Implement debug view and load system fonts

wgpu/src/font.rs

@@ -0,0 +1,38 @@
+pub use font_kit::family_name::FamilyName as Family;
+
+pub struct Source {
+    raw: font_kit::sources::fontconfig::FontconfigSource,
+}
+
+impl Source {
+    pub fn new() -> Self {
+        Source {
+            raw: font_kit::sources::fontconfig::FontconfigSource::new(),
+        }
+    }
+
+    pub fn load(&self, families: &[Family]) -> Vec<u8> {
+        let font = self
+            .raw
+            .select_best_match(
+                families,
+                &font_kit::properties::Properties::default(),
+            )
+            .expect("Find font");
+
+        match font {
+            font_kit::handle::Handle::Path { path, .. } => {
+                use std::io::Read;
+
+                let mut buf = Vec::new();
+                let mut reader = std::fs::File::open(path).expect("Read font");
+                let _ = reader.read_to_end(&mut buf);
+
+                buf
+            }
+            font_kit::handle::Handle::Memory { bytes, .. } => {
+                bytes.as_ref().clone()
+            }
+        }
+    }
+}