// Copyright (c) 2005, Niels Martin Hansen, Rodrigo Braz Monteiro // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // * Redistributions of source code must retain the above copyright notice, // this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above copyright notice, // this list of conditions and the following disclaimer in the documentation // and/or other materials provided with the distribution. // * Neither the name of the Aegisub Group nor the names of its contributors // may be used to endorse or promote products derived from this software // without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE // POSSIBILITY OF SUCH DAMAGE. // // Aegisub Project http://www.aegisub.org/ /// @file colorspace.cpp /// @brief Functions for converting colours between different representations /// @ingroup utility /// #include "colorspace.h" #include "utils.h" static inline unsigned int clip_colorval(int val) { return mid(0, val, 255); } // Algorithm from http://130.113.54.154/~monger/hsl-rgb.html void hsl_to_rgb(int H, int S, int L, unsigned char *R, unsigned char *G, unsigned char *B) { if (S == 0) { *R = L; *G = L; *B = L; return; } if (L == 128 && S == 255) { switch (H) { case 0: case 255: // actually this is wrong, since this is more like 359 degrees... but it's what you'd expect (sadly :) *R = 255; *G = 0; *B = 0; return; case 43: *R = 255; *G = 255; *B = 0; return; case 85: *R = 0; *G = 255; *B = 0; return; case 128: *R = 0; *G = 255; *B = 255; return; case 171: *R = 0; *G = 0; *B = 255; return; case 213: *R = 255; *G = 0; *B = 255; return; } } float h, s, l, r, g, b; h = H / 255.f; s = S / 255.f; l = L / 255.f; float temp2; if (l < .5f) { temp2 = l * (1.f + s); } else { temp2 = l + s - l*s; } float temp1 = 2.f * l - temp2; // assume h is in range [0;1] float temp3[3]; temp3[0] = h + 1.f/3.f; if (temp3[0] > 1.f) temp3[0] -= 1.f; temp3[1] = h; temp3[2] = h - 1.f/3.f; if (temp3[2] < 0.f) temp3[2] += 1.f; if (6.f * temp3[0] < 1.f) r = temp1 + (temp2 - temp1) * 6.f * temp3[0]; else if (2.f * temp3[0] < 1.f) r = temp2; else if (3.f * temp3[0] < 2.f) r = temp1 + (temp2 - temp1) * ((2.f/3.f) - temp3[0]) * 6.f; else r = temp1; if (6.f * temp3[1] < 1.f) g = temp1 + (temp2 - temp1) * 6.f * temp3[1]; else if (2.f * temp3[1] < 1.f) g = temp2; else if (3.f * temp3[1] < 2.f) g = temp1 + (temp2 - temp1) * ((2.f/3.f) - temp3[1]) * 6.f; else g = temp1; if (6.f * temp3[2] < 1.f) b = temp1 + (temp2 - temp1) * 6.f * temp3[2]; else if (2.f * temp3[2] < 1.f) b = temp2; else if (3.f * temp3[2] < 2.f) b = temp1 + (temp2 - temp1) * ((2.f/3.f) - temp3[2]) * 6.f; else b = temp1; *R = clip_colorval((int)(r*255)); *G = clip_colorval((int)(g*255)); *B = clip_colorval((int)(b*255)); } // Formulas taken from wikipedia: http://en.wikipedia.org/wiki/HSV_color_space // The range for H is 0..255 instead of 0..359, so 60 degrees has been translated to 256/6 here void hsv_to_rgb(int H, int S, int V, unsigned char *R, unsigned char *G, unsigned char *B) { *R = *G = *B = 0; // some special cases... oh yeah baby! if (S == 255) { switch (H) { case 0: case 255: // actually this is wrong, since this is more like 359 degrees... but it's what you'd expect (sadly :) *R = V; *G = 0; *B = 0; return; case 43: *R = V; *G = V; *B = 0; return; case 85: *R = 0; *G = V; *B = 0; return; case 128: *R = 0; *G = V; *B = V; return; case 171: *R = 0; *G = 0; *B = V; return; case 213: *R = V; *G = 0; *B = V; return; } } // Cap values unsigned int h = H * 360; unsigned int s = clip_colorval(S)*256; unsigned int v = clip_colorval(V)*256; // Saturation is zero, make grey if (S == 0) { *R = V; *G = V; *B = V; return; } unsigned int r, g, b; // Else, calculate color unsigned int Hi = h / 60 / 256; unsigned int f = h / 60 - Hi * 256; unsigned int p = v * (65535 - s) / 65536; unsigned int q = v * (65535 - (f * s)/256) / 65536; unsigned int t = v * (65535 - ((255 - f) * s)/256) / 65536; switch (Hi) { case 0: r = v; g = t; b = p; break; case 1: r = q; g = v; b = p; break; case 2: r = p; g = v; b = t; break; case 3: r = p; g = q; b = v; break; case 4: r = t; g = p; b = v; break; case 5: default: r = v; g = p; b = q; break; } *R = clip_colorval(r/256); *G = clip_colorval(g/256); *B = clip_colorval(b/256); } /// Algorithm from http://130.113.54.154/~monger/hsl-rgb.html void rgb_to_hsl(int R, int G, int B, unsigned char *H, unsigned char *S, unsigned char *L) { float r = R/255.f, g = G/255.f, b = B/255.f; float h, s, l; float maxrgb = std::max(r, std::max(g, b)), minrgb = std::min(r, std::min(g, b)); l = (minrgb + maxrgb) / 2; if (minrgb == maxrgb) { h = 0; s = 0; } else { if (l < .5f) { s = (maxrgb - minrgb) / (maxrgb + minrgb); } else { s = (maxrgb - minrgb) / (2.f - maxrgb - minrgb); } if (r == maxrgb) { h = (g-b) / (maxrgb-minrgb) + 0; } else if (g == maxrgb) { h = (b-r) / (maxrgb-minrgb) + 2; } else { // if b == maxrgb h = (r-g) / (maxrgb-minrgb) + 4; } } if (h < 0) h += 6; if (h >= 6) h -= 6; *H = clip_colorval(int(h*256/6)); *S = clip_colorval(int(s*255)); *L = clip_colorval(int(l*255)); } /// Formulas from http://en.wikipedia.org/wiki/HSV_color_space void rgb_to_hsv(int R, int G, int B, unsigned char *H, unsigned char *S, unsigned char *V) { float r = R/255.f, g = G/255.f, b = B/255.f; float h, s, v; float maxrgb = std::max(r, std::max(g, b)), minrgb = std::min(r, std::min(g, b)); v = maxrgb; if (maxrgb < .001f) { s = 1; } else { s = (maxrgb - minrgb) / maxrgb; } if (minrgb == maxrgb) { h = 0; } else if (maxrgb == r) { h = (g-b) / (maxrgb-minrgb) + 0; } else if (maxrgb == g) { h = (b-r) / (maxrgb-minrgb) + 2; } else { // if maxrgb == b h = (r-g) / (maxrgb-minrgb) + 4; } if (h < 0) h += 6; if (h >= 6) h -= 6; *H = clip_colorval(int(h*256/6)); *S = clip_colorval(int(s*255)); *V = clip_colorval(int(v*255)); } void hsv_to_hsl(int iH, int iS, int iV, unsigned char *oH, unsigned char *oS, unsigned char *oL) { int p = iV * (255 - iS); *oH = iH; *oL = clip_colorval((p + iV*255)/255/2); if (*oL == 0) { *oS = iS; // oS is actually undefined, so any value should work ;) } else if (*oL <= 128) { *oS = clip_colorval((iV*255 - p) / (2 * *oL)); } else { *oS = clip_colorval((iV*255 - p) / (511 - 2 * *oL)); } } void hsl_to_hsv(int iH, int iS, int iL, unsigned char *oH, unsigned char *oS, unsigned char *oV) { *oH = iH; if (iS == 0) { *oS = 0; *oV = iL; return; } if (iL < 128) { *oV = iL * (255 + iS) / 255; *oS = 2 * 255 * iS / (255 + iS); } else { *oV = (iL*255 + iS*255 - iL*iS)/255; *oS = 2 * 255 * iS * (255 - iL) / (iL*255 + iS*255 - iL*iS); } }