diff --git a/minuitwrp/minui.h b/minuitwrp/minui.h
index cb9f8a3..699b08c 100644
--- a/minuitwrp/minui.h
+++ b/minuitwrp/minui.h
@@ -17,7 +17,16 @@
 #ifndef _MINUI_H_
 #define _MINUI_H_
 
-typedef void* gr_surface;
+typedef struct {
+    int width;
+    int height;
+    int row_bytes;
+    int pixel_bytes;
+    unsigned char* data;
+} GRSurface;
+
+typedef GRSurface* gr_surface;
+
 typedef unsigned short gr_pixel;
 
 #define FONT_TYPE_TWRP 0