desktop: Support device font with a non-zero index

core/src/backend/ui.rs

@@ -22,6 +22,7 @@ pub enum FontDefinition<'a> {
         is_bold: bool,
         is_italic: bool,
         data: Vec<u8>,
+        index: u32,
     },
 }
 

core/src/library.rs

@@ -562,9 +562,11 @@ impl<'gc> Library<'gc> {
                 is_bold,
                 is_italic,
                 data,
+                index,
             } => {
                 let descriptor = FontDescriptor::from_parts(&name, is_bold, is_italic);
-                if let Ok(font) = Font::from_font_file(gc_context, descriptor, Cow::Owned(data), 0)
+                if let Ok(font) =
+                    Font::from_font_file(gc_context, descriptor, Cow::Owned(data), index)
                 {
                     let name = font.descriptor().name().to_owned();
                     info!("Loaded new device font \"{name}\" from file");

desktop/src/backends/ui.rs

@@ -288,6 +288,7 @@ impl UiBackend for DesktopUiBackend {
                             is_bold,
                             is_italic,
                             data: bytes,
+                            index: face.index,
                         }),
                         Err(e) => error!("Couldn't read font file at {path:?}: {e}"),
                     },
@@ -297,6 +298,7 @@ impl UiBackend for DesktopUiBackend {
                             is_bold,
                             is_italic,
                             data: bin.as_ref().as_ref().to_vec(),
+                            index: face.index,
                         })
                     }
                 };

tests/framework/src/backends/ui.rs

@@ -142,6 +142,7 @@ impl UiBackend for TestUiBackend {
                 is_bold,
                 is_italic,
                 data: font.bytes.clone(),
+                index: 0,
             });
             break;
         }