Fix memory leak from font resizing

The source of the leak was loading up multiple copies of the FT_face
even when not necessary. Fonts are now appropriately cached for
FreeType when going through the `Rasterize::load_font` API.

Additionally, textures in the glyph cache are now reused.

The result of this is that resizing to already loaded fonts is free
from a memory consumption perspective.

1 files changed, 8 insertions, 0 deletions

diff --git a/font/src/lib.rs b/font/src/lib.rs
index 181fd88c..513dacdd 100644
--- a/font/src/lib.rs
+++ b/font/src/lib.rs
@@ -172,6 +172,14 @@ impl Size {
     }
 }
 
+impl ::std::ops::Add for Size {
+    type Output = Size;
+
+    fn add(self, other: Size) -> Size {
+        Size(self.0.saturating_add(other.0))
+    }
+}
+
 pub struct RasterizedGlyph {
     pub c: char,
     pub width: i32,