sixel_hls.c (2860B)
1 // sixel.c (part of mintty) 2 // this function is derived from a part of graphics.c 3 // in Xterm pl#310 originally written by Ross Combs. 4 // 5 // Copyright 2013,2014 by Ross Combs 6 // 7 // All Rights Reserved 8 // 9 // Permission is hereby granted, free of charge, to any person obtaining a 10 // copy of this software and associated documentation files (the 11 // "Software"), to deal in the Software without restriction, including 12 // without limitation the rights to use, copy, modify, merge, publish, 13 // distribute, sublicense, and/or sell copies of the Software, and to 14 // permit persons to whom the Software is furnished to do so, subject to 15 // the following conditions: 16 // 17 // The above copyright notice and this permission notice shall be included 18 // in all copies or substantial portions of the Software. 19 // 20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 21 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 23 // IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 24 // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 25 // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 26 // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 27 // 28 // Except as contained in this notice, the name(s) of the above copyright 29 // holders shall not be used in advertising or otherwise to promote the 30 // sale, use or other dealings in this Software without prior written 31 // authorization. 32 33 #define SIXEL_RGB(r, g, b) ((255 << 24) + ((r) << 16) + ((g) << 8) + (b)) 34 35 int 36 hls_to_rgb(int hue, int lum, int sat) 37 { 38 double lv = lum / 100.0; 39 double sv = sat / 100.0; 40 double c, x, m, c2; 41 double r1, g1, b1; 42 int r, g, b, hs; 43 44 hue = (hue + 240) % 360; 45 if (sat == 0) { 46 r = g = b = lum * 255 / 100; 47 return SIXEL_RGB(r, g, b); 48 } 49 50 if ((c2 = ((2.0 * lv) - 1.0)) < 0.0) { 51 c2 = -c2; 52 } 53 if ((hs = (hue % 120) - 60) < 0) { 54 hs = -hs; 55 } 56 c = (1.0 - c2) * sv; 57 x = ((60 - hs) / 60.0) * c; 58 m = lv - 0.5 * c; 59 60 switch (hue / 60) { 61 case 0: 62 r1 = c; 63 g1 = x; 64 b1 = 0.0; 65 break; 66 case 1: 67 r1 = x; 68 g1 = c; 69 b1 = 0.0; 70 break; 71 case 2: 72 r1 = 0.0; 73 g1 = c; 74 b1 = x; 75 break; 76 case 3: 77 r1 = 0.0; 78 g1 = x; 79 b1 = c; 80 break; 81 case 4: 82 r1 = x; 83 g1 = 0.0; 84 b1 = c; 85 break; 86 case 5: 87 r1 = c; 88 g1 = 0.0; 89 b1 = x; 90 break; 91 default: 92 return SIXEL_RGB(255, 255, 255); 93 } 94 95 r = (int) ((r1 + m) * 255.0 + 0.5); 96 g = (int) ((g1 + m) * 255.0 + 0.5); 97 b = (int) ((b1 + m) * 255.0 + 0.5); 98 99 if (r < 0) { 100 r = 0; 101 } else if (r > 255) { 102 r = 255; 103 } 104 if (g < 0) { 105 g = 0; 106 } else if (g > 255) { 107 g = 255; 108 } 109 if (b < 0) { 110 b = 0; 111 } else if (b > 255) { 112 b = 255; 113 } 114 return SIXEL_RGB(r, g, b); 115 }