More granular font insertion control

Author: valadaptive

crates/egui/src/context.rs

@@ -575,6 +575,20 @@ impl ContextImpl {
                     match family.priority {
                         FontPriority::Highest => fam.insert(0, font.name.clone()),
                         FontPriority::Lowest => fam.push(font.name.clone()),
+                        FontPriority::Above(name) => {
+                            let position = fam
+                                .iter()
+                                .position(|f| f == name.as_ref())
+                                .unwrap_or(fam.len());
+                            fam.insert(position, font.name.clone());
+                        }
+                        FontPriority::Below(name) => {
+                            let position = fam
+                                .iter()
+                                .position(|f| f == name.as_ref())
+                                .unwrap_or(fam.len() - 1);
+                            fam.insert(position + 1, font.name.clone());
+                        }
                     }
                 }
                 font_definitions

crates/epaint/src/text/fonts.rs

@@ -209,6 +209,16 @@ pub enum FontPriority {
     ///
     /// This font will only be used if the glyph is not found in any of the previously installed fonts.
     Lowest,
+
+    /// Insert this font above the given family in the priority stack.
+    ///
+    /// If the given family cannot be found, this font will be placed at the lowest priority.
+    Above(Cow<'static, str>),
+
+    /// Insert this font below the given family in the priority stack.
+    ///
+    /// If the given family cannot be found, this font will be placed at the lowest priority.
+    Below(Cow<'static, str>),
 }
 
 impl FontInsert {

crates/epaint/src/text/style.rs

@@ -599,7 +599,7 @@ pub mod named_variants {
         /// Enables display of font-specific alternate annotation forms.
         pub annotation: u16,
         /// Selects the way East Asian glyphs are rendered.
-        east_asian_variant: EastAsianVariant,
+        pub east_asian_variant: EastAsianVariant,
         /// Selects the width variants of East Asian glyphs.
         pub east_asian_width: Option<EastAsianWidth>,
         /// Enables display of ruby (superscript-like annotations) variant glyphs.