diff --git a/src/gpufont/font.hpp b/src/gpufont/font.hpp
index 77fad40..175e702 100644
--- a/src/gpufont/font.hpp
+++ b/src/gpufont/font.hpp
@@ -15,9 +15,15 @@
 #include FT_FREETYPE_H
 #include FT_MULTIPLE_MASTERS_H
 
-#define F26DOT6_TO_DOUBLE(x) (1 / 64. * double(x))
-#define F16DOT16_TO_DOUBLE(x) (1 / 65536. * double(x))
-#define DOUBLE_TO_F16DOT16(x) FT_Fixed(65536. * x)
+#ifndef F26DOT6_TO_DOUBLE
+    #define F26DOT6_TO_DOUBLE(x) (1 / 64. * double(x))
+#endif
+#ifndef F16DOT16_TO_DOUBLE
+    #define F16DOT16_TO_DOUBLE(x) (1 / 65536. * double(x))
+#endif
+#ifndef DOUBLE_TO_F16DOT16
+    #define DOUBLE_TO_F16DOT16(x) FT_Fixed(65536. * x)
+#endif
 
 namespace ofxGPUFont {