Cleaned up some duplicated pixel format-related code in Font files.

--HG--
branch : minor

src/modules/font/Rasterizer.h

@@ -49,6 +49,12 @@ class Rasterizer : public Object
 {
 public:
 
+	enum DataType
+	{
+		DATA_TRUETYPE,
+		DATA_IMAGE,
+	};
+
 	static love::Type type;
 
 	virtual ~Rasterizer();
@@ -112,6 +118,8 @@ public:
 	 **/
 	virtual float getKerning(uint32 leftglyph, uint32 rightglyph) const;
 
+	virtual DataType getDataType() const = 0;
+
 protected:
 
 	FontMetrics metrics;