight: attrs.weight,
+        }
+    }
+}
+
 /// An owned version of [`Attrs`]
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 pub struct AttrsOwned {

src/font/system.rs

@@ -1,4 +1,4 @@
-use crate::{Attrs, AttrsOwned, Font, HashMap, ShapePlanCache};
+use crate::{Attrs, Font, FontMatchAttrs, HashMap, ShapePlanCache};
 use alloc::string::String;
 use alloc::sync::Arc;
 use alloc::vec::Vec;
@@ -27,7 +27,7 @@ pub struct FontSystem {
     font_cache: HashMap<fontdb::ID, Option<Arc<Font>>>,
 
     /// Cache for font matches.
-    font_matches_cache: HashMap<AttrsOwned, Arc<Vec<FontMatchKey>>>,
+    font_matches_cache: HashMap<FontMatchAttrs, Arc<Vec<FontMatchKey>>>,
 
     /// Cache for rustybuzz shape plans.
     shape_plan_cache: ShapePlanCache,
@@ -141,7 +141,7 @@ impl FontSystem {
 
         self.font_matches_cache
             //TODO: do not create AttrsOwned unless entry does not already exist
-            .entry(AttrsOwned::new(attrs))
+            .entry(attrs.into())
             .or_insert_with(|| {
                 #[cfg(all(feature = "std", not(target_arch = "wasm32")))]
                 let now = std::time::Instant::now();