diff --git a/image.go b/image.go
index ee3c63d18..93fbf9619 100644
--- a/image.go
+++ b/image.go
@@ -23,6 +23,7 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/ui"
 	"image"
 	"image/color"
+	"math"
 )
 
 // Image represents an image.
@@ -47,7 +48,13 @@ func (i *Image) Clear() (err error) {
 // Fill fills the image with a solid color.
 func (i *Image) Fill(clr color.Color) (err error) {
 	i.pixels = nil
-	r, g, b, a := internal.RGBA(clr)
+	//r, g, b, a := internal.RGBA(clr)
+	cr, cg, cb, ca := clr.RGBA()
+	const max = math.MaxUint16
+	r := float64(cr) / max
+	g := float64(cg) / max
+	b := float64(cb) / max
+	a := float64(ca) / max
 	ui.Use(func(c *opengl.Context) {
 		// TODO: Change to pass color.Color
 		err = i.framebuffer.Fill(c, r, g, b, a)
diff --git a/internal/math.go b/internal/math.go
index 8e71578a4..8dbcd4cf9 100644
--- a/internal/math.go
+++ b/internal/math.go
@@ -14,11 +14,6 @@
 
 package internal
 
-import (
-	"image/color"
-	"math"
-)
-
 func NextPowerOf2Int(x int) int {
 	x -= 1
 	x |= (x >> 1)
@@ -28,13 +23,3 @@ func NextPowerOf2Int(x int) int {
 	x |= (x >> 16)
 	return x + 1
 }
-
-func RGBA(clr color.Color) (r, g, b, a float64) {
-	cr, cg, cb, ca := clr.RGBA()
-	const max = math.MaxUint16
-	r = float64(cr) / max
-	g = float64(cg) / max
-	b = float64(cb) / max
-	a = float64(ca) / max
-	return
-}