Gabriele Cosmo
112 lines
2.4 KiB
Plaintext
112 lines
2.4 KiB
Plaintext
// Copyright (C) 2010, Guy Barrand. All rights reserved.
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// See the file tools.license for terms.
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#ifndef tools_hls
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#define tools_hls
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namespace tools {
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//T is float or double.
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template <class T>
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inline T hls_to_rgb2(T rn1,T rn2,T huei) {
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// taken from CERN-ROOT/TColor.
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T hue = huei;
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if (hue > 360) hue = hue - 360;
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if (hue < 0) hue = hue + 360;
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if (hue < 60 ) return rn1 + (rn2-rn1)*hue/60;
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if (hue < 180) return rn2;
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if (hue < 240) return rn1 + (rn2-rn1)*(240-hue)/60;
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return rn1;
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}
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template <class T>
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inline void hls_to_rgb(T hue,T light,T satur,T& a_r,T& a_g,T& a_b){
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// taken from CERN-ROOT/TColor.
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// Static method to compute RGB from HLS. The l and s are between [0,1]
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// and h is between [0,360]. The returned r,g,b triplet is between [0,1].
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T rh, rl, rs, rm1, rm2;
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rh = rl = rs = 0;
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if (hue > 0) rh = hue;
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if (rh > 360) rh = 360;
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if (light > 0) rl = light;
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if (rl > 1) rl = 1;
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if (satur > 0) rs = satur;
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if (rs > 1) rs = 1;
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if (rl <= T(0.5)) {
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rm2 = rl*(1 + rs);
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} else {
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rm2 = rl + rs - rl*rs;
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}
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rm1 = 2*rl - rm2;
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if (!rs) { a_r = rl; a_g = rl; a_b = rl; return; }
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a_r = hls_to_rgb2(rm1, rm2, rh+120);
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a_g = hls_to_rgb2(rm1, rm2, rh);
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a_b = hls_to_rgb2(rm1, rm2, rh-120);
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}
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template <class T>
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inline void rgb_to_hls(T rr,T gg,T bb,T& hue,T& light,T& satur) {
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// The r,g,b triplet is between
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// [0,1], hue is between [0,360], light and satur are [0,1].
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T rnorm, gnorm, bnorm, minval, maxval, msum, mdiff, cr, cg, cb;
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minval = maxval = 0;
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cr = cg = cb = 0;
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if (rr > 0) cr = rr;
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if (cr > 1) cr = 1;
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if (gg > 0) cg = gg;
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if (cg > 1) cg = 1;
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if (bb > 0) cb = bb;
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if (cb > 1) cb = 1;
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minval = cr;
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if (cg < minval) minval = cg;
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if (cb < minval) minval = cb;
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maxval = cr;
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if (cg > maxval) maxval = cg;
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if (cb > maxval) maxval = cb;
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rnorm = gnorm = bnorm = 0;
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mdiff = maxval - minval;
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msum = maxval + minval;
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light = T(0.5) * msum;
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if (maxval != minval) {
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rnorm = (maxval - cr)/mdiff;
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gnorm = (maxval - cg)/mdiff;
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bnorm = (maxval - cb)/mdiff;
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} else {
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satur = hue = 0;
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return;
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}
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if (light < T(0.5))
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satur = mdiff/msum;
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else
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satur = mdiff/(2 - msum);
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if (cr == maxval)
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hue = 60 * (6 + bnorm - gnorm);
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else if (cg == maxval)
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hue = 60 * (2 + rnorm - bnorm);
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else
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hue = 60 * (4 + gnorm - rnorm);
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if (hue > 360)
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hue = hue - 360;
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}
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}
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#endif
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