Configurable palette

internal/gopow/palette.go

@@ -0,0 +1,61 @@
+package gopow
+
+import (
+	"image/color"
+
+	"github.com/lucasb-eyer/go-colorful"
+)
+
+type Palette interface {
+	ColorAt(table *TableComplex, x, y int) color.Color
+}
+
+type YellowPalette struct {
+}
+
+func (p *YellowPalette) ColorAt(table *TableComplex, x, y int) color.Color {
+	cell := table.Rows[y].Sample(x)
+
+	hueStart := 0.0
+	hueEnd := 1.0
+
+	span := (*table.Config.MinPower - *table.Config.MaxPower) * -1
+	hPerDeg := (hueStart - hueEnd) / span
+	powNormalized := cell - *table.Config.MinPower
+	powDegrees := powNormalized * hPerDeg
+	hue := hueStart - powDegrees
+
+	if hue < hueStart {
+		hue = hueStart
+	}
+	if hue > hueEnd {
+		hue = hueEnd
+	}
+
+	return colorful.Color{hue, hue, 0}
+}
+
+type SpectrumPalette struct {
+}
+
+func (p *SpectrumPalette) ColorAt(table *TableComplex, x, y int) color.Color {
+	cell := table.Rows[y].Sample(x)
+
+	hueStart := 236.0
+	hueEnd := 0.0
+
+	span := (*table.Config.MinPower - *table.Config.MaxPower) * -1
+	hPerDeg := (hueStart - hueEnd) / span
+	powNormalized := cell - *table.Config.MinPower
+	powDegrees := powNormalized * hPerDeg
+	hue := hueStart - powDegrees
+
+	if hue > hueStart {
+		hue = hueStart
+	}
+	if hue < hueEnd {
+		hue = hueEnd
+	}
+
+	return colorful.Hsv(hue, 1, 0.90)
+}