add gradient and random effect.

internal/color/color.go

@@ -188,11 +188,17 @@ func (col *Color) Interpolate(other Color, fac float64) Color {
 		return Color{K: &k3}
 	}
 
+	if fac < 0.000001 {
+		return *col
+	} else if fac > 0.999999 {
+		return other
+	}
+
 	// Get the colorful values.
 	cvCF := col.colorful()
 	otherCF := other.colorful()
 
-	// Blend and normalize
+	// Blend and normalize (clamping is hax to avoid issues with some colors)
 	blended := cvCF.BlendLuv(otherCF, fac)
 	blendedHue, blendedSat, _ := blended.Hsv()
 	blendedHs := HueSat{Hue: blendedHue, Sat: blendedSat}
@@ -253,7 +259,7 @@ func (col *Color) colorful() colorful.Color {
 	case col.XY != nil:
 		return colorful.Xyy(col.XY.X, col.XY.Y, 0.5)
 	default:
-		return colorful.Color{R: 255, B: 255, G: 255}
+		return colorful.Color{R: 1, B: 1, G: 1}
 	}
 }
 

internal/color/hs.go

@@ -1,6 +1,9 @@
 package color
 
-import "github.com/lucasb-eyer/go-colorful"
+import (
+	"github.com/lucasb-eyer/go-colorful"
+	"math"
+)
 
 type HueSat struct {
 	Hue float64 `json:"hue"`
@@ -13,5 +16,5 @@ func (hs HueSat) ToXY() XY {
 
 func (hs HueSat) ToRGB() RGB {
 	c := colorful.Hsv(hs.Hue, hs.Sat, 1)
-	return RGB{Red: c.R, Green: c.G, Blue: c.B}
+	return RGB{Red: math.Max(c.R, 0), Green: math.Max(c.G, 0), Blue: math.Max(c.B, 0)}
 }

internal/color/rgb.go

@@ -14,6 +14,14 @@ func (rgb RGB) AtIntensity(intensity float64) RGB {
 	return RGB{Red: hsv2.R, Green: hsv2.G, Blue: hsv2.B}
 }
 
+func (rgb RGB) Bytes() [3]uint8 {
+	return [3]uint8{
+		uint8(rgb.Red * 255.0),
+		uint8(rgb.Green * 255.0),
+		uint8(rgb.Blue * 255.0),
+	}
+}
+
 func (rgb RGB) ToHS() HueSat {
 	hue, sat, _ := colorful.Color{R: rgb.Red, G: rgb.Green, B: rgb.Blue}.Hsv()
 	return HueSat{Hue: hue, Sat: sat}