Moved lerps into graphics2d/color

color.go

@@ -110,11 +110,11 @@ func (c *ColorConv) Eval2(x, y float64) color.Color {
 	default:
 		fallthrough
 	case LerpRGBA:
-		return ColorRGBALerp(nt, c1, c2)
+		return g2dcol.ColorRGBALerp(nt, c1, c2)
 	case LerpHSL:
-		return ColorHSLLerp(nt, c1, c2)
+		return g2dcol.ColorHSLLerp(nt, c1, c2)
 	case LerpHSLs:
-		return ColorHSLLerpS(nt, c1, c2)
+		return g2dcol.ColorHSLLerpS(nt, c1, c2)
 	}
 }
 
@@ -198,11 +198,11 @@ func (c *ColorBlend) Eval2(x, y float64) color.Color {
 	default:
 		fallthrough
 	case LerpRGBA:
-		return ColorRGBALerp((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
+		return g2dcol.ColorRGBALerp((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
 	case LerpHSL:
-		return ColorHSLLerp((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
+		return g2dcol.ColorHSLLerp((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
 	case LerpHSLs:
-		return ColorHSLLerpS((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
+		return g2dcol.ColorHSLLerpS((c.Src3.Eval2(x, y)+1)/2, c.Src1.Eval2(x, y), c.Src2.Eval2(x, y))
 	}
 }
 
@@ -233,54 +233,7 @@ func (c *ColorSubstitute) Eval2(x, y float64) color.Color {
 
 // ColorRGBABiLerp calculates the color value at u, v [0,1] given colors at [0,0], [1,0], [0,1], [1,1] in RGB space.
 func ColorRGBABiLerp(u, v float64, colors []color.Color) color.RGBA {
-	c1 := ColorRGBALerp(v, colors[0], colors[2])
-	c2 := ColorRGBALerp(v, colors[1], colors[3])
-	return ColorRGBALerp(u, c1, c2)
-}
-
-// ColorRGBALerp calculates the color value at t [0,1] given a start and end color in RGB space.
-func ColorRGBALerp(t float64, start, end color.Color) color.RGBA {
-	rs, gs, bs, as := start.RGBA() // uint32 [0,0xffff]
-	re, ge, be, ae := end.RGBA()
-	rt := uint32(math.Floor((1-t)*float64(rs) + t*float64(re) + 0.5))
-	gt := uint32(math.Floor((1-t)*float64(gs) + t*float64(ge) + 0.5))
-	bt := uint32(math.Floor((1-t)*float64(bs) + t*float64(be) + 0.5))
-	at := uint32(math.Floor((1-t)*float64(as) + t*float64(ae) + 0.5))
-	rt >>= 8 // uint32 [0,0xff]
-	gt >>= 8
-	bt >>= 8
-	at >>= 8
-	return color.RGBA{uint8(rt), uint8(gt), uint8(bt), uint8(at)}
-}
-
-// ColorHSLLerp calculates the color value at t [0,1] given a start and end color in HSL space.
-func ColorHSLLerp(t float64, start, end color.Color) color.Color {
-	cs, ce := g2dcol.NewHSL(start), g2dcol.NewHSL(end)
-	ht := (1-t)*cs.H + t*ce.H // Will never cross 1:0
-	st := (1-t)*cs.S + t*ce.S
-	lt := (1-t)*cs.L + t*ce.L
-	at := (1-t)*cs.A + t*ce.A
-	return g2dcol.HSL{ht, st, lt, at}
-}
-
-// ColorHSLLerpS calculates the color value at t [0,1] given a start and end color in HSL space.
-// Differs from ColorHSLLerp in that the shortest path for hue is taken.
-func ColorHSLLerpS(t float64, start, end color.Color) color.Color {
-	cs, ce := g2dcol.NewHSL(start), g2dcol.NewHSL(end)
-	hd := ce.H - cs.H
-	ht := 0.0
-	// Handle hue being circular
-	if hd > 0.5 || hd < -0.5 {
-		h := ce.H - 1
-		ht = (1-t)*cs.H + t*h
-		if ht < 0 {
-			ht += 1
-		}
-	} else {
-		ht = (1-t)*cs.H + t*ce.H
-	}
-	st := (1-t)*cs.S + t*ce.S
-	lt := (1-t)*cs.L + t*ce.L
-	at := (1-t)*cs.A + t*ce.A
-	return g2dcol.HSL{ht, st, lt, at}
+	c1 := g2dcol.ColorRGBALerp(v, colors[0], colors[2])
+	c2 := g2dcol.ColorRGBALerp(v, colors[1], colors[3])
+	return g2dcol.ColorRGBALerp(u, c1, c2)
 }