Colors.cpp

00001 #include <math.h>
00002 #include <mbed.h>
00003 #include "Colors.h"
00004 
00005 void HSBtoRGB(float hue, float saturation, float brightness, uint8_t *pr, uint8_t *pg, uint8_t *pb)
00006 {
00007     uint8_t r = 0, g = 0, b = 0;
00008     if (saturation == 0) {
00009         r = g = b = (uint8_t) (brightness * 255.0f + 0.5f);
00010     } else {
00011         float h = (hue - (float)floor(hue)) * 6.0f;
00012         float f = h - (float)floor(h);
00013         float p = brightness * (1.0f - saturation);
00014         float q = brightness * (1.0f - saturation * f);
00015         float t = brightness * (1.0f - (saturation * (1.0f - f)));
00016         switch ((int) h) {
00017             case 0:
00018                 r = (int) (brightness * 255.0f + 0.5f);
00019                 g = (int) (t * 255.0f + 0.5f);
00020                 b = (int) (p * 255.0f + 0.5f);
00021                 break;
00022             case 1:
00023                 r = (int) (q * 255.0f + 0.5f);
00024                 g = (int) (brightness * 255.0f + 0.5f);
00025                 b = (int) (p * 255.0f + 0.5f);
00026                 break;
00027             case 2:
00028                 r = (int) (p * 255.0f + 0.5f);
00029                 g = (int) (brightness * 255.0f + 0.5f);
00030                 b = (int) (t * 255.0f + 0.5f);
00031                 break;
00032             case 3:
00033                 r = (int) (p * 255.0f + 0.5f);
00034                 g = (int) (q * 255.0f + 0.5f);
00035                 b = (int) (brightness * 255.0f + 0.5f);
00036                 break;
00037             case 4:
00038                 r = (int) (t * 255.0f + 0.5f);
00039                 g = (int) (p * 255.0f + 0.5f);
00040                 b = (int) (brightness * 255.0f + 0.5f);
00041                 break;
00042             case 5:
00043                 r = (int) (brightness * 255.0f + 0.5f);
00044                 g = (int) (p * 255.0f + 0.5f);
00045                 b = (int) (q * 255.0f + 0.5f);
00046                 break;
00047         }
00048     }
00049     *pr = r;
00050     *pg = g;
00051     *pb = b;
00052 }
00053 
00054 float* RGBtoHSB(uint8_t r, uint8_t g, uint8_t b, float* hsbvals)
00055 {
00056     float hue, saturation, brightness;
00057     if (!hsbvals) {
00058         hsbvals = new float[3];
00059     }
00060     uint8_t cmax = (r > g) ? r : g;
00061     if (b > cmax) cmax = b;
00062     uint8_t cmin = (r < g) ? r : g;
00063     if (b < cmin) cmin = b;
00064 
00065     brightness = ((float) cmax) / 255.0f;
00066     if (cmax != 0)
00067         saturation = ((float) (cmax - cmin)) / ((float) cmax);
00068     else
00069         saturation = 0;
00070     if (saturation == 0)
00071         hue = 0;
00072     else {
00073         float redc = ((float) (cmax - r)) / ((float) (cmax - cmin));
00074         float greenc = ((float) (cmax - g)) / ((float) (cmax - cmin));
00075         float bluec = ((float) (cmax - b)) / ((float) (cmax - cmin));
00076         if (r == cmax)
00077             hue = bluec - greenc;
00078         else if (g == cmax)
00079             hue = 2.0f + redc - bluec;
00080         else
00081             hue = 4.0f + greenc - redc;
00082         hue = hue / 6.0f;
00083         if (hue < 0)
00084             hue = hue + 1.0f;
00085     }
00086     hsbvals[0] = hue;
00087     hsbvals[1] = saturation;
00088     hsbvals[2] = brightness;
00089     return hsbvals;
00090 }