diff --git a/src/lib/x11_rgba.c b/src/lib/x11_rgba.c
index 3e5d1f0..c05b3d3 100644
--- a/src/lib/x11_rgba.c
+++ b/src/lib/x11_rgba.c
@@ -2864,7 +2864,7 @@ __imlib_RGBA_init(void *rd, void *gd, void *bd, int depth, int palette_type)
 }
 
 static void
-__imlib_RGBA_to_RGB565_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB565_fast(const uint32_t * src, int src_jump,
                             uint8_t * dst, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -2931,7 +2931,7 @@ __imlib_RGBA_to_RGB565_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB565_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB565_dither(const uint32_t * src, int src_jump,
                               uint8_t * dst, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3000,7 +3000,7 @@ __imlib_RGBA_to_RGB565_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_BGR565_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR565_fast(const uint32_t * src, int src_jump,
                             uint8_t * dst, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3067,7 +3067,7 @@ __imlib_RGBA_to_BGR565_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_BGR565_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR565_dither(const uint32_t * src, int src_jump,
                               uint8_t * dst, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3136,7 +3136,7 @@ __imlib_RGBA_to_BGR565_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB555_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB555_fast(const uint32_t * src, int src_jump,
                             uint8_t * dst, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3203,7 +3203,7 @@ __imlib_RGBA_to_RGB555_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB555_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB555_dither(const uint32_t * src, int src_jump,
                               uint8_t * dst, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3272,7 +3272,7 @@ __imlib_RGBA_to_RGB555_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_BGR555_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR555_fast(const uint32_t * src, int src_jump,
                             uint8_t * dst, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3339,7 +3339,7 @@ __imlib_RGBA_to_BGR555_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_BGR555_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR555_dither(const uint32_t * src, int src_jump,
                               uint8_t * dst, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3408,7 +3408,7 @@ __imlib_RGBA_to_BGR555_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB332_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB332_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3503,7 +3503,7 @@ __imlib_RGBA_to_RGB332_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB332_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB332_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3580,7 +3580,7 @@ __imlib_RGBA_to_RGB332_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB666_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB666_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3675,7 +3675,7 @@ __imlib_RGBA_to_RGB666_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB666_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB666_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3752,7 +3752,7 @@ __imlib_RGBA_to_RGB666_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB232_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB232_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -3847,7 +3847,7 @@ __imlib_RGBA_to_RGB232_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB232_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB232_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -3924,7 +3924,7 @@ __imlib_RGBA_to_RGB232_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB222_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB222_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4019,7 +4019,7 @@ __imlib_RGBA_to_RGB222_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB222_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB222_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -4096,7 +4096,7 @@ __imlib_RGBA_to_RGB222_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB221_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB221_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4191,7 +4191,7 @@ __imlib_RGBA_to_RGB221_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB221_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB221_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -4268,7 +4268,7 @@ __imlib_RGBA_to_RGB221_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB121_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB121_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4363,7 +4363,7 @@ __imlib_RGBA_to_RGB121_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB121_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB121_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -4440,7 +4440,7 @@ __imlib_RGBA_to_RGB121_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB111_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB111_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4535,7 +4535,7 @@ __imlib_RGBA_to_RGB111_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB111_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB111_dither(const uint32_t * src, int src_jump,
                               uint8_t * dest, int dow,
                               int width, int height, int dx, int dy)
 {
@@ -4612,7 +4612,7 @@ __imlib_RGBA_to_RGB111_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB1_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB1_fast(const uint32_t * src, int src_jump,
                           uint8_t * dest, int dow,
                           int width, int height, int dx, int dy)
 {
@@ -4634,7 +4634,7 @@ __imlib_RGBA_to_RGB1_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB1_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB1_dither(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4656,7 +4656,7 @@ __imlib_RGBA_to_RGB1_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_A1_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_A1_fast(const uint32_t * src, int src_jump,
                         uint8_t * dest, int dow,
                         int width, int height, int dx, int dy, int threshold)
 {
@@ -4678,7 +4678,7 @@ __imlib_RGBA_to_A1_fast(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_A1_dither(uint32_t * src, int src_jump,
+__imlib_RGBA_to_A1_dither(const uint32_t * src, int src_jump,
                           uint8_t * dest, int dow,
                           int width, int height, int dx, int dy, int threshold)
 {
@@ -4700,7 +4700,7 @@ __imlib_RGBA_to_A1_dither(uint32_t * src, int src_jump,
 }
 
 static void
-__imlib_RGBA_to_RGB8888_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB8888_fast(const uint32_t * src, int src_jump,
                              uint8_t * dst, int dow,
                              int width, int height, int dx, int dy)
 {
@@ -4726,7 +4726,7 @@ __imlib_RGBA_to_RGB8888_fast(uint32_t * src, int src_jump,
 
 #if 0                           /* Unused */
 static void
-__imlib_RGBA_to_BGR8888_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR8888_fast(const uint32_t * src, int src_jump,
                              uint8_t * dst, int dow,
                              int width, int height, int dx, int dy)
 {
@@ -4750,7 +4750,7 @@ __imlib_RGBA_to_BGR8888_fast(uint32_t * src, int src_jump,
 #endif
 
 static void
-__imlib_RGBA_to_RGB888_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_RGB888_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4773,7 +4773,7 @@ __imlib_RGBA_to_RGB888_fast(uint32_t * src, int src_jump,
 
 #if 0                           /* Unused */
 static void
-__imlib_RGBA_to_BGR888_fast(uint32_t * src, int src_jump,
+__imlib_RGBA_to_BGR888_fast(const uint32_t * src, int src_jump,
                             uint8_t * dest, int dow,
                             int width, int height, int dx, int dy)
 {
@@ -4797,7 +4797,7 @@ __imlib_RGBA_to_BGR888_fast(uint32_t * src, int src_jump,
 
 #if 0                           /* Unused */
 static void
-__imlib_RGBA_to_Nothing(uint32_t * src, int src_jump,
+__imlib_RGBA_to_Nothing(const uint32_t * src, int src_jump,
                         uint8_t * dest, int dow,
                         int width, int height, int dx, int dy)
 {
diff --git a/src/lib/x11_rgba.h b/src/lib/x11_rgba.h
index afe406d..e7a396a 100644
--- a/src/lib/x11_rgba.h
+++ b/src/lib/x11_rgba.h
@@ -2,6 +2,7 @@
 #define X11_RGBA_H 1
 
 #include "types.h"
+#include "x11_context.h"
 
 #define DM_BS1 (8 + 3)
 #define DM_BS2 (8)
@@ -12,9 +13,9 @@ void                __imlib_RGBASetupContext(Context * ct);
 void                __imlib_RGBA_init(void *rd, void *gd, void *bd, int depth,
                                       int palette_type);
 
-typedef void        (*ImlibRGBAFunction)(uint32_t *, int, uint8_t *,
+typedef void        (*ImlibRGBAFunction)(const uint32_t *, int, uint8_t *,
                                          int, int, int, int, int);
-typedef void        (*ImlibMaskFunction)(uint32_t *, int, uint8_t *,
+typedef void        (*ImlibMaskFunction)(const uint32_t *, int, uint8_t *,
                                          int, int, int, int, int, int);
 ImlibRGBAFunction   __imlib_GetRGBAFunction(int depth, unsigned long rm,
                                             unsigned long gm, unsigned long bm,
@@ -22,14 +23,14 @@ ImlibRGBAFunction   __imlib_GetRGBAFunction(int depth, unsigned long rm,
 ImlibMaskFunction   __imlib_GetMaskFunction(char hiq);
 
 #ifdef DO_MMX_ASM
-void                __imlib_mmx_rgb555_fast(uint32_t *, int, uint8_t *, int,
-                                            int, int, int, int);
-void                __imlib_mmx_bgr555_fast(uint32_t *, int, uint8_t *, int,
-                                            int, int, int, int);
-void                __imlib_mmx_rgb565_fast(uint32_t *, int, uint8_t *, int,
-                                            int, int, int, int);
-void                __imlib_mmx_bgr565_fast(uint32_t *, int, uint8_t *, int,
-                                            int, int, int, int);
+void                __imlib_mmx_rgb555_fast(const uint32_t *, int, uint8_t *,
+                                            int, int, int, int, int);
+void                __imlib_mmx_bgr555_fast(const uint32_t *, int, uint8_t *,
+                                            int, int, int, int, int);
+void                __imlib_mmx_rgb565_fast(const uint32_t *, int, uint8_t *,
+                                            int, int, int, int, int);
+void                __imlib_mmx_bgr565_fast(const uint32_t *, int, uint8_t *,
+                                            int, int, int, int, int);
 #endif
 
 #endif /* X11_RGBA_H */