diff --git a/ext/native/base/colorutil.cpp b/ext/native/base/colorutil.cpp
index bdb4bdbcb1..6074dd9be0 100644
--- a/ext/native/base/colorutil.cpp
+++ b/ext/native/base/colorutil.cpp
@@ -46,7 +46,7 @@ uint32_t colorBlend(uint32_t rgb1, uint32_t rgb2, float alpha) {
 uint32_t alphaMul(uint32_t color, float alphaMul) {
 	uint32_t rgb = color & 0xFFFFFF;
 	int32_t alpha = color >> 24;
-	alpha *= alphaMul;
+	alpha = (int32_t)(alpha * alphaMul);
 	if (alpha < 0) alpha = 0;
 	if (alpha > 255) alpha = 255;
 	return (alpha << 24) | (rgb & 0xFFFFFF);
@@ -63,52 +63,3 @@ uint32_t rgba(float r, float g, float b, float alpha) {
 uint32_t rgba_clamp(float r, float g, float b, float a) {
 	return rgba(clamp(r, 0.0f, 1.0f), clamp(g, 0.0f, 1.0f), clamp(b, 0.0f, 1.0f), clamp(a, 0.0f, 1.0f));
 }
-
-/* hsv2rgb.c
-* Convert Hue Saturation Value to Red Green Blue
-*
-* P.J. 08-Aug-98
-*
-* Reference:
-* D. F. Rogers
-* Procedural Elements for Computer Graphics
-* McGraw Hill 1985
-*/
-uint32_t hsva(float H, float S, float V, float alpha) {
-	/*
-	* Purpose:
-	* Convert HSV values to RGB values
-	* All values are in the range [0.0 .. 1.0]
-	*/
-	float F, M, N, K;
-	int	 I;
-	if ( S == 0.0 ) {
-		// Achromatic case, set level of grey
-		return rgba(V, V, V, alpha);
-	} else {
-		/*
-		* Determine levels of primary colours.
-		*/
-		if (H >= 1.0) {
-			H = 0.0;
-		} else {
-			H = H * 6;
-		}
-		I = (int) H;	 /* should be in the range 0..5 */
-		F = H - I;		 /* fractional part */
-
-		M = V * (1 - S);
-		N = V * (1 - S * F);
-		K = V * (1 - S * (1 - F));
-
-		float r, g, b;
-		if (I == 0) { r = V; g = K; b = M; }
-		else if (I == 1) { r = N; g = V; b = M; }
-		else if (I == 2) { r = M; g = V; b = K; }
-		else if (I == 3) { r = M; g = N; b = V; }
-		else if (I == 4) { r = K; g = M; b = V; }
-		else if (I == 5) { r = V; g = M; b = N; }
-		else return 0;
-		return rgba(r, g, b, alpha);
-	}
-}
diff --git a/ext/native/base/colorutil.h b/ext/native/base/colorutil.h
index 0f9fa33b7a..9e8128bae1 100644
--- a/ext/native/base/colorutil.h
+++ b/ext/native/base/colorutil.h
@@ -9,7 +9,6 @@ uint32_t colorBlend(uint32_t color, uint32_t color2, float alpha);
 uint32_t alphaMul(uint32_t color, float alphaMul);
 uint32_t rgba(float r, float g, float b, float alpha);
 uint32_t rgba_clamp(float r, float g, float b, float alpha);
-uint32_t hsva(float h, float s, float v, float alpha);
 
 typedef unsigned int Color;
 
@@ -17,10 +16,3 @@ typedef unsigned int Color;
 inline Color darkenColor(Color color) {
 	return (color & 0xFF000000) | ((color >> 1) & 0x7F7F7F);
 }
-inline Color whitenColor(Color color) {
-	return ((color & 0xFF000000) | ((color >> 1) & 0x7F7F7F)) + 0x7F7F7F;
-}
-inline Color colorInterpol(Color x, Color y, int n) {
-	// TODO
-	return x;
-}