Change ColorMatrix's methods to functions

colormatrix.go

@@ -81,6 +81,32 @@ func Monochrome() ColorMatrix {
 	}
 }
 
+// ScaleColor returns a color matrix that scales a color matrix by clr.
+func ScaleColor(clr color.Color) ColorMatrix {
+	rf, gf, bf, af := rgba(clr)
+	return ColorMatrix{
+		[ColorMatrixDim - 1][ColorMatrixDim]float64{
+			{rf, 0, 0, 0, 0},
+			{0, gf, 0, 0, 0},
+			{0, 0, bf, 0, 0},
+			{0, 0, 0, af, 0},
+		},
+	}
+}
+
+// TranslateColor returns a color matrix that translates a color matrix by clr.
+func (c *ColorMatrix) Translate(clr color.Color) ColorMatrix {
+	rf, gf, bf, af := rgba(clr)
+	return ColorMatrix{
+		[ColorMatrixDim - 1][ColorMatrixDim]float64{
+			{1, 0, 0, 0, rf},
+			{0, 1, 0, 0, gf},
+			{0, 0, 1, 0, bf},
+			{0, 0, 0, 1, af},
+		},
+	}
+}
+
 // RotateHue returns a color matrix to rotate the hue
 func RotateHue(theta float64) ColorMatrix {
 	sin, cos := math.Sincos(theta)
@@ -106,22 +132,3 @@ func rgba(clr color.Color) (float64, float64, float64, float64) {
 	af := float64(a) / float64(math.MaxUint16)
 	return rf, gf, bf, af
 }
-
-// Scale scales the color matrix by clr.
-func (c *ColorMatrix) Scale(clr color.Color) {
-	rf, gf, bf, af := rgba(clr)
-	for i, e := range []float64{rf, gf, bf, af} {
-		for j := 0; j < 4; j++ {
-			c.Elements[i][j] *= e
-		}
-	}
-}
-
-// Translate translates the color matrix by clr.
-func (c *ColorMatrix) Translate(clr color.Color) {
-	rf, gf, bf, af := rgba(clr)
-	c.Elements[0][4] = rf
-	c.Elements[1][4] = gf
-	c.Elements[2][4] = bf
-	c.Elements[3][4] = af
-}

ebitenutil/debugprint.go

@@ -57,7 +57,7 @@ func (d *debugPrintState) drawText(gr ebiten.GraphicsContext, str string, x, y i
 	geom := ebiten.GeometryMatrixI()
 	geom.Concat(ebiten.TranslateGeometry(float64(x)+1, float64(y)))
 	clrm := ebiten.ColorMatrixI()
-	clrm.Scale(clr)
+	clrm.Concat(ebiten.ScaleColor(clr))
 	gr.Texture(d.textTexture).Draw(parts, geom, clrm)
 }
 

example/blocks/blocks/font.go

@@ -59,7 +59,7 @@ func drawText(context ebiten.GraphicsContext, textures *Textures, str string, x,
 	geoMat.Concat(ebiten.ScaleGeometry(float64(scale), float64(scale)))
 	geoMat.Concat(ebiten.TranslateGeometry(float64(x), float64(y)))
 	clrMat := ebiten.ColorMatrixI()
-	clrMat.Scale(clr)
+	clrMat.Concat(ebiten.ScaleColor(clr))
 	context.Texture(fontTextureId).Draw(parts, geoMat, clrMat)
 }
 

example/blocks/blocks/gamescene.go

@@ -119,7 +119,7 @@ func (s *GameScene) Draw(context ebiten.GraphicsContext, textures *Textures) {
 	geoMat.Concat(ebiten.ScaleGeometry(float64(fieldWidth)/float64(emptyWidth), float64(fieldHeight)/float64(emptyHeight)))
 	geoMat.Concat(ebiten.TranslateGeometry(20, 20)) // TODO: magic number?
 	colorMat := ebiten.ColorMatrixI()
-	colorMat.Scale(color.RGBA{0, 0, 0, 0x80})
+	colorMat.Concat(ebiten.ScaleColor(color.RGBA{0, 0, 0, 0x80}))
 	ebiten.DrawWhole(context.Texture(field), emptyWidth, emptyHeight, geoMat, colorMat)
 
 	geoMat = ebiten.GeometryMatrixI()

example/paint/main.go

@@ -57,7 +57,7 @@ func (g *Game) Draw(gr ebiten.GraphicsContext) error {
 		geo := ebiten.GeometryMatrixI()
 		geo.Concat(ebiten.TranslateGeometry(float64(mx), float64(my)))
 		clr := ebiten.ColorMatrixI()
-		clr.Scale(color.RGBA{0xff, 0xff, 0x00, 0xff})
+		clr.Concat(ebiten.ScaleColor(color.RGBA{0xff, 0xff, 0x00, 0xff}))
 		theta := 2.0 * math.Pi * float64(g.count%60) / 60.0
 		clr.Concat(ebiten.RotateHue(theta))
 		ebiten.DrawWhole(gr.RenderTarget(g.brushRenderTarget), 1, 1, geo, clr)