colorMap.go

package main

import (
	"log"
	"math"
)

type colorPoint struct {
	position float64
	red      float64
	green    float64
	blue     float64
}

func makeColorPalette(controlColors []colorPoint, numColors int) []colorPoint {

	colorsPerPosition := numColors / 100.0
	lastPoint := controlColors[0]
	//If first control color is not at 0 then copy color for range
	lastIndexFilled := 0
	outColors := make([]colorPoint, numColors)
	outColors[0].red = math.Round(controlColors[0].red * 255.0 / 100.0)
	outColors[0].blue = math.Round(controlColors[0].blue * 255.0 / 100.0)
	outColors[0].green = math.Round(controlColors[0].green * 255.0 / 100.0)
	for i := 1; i < len(controlColors); i++ {
		//possDiff:=controlColors[i].position-lastPoint.position
		redDiff := (float64(controlColors[i].red) - float64(lastPoint.red)) * 255.0 / 100
		greenDiff := (float64(controlColors[i].green) - float64(lastPoint.green)) * 255.0 / 100
		blueDiff := (float64(controlColors[i].blue) - float64(lastPoint.blue)) * 255.0 / 100
		startRange := lastIndexFilled + 1
		endRange := int(math.Round(float64(controlColors[i].position) * float64(colorsPerPosition)))
		for j := startRange; j < endRange; j++ {

			percentRange := (float64(j+1) - float64(startRange)) / float64((endRange - startRange))
			outColors[j].red = (math.Round(percentRange*redDiff + float64(lastPoint.red)*255.0/100))
			outColors[j].green = (math.Round(percentRange*greenDiff + float64(lastPoint.green)*255.0/100))
			outColors[j].blue = (math.Round(percentRange*blueDiff + float64(lastPoint.blue)*255.0/100))
			outColors[j].position = float64(j)
			lastIndexFilled = j
		}
		lastPoint = controlColors[i]

	}
	return outColors
}

func getColorConrolPoints(colorMap string) []colorPoint {
	var outColors []colorPoint
	switch colorMap {
	case "Greyscale":
		outColors = make([]colorPoint, 3)
		outColors[0] = colorPoint{0, 0, 0, 0}
		outColors[1] = colorPoint{60, 50, 50, 50}
		outColors[2] = colorPoint{100, 100, 100, 100}
	case "Ramp Colormap":
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 0, 0, 15}
		outColors[1] = colorPoint{10, 0, 0, 50}
		outColors[2] = colorPoint{31, 0, 65, 75}
		outColors[3] = colorPoint{50, 0, 80, 0}
		outColors[4] = colorPoint{70, 75, 80, 0}
		outColors[5] = colorPoint{83, 100, 60, 0}
		outColors[6] = colorPoint{100, 100, 0, 0}
	case "Color Wheel":
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 100, 100, 0}
		outColors[1] = colorPoint{20, 0, 80, 40}
		outColors[2] = colorPoint{30, 0, 100, 100}
		outColors[3] = colorPoint{50, 10, 10, 0}
		outColors[4] = colorPoint{65, 100, 0, 0}
		outColors[5] = colorPoint{88, 100, 40, 0}
		outColors[6] = colorPoint{100, 100, 100, 0}
	case "Spectrum":
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 0, 75, 0}
		outColors[1] = colorPoint{22, 0, 90, 90}
		outColors[2] = colorPoint{37, 0, 0, 85}
		outColors[3] = colorPoint{49, 90, 0, 85}
		outColors[4] = colorPoint{68, 90, 0, 0}
		outColors[5] = colorPoint{80, 90, 90, 0}
		outColors[6] = colorPoint{100, 95, 95, 95}
	case "calewhite":
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 100, 100, 100}
		outColors[1] = colorPoint{16.666, 0, 0, 100}
		outColors[2] = colorPoint{33.333, 0, 100, 100}
		outColors[3] = colorPoint{50, 0, 100, 0}
		outColors[4] = colorPoint{66.666, 100, 100, 0}
		outColors[5] = colorPoint{83.333, 100, 0, 0}
		outColors[6] = colorPoint{100, 100, 0, 100}
	case "HotDesat":
		outColors = make([]colorPoint, 8)
		outColors[0] = colorPoint{0, 27.84, 27.84, 85.88}
		outColors[1] = colorPoint{14.2857, 0, 0, 35.69}
		outColors[2] = colorPoint{28.571, 0, 100, 100}
		outColors[3] = colorPoint{42.857, 0, 49.8, 0}
		outColors[4] = colorPoint{57.14286, 100, 100, 0}
		outColors[5] = colorPoint{71.42857, 100, 37.65, 0}
		outColors[6] = colorPoint{85.7143, 41.96, 0, 0}
		outColors[7] = colorPoint{100, 87.84, 29.8, 29.8}
	case "Sunset":
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 10, 0, 23}
		outColors[1] = colorPoint{18, 34, 0, 60}
		outColors[2] = colorPoint{36, 58, 20, 47}
		outColors[3] = colorPoint{55, 74, 20, 28}
		outColors[4] = colorPoint{72, 90, 43, 0}
		outColors[5] = colorPoint{87, 100, 72, 0}
		outColors[6] = colorPoint{100, 100, 100, 76}
	default:
		log.Println("Unknown Colormap", colorMap, "using default RampColormap")
		outColors = make([]colorPoint, 7)
		outColors[0] = colorPoint{0, 0, 0, 15}
		outColors[1] = colorPoint{10, 0, 0, 50}
		outColors[2] = colorPoint{31, 0, 65, 75}
		outColors[3] = colorPoint{50, 0, 80, 0}
		outColors[4] = colorPoint{70, 75, 80, 0}
		outColors[5] = colorPoint{83, 100, 60, 0}
		outColors[6] = colorPoint{100, 100, 0, 0}
	}
	return outColors
}