1 package edu.jiangxin.apktoolbox.convert.color.colorspace;
2
3 import java.awt.color.ColorSpace;
4
5 public class HslColorSpace extends ColorSpace {
6
7 protected HslColorSpace(int type, int numComponents) {
8 super(type, numComponents);
9 }
10
11 public static HslColorSpace getInstance() {
12 return Holder.INSTANCE;
13 }
14
15 @Override
16 public float[] toRGB(float[] colorvalue) {
17 float h = colorvalue[0];
18 float s = colorvalue[1];
19 float l = colorvalue[2];
20
21 float r, g, b;
22
23 if (s == 0f) {
24 r = g = b = l;
25 } else {
26 float q = l < 0.5f ? l * (1 + s) : l + s - l * s;
27 float p = 2 * l - q;
28 r = hueToRgb(p, q, h + 1/3f);
29 g = hueToRgb(p, q, h);
30 b = hueToRgb(p, q, h - 1/3f);
31 }
32
33 return new float[]{r, g, b};
34 }
35
36 @Override
37 public float[] fromRGB(float[] rgbvalue) {
38 float r = rgbvalue[0];
39 float g = rgbvalue[1];
40 float b = rgbvalue[2];
41
42 float max = Math.max(r, Math.max(g, b));
43 float min = Math.min(r, Math.min(g, b));
44
45 float h, s;
46 float l = (max + min) / 2;
47
48 if (max == min) {
49 h = s = 0f;
50 } else {
51 float delta = max - min;
52 s = l > 0.5f ? delta / (2 - max - min) : delta / (max + min);
53 if (max == r) {
54 h = (g - b) / delta + (g < b ? 6f : 0f);
55 } else if (max == g) {
56 h = (b - r) / delta + 2f;
57 } else {
58 h = (r - g) / delta + 4f;
59 }
60 h /= 6f;
61 }
62
63 return new float[]{h, s, l};
64 }
65
66 @Override
67 public float[] toCIEXYZ(float[] colorvalue) {
68 float[] rgb = toRGB(colorvalue);
69 return ColorSpace.getInstance(CS_sRGB).toCIEXYZ(rgb);
70 }
71
72 @Override
73 public float[] fromCIEXYZ(float[] colorvalue) {
74 float[] rgb = ColorSpace.getInstance(CS_sRGB).fromCIEXYZ(colorvalue);
75 return fromRGB(rgb);
76 }
77
78 private float hueToRgb(float p, float q, float t) {
79 if (t < 0f) t += 1f;
80 if (t > 1f) t -= 1f;
81 if (t < 1/6f) return p + (q - p) * 6f * t;
82 if (t < 1/2f) return q;
83 if (t < 2/3f) return p + (q - p) * (2/3f - t) * 6f;
84 return p;
85 }
86
87 private static class Holder {
88 private static final HslColorSpace INSTANCE = new HslColorSpace(TYPE_HLS, 3);
89 }
90 }