Make refactor into library

examples/text/src/font/mod.rs

@@ -0,0 +1,33 @@
+pub use self::layout::*;
+mod layout;
+
+pub use self::matches::*;
+mod matches;
+
+pub use self::shape::*;
+mod shape;
+
+pub use self::system::*;
+mod system;
+
+pub struct Font<'a> {
+    data: &'a [u8],
+    pub rustybuzz: rustybuzz::Face<'a>,
+    #[cfg(feature = "ab_glyph")]
+    pub ab_glyph: ab_glyph::FontRef<'a>,
+    #[cfg(feature = "rusttype")]
+    pub rusttype: rusttype::Font<'a>,
+}
+
+impl<'a> Font<'a> {
+    pub fn new(data: &'a [u8], index: u32) -> Option<Self> {
+        Some(Self {
+            data,
+            rustybuzz: rustybuzz::Face::from_slice(data, index)?,
+            #[cfg(feature = "ab_glyph")]
+            ab_glyph: ab_glyph::FontRef::try_from_slice_and_index(data, index).ok()?,
+            #[cfg(feature = "rusttype")]
+            rusttype: rusttype::Font::try_from_bytes_and_index(data, index)?,
+        })
+    }
+}