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SVG SUBSET C++ API
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a60-svg-color.h
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1// svg color -*- mode: C++ -*-
2
3// Copyright (C) 2014-2025 Benjamin De Kosnik <b.dekosnik@gmail.com>
4
5// This file is part of the alpha60-MiL SVG library. This library is
6// free software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the Free
8// Software Foundation; either version 3, or (at your option) any
9// later version.
10
11// This library is distributed in the hope that it will be useful, but
12// WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14// General Public License for more details.
15
16#ifndef MiL_SVG_COLOR_H
17#define MiL_SVG_COLOR_H 1
18
19#include <map>
20#include <algorithm>
21#include <random>
22#include <iomanip>
23
24
25namespace svg {
26
27/**
28 HUE
29
30 color = color enum (and name string conversion)
31
32 color_qi = color quantified as RGB integral values 0-255
33 (similar to Scalar in OpenCV).
34
35 color_qf = color quantified as Hue Saturation Value (HSV) decimal values 0-1
36
37 spectrum = color spectrum as finite array of color enum values
38*/
39
40/// Color enumerated as types.
41enum class color
42{
43 none,
44
45 // 21 tints / shades
46 white,
47 black,
48 gray01,
49 gray02,
50 gray05,
51 gray10,
52 gray20,
53 gray25, // gainsboro
54 gray30,
55 gray33,
56 gray40,
57 gray50,
58 gray60,
59 gray66,
60 gray75, // slategray
61 gray70,
62 gray80,
63 gray90,
64
65 wcag_lgray,
66 wcag_gray,
67 wcag_dgray,
68
69 // 15 yellow
70 kanzoiro, // daylily light orange
71 kohakuiro, // amber
72 kinsusutake, // golden-gray bamoo
73 daylily,
74 goldenyellow,
75 hellayellow,
76 antiquewhite,
77 lemonchiffon,
78 goldenrod,
79 navajowhite,
80 ivory,
81 gold,
82 duboisyellow1,
83 duboisyellow2,
84 duboisyellow3,
85
86 // 7 orange
87 orange,
88 darkorange,
89 asamaorange,
90 redorange,
91 orangered,
92 dutchorange,
93 internationalorange,
94
95 // 17 red
96 red,
97 foreigncrimson, // red
98 ginshu, // gray red
99 akabeni, // pure crimson
100 akebonoiro, // dawn color
101 ochre,
102 sohi,
103 benikaba, // red birch
104 benitobi, // red kite bird
105 ake, // scarlet/blood
106 crimson,
107 tomato,
108 coral,
109 salmon,
110 duboisred1,
111 duboisred2,
112 duboisred3,
113
114 // 4 brown
115 duboisbrown1,
116 duboisbrown2,
117 duboisbrown3,
118 duboisbrown4,
119 duboisbrown5,
120
121 // 20 green
122 byakuroku, // whitish green
123 usumoegi, // pale onion
124 moegi, // onion green
125 hiwamoegi, // siskin sprout
126 midori,
127 rokusho,
128 aotakeiro, // green bamboo
129 seiheki, // blue green
130 seijiiro, // celadon
131 yanagizome, // willow dye
132 green,
133 chartreuse,
134 greenyellow,
135 limegreen,
136 springgreen,
137 aquamarine,
138 duboisgreen1,
139 duboisgreen2,
140 duboisgreen3,
141 duboisgreen4,
142 duboisgreen5,
143
144 // 35 blue
145 blue,
146 ultramarine,
147 shinbashiiro,
148 hanada, // blue silk
149 ruriiro, // lapis
150 bellflower,
151 navy,
152 asagiiro, // light blue
153 indigo,
154 rurikon, // dark blue lapis
155 asamablue,
156 cyan,
157 lightcyan,
158 powderblue,
159 steelblue,
160 cornflowerblue,
161 deepskyblue,
162 dodgerblue,
163 lightblue,
164 skyblue,
165 lightskyblue,
166 midnightblue,
167 mediumblue,
168 royalblue,
169 darkslateblue,
170 slateblue,
171 azure,
172 crayolacerulean,
173 duboisblue1,
174 duboisblue2,
175 duboisblue3,
176 duboisblue4,
177 blueprintlight,
178 blueprint,
179 blueprintdark,
180
181 // 32 purple
182 wisteria,
183 murasaki, // purple
184 ayameiro,
185 peony,
186 futaai, // dark indigo
187 benimidori, // stained red/violet
188 redwisteria, // dusty rose
189 botan, // tree peony
190 kokimurasaki, // deep purple
191 usuiro, // thin
192 asamapink,
193 blueviolet,
194 darkmagenta,
195 darkviolet,
196 thistle,
197 plum,
198 violet,
199 magenta,
200 dfuschia,
201 deeppink,
202 hotpink,
203 pink,
204 kissmepink,
205 palevioletred,
206 mediumvioletred,
207 lavender,
208 orchid,
209 mediumorchid,
210 darkestmagenta,
211 mediumpurple,
212 purple,
213 dustyrose,
214 atmosphericp,
215
216 // STOS
217 command,
218 science,
219 engineering,
220
221 // Must be last, so can be cast to int for size.
222 last
223};
224
225/// Total number of enumerated colors.
226constexpr uint color_max_size = static_cast<uint>(color::last);
227
228/// Convert color to RGB color value string.
229const std::string&
230to_string(const color e)
231{
232 using enum_map_type = std::map<color, std::string>;
233
234 static enum_map_type enum_map;
235 if (enum_map.empty())
236 {
237 enum_map[color::white] = "rgb(255, 255, 255)";
238 enum_map[color::black] = "rgb(0, 0, 0)";
239 enum_map[color::gray90] = "rgb(25, 25, 25)";
240 enum_map[color::gray80] = "rgb(50, 50, 50)";
241 enum_map[color::gray75] = "rgb(64, 64, 64)";
242 enum_map[color::gray70] = "rgb(77, 77, 77)";
243 enum_map[color::gray66] = "rgb(87, 87, 87)";
244 enum_map[color::gray60] = "rgb(100, 100, 100)";
245 enum_map[color::gray50] = "rgb(128, 128, 128)";
246 enum_map[color::gray40] = "rgb(150, 150, 150)";
247 enum_map[color::gray30] = "rgb(180, 180, 180)";
248 enum_map[color::gray33] = "rgb(171, 171, 171)";
249 enum_map[color::gray25] = "rgb(191, 191, 191)";
250 enum_map[color::gray20] = "rgb(200, 200, 200)";
251 enum_map[color::gray10] = "rgb(230, 230, 230)";
252 enum_map[color::gray05] = "rgb(242, 242, 242)";
253 enum_map[color::gray02] = "rgb(248, 248, 248)";
254 enum_map[color::gray01] = "rgb(252, 252, 252)";
255
256 enum_map[color::wcag_lgray] = "rgb(148, 148, 148)"; // LG TXT on white 3:1
257 enum_map[color::wcag_gray] = "rgb(118, 118, 118)"; // min on white 4.5:1
258 enum_map[color::wcag_dgray] = "rgb(46, 46, 46)"; // on white 13.6:1
259
260 enum_map[color::command] = "rgb(255, 0, 171)";
261 enum_map[color::science] = "rgb(150, 230, 191)";
262 enum_map[color::engineering] = "rgb(161, 158, 178)";
263
264 enum_map[color::kissmepink] = "rgb(255, 59, 241)";
265
266 enum_map[color::red] = "rgb(255, 0, 0)";
267 enum_map[color::green] = "rgb(0, 255, 0)";
268 enum_map[color::blue] = "rgb(0, 0, 255)";
269
270 enum_map[color::asamablue] = "rgb(1, 137, 255)";
271 enum_map[color::asamaorange] = "rgb(236, 75, 37)";
272 enum_map[color::asamapink] = "rgb(200, 56, 81)";
273
274 // Yellows
275 enum_map[color::kanzoiro] = "rgb(255, 137, 54)";
276 enum_map[color::kohakuiro] = "rgb(202, 105, 36)";
277 enum_map[color::kinsusutake] = "rgb(125, 78, 45)";
278 enum_map[color::daylily] = "rgb(255, 137, 54)";
279 enum_map[color::goldenyellow] = "rgb(255, 164, 0)";
280 enum_map[color::hellayellow] = "rgb(255, 255, 0)";
281 enum_map[color::antiquewhite] = "rgb(250, 235, 215)";
282 enum_map[color::lemonchiffon] = "rgb(255, 250, 205)";
283 enum_map[color::goldenrod] = "rgb(250, 250, 210)";
284 enum_map[color::navajowhite] = "rgb(255, 222, 173)";
285
286 enum_map[color::ivory] = "rgb(255, 255, 240)";
287 enum_map[color::gold] = "rgb(255, 215, 0)";
288
289 enum_map[color::duboisyellow1] = "rgb(255, 255, 5)";
290 enum_map[color::duboisyellow2] = "rgb(255, 234, 18)";
291 enum_map[color::duboisyellow3] = "rgb(255, 215, 1)";
292
293 // Orange
294 enum_map[color::orange] = "rgb(255, 165, 0)";
295 enum_map[color::orangered] = "rgb(255, 69, 0)";
296 enum_map[color::redorange] = "rgb(220, 48, 35)";
297 enum_map[color::darkorange] = "rgb(255, 140, 17)";
298 enum_map[color::dutchorange] = "rgb(250, 155, 30)";
299 enum_map[color::internationalorange] = "rgb(255, 79, 0)";
300
301 // Brown
302 enum_map[color::duboisbrown1] = "rgb(128, 5, 5)";
303 enum_map[color::duboisbrown2] = "rgb(134, 90, 61)";
304 enum_map[color::duboisbrown3] = "rgb(81, 55, 42)";
305 enum_map[color::duboisbrown4] = "rgb(197, 146, 37)";
306 enum_map[color::duboisbrown5] ="rgb(255, 240, 200)";
307
308 // Reds
309 enum_map[color::foreigncrimson] = "rgb(201, 31, 55)";
310 enum_map[color::ginshu] = "rgb(188, 45, 41)";
311 enum_map[color::akabeni] = "rgb(195, 39,43)";
312 enum_map[color::akebonoiro] = "rgb(250, 123, 98)";
313
314 enum_map[color::ochre] = "rgb(255, 78, 32)";
315 enum_map[color::sohi] = "rgb(227, 92, 56)";
316 enum_map[color::benikaba] = "rgb(157, 43, 34)";
317 enum_map[color::benitobi] = "rgb(145, 50, 40)";
318 enum_map[color::ake] = "rgb(207, 58, 36)";
319
320 enum_map[color::crimson] = "rgb(220, 20, 60)";
321 enum_map[color::tomato] = "rgb(255, 99, 71)";
322 enum_map[color::coral] = "rgb(255, 127, 80)";
323 enum_map[color::salmon] = "rgb(250, 128, 114)";
324
325 enum_map[color::duboisred1] = "rgb(255, 29, 16)";
326 enum_map[color::duboisred2] = "rgb(249,110, 11)";
327 enum_map[color::duboisred3] = "rgb(215, 25, 50)";
328
329 // Greens
330 enum_map[color::byakuroku] = "rgb(165, 186, 147)";
331 enum_map[color::usumoegi] = "rgb(141, 178, 85)";
332 enum_map[color::moegi] = "rgb(91, 137, 48)";
333 enum_map[color::hiwamoegi] = "rgb(122, 148, 46)";
334 enum_map[color::midori] = "rgb(42, 96, 59)";
335 enum_map[color::rokusho] = "rgb(64, 122, 82)";
336 enum_map[color::aotakeiro] = "rgb(0, 100, 66)";
337 enum_map[color::seiheki] = "rgb(58, 105, 96)";
338 enum_map[color::seijiiro] = "rgb(129, 156, 139)";
339 enum_map[color::yanagizome] = "rgb(140, 158, 94)";
340
341 enum_map[color::chartreuse] = "rgb(127, 255, 0)";
342 enum_map[color::greenyellow] = "rgb(173, 255, 47)";
343 enum_map[color::limegreen] = "rgb(50, 205, 50)";
344 enum_map[color::springgreen] = "rgb(0, 255, 127)";
345 enum_map[color::aquamarine] = "rgb(127, 255, 212)";
346
347 enum_map[color::duboisgreen1] = "rgb(5, 255, 5)";
348 enum_map[color::duboisgreen2] = "rgb(127, 225, 15)";
349 enum_map[color::duboisgreen3] = "rgb(16, 114, 9)";
350 enum_map[color::duboisgreen4] = "rgb(0, 148, 16)";
351 enum_map[color::duboisgreen5] = "rgb(24, 57, 30)";
352
353 // Blues
354 enum_map[color::ultramarine] = "rgb(93, 140, 174)";
355 enum_map[color::shinbashiiro] = "rgb(0, 108, 127)";
356 enum_map[color::hanada] = "rgb(4, 79, 103)";
357 enum_map[color::ruriiro] = "rgb(31, 71, 136)";
358 enum_map[color::bellflower] = "rgb(25, 31, 69)";
359 enum_map[color::navy] = "rgb(0, 49, 113)";
360 enum_map[color::asagiiro] = "rgb(72, 146, 155)";
361 enum_map[color::indigo] = "rgb(38, 67, 72)";
362 enum_map[color::rurikon] = "rgb(27, 41, 75)";
363 enum_map[color::cyan] = "rgb(0, 255, 255)";
364
365 enum_map[color::lightcyan] = "rgb(224, 255, 255)";
366 enum_map[color::powderblue] = "rgb(176, 224, 230)";
367 enum_map[color::steelblue] = "rgb(70, 130, 237)";
368 enum_map[color::cornflowerblue] = "rgb(100, 149, 237)";
369 enum_map[color::deepskyblue] = "rgb(0, 191, 255)";
370 enum_map[color::dodgerblue] = "rgb(30, 144, 255)";
371 enum_map[color::lightblue] = "rgb(173, 216, 230)";
372 enum_map[color::skyblue] = "rgb(135, 206, 235)";
373 enum_map[color::lightskyblue] = "rgb(173, 206, 250)";
374 enum_map[color::midnightblue] = "rgb(25, 25, 112)";
375
376 enum_map[color::mediumblue] = "rgb(0, 0, 205)";
377 enum_map[color::royalblue] = "rgb(65, 105, 225)";
378 enum_map[color::darkslateblue] = "rgb(72, 61, 139)";
379 enum_map[color::slateblue] = "rgb(106, 90, 205)";
380 enum_map[color::azure] = "rgb(240, 255, 255)";
381 enum_map[color::crayolacerulean] = "rgb(29, 172, 214)";
382
383 enum_map[color::duboisblue1] = "rgb(37, 42, 255)";
384 enum_map[color::duboisblue2] = "rgb(100, 150, 245)";
385 enum_map[color::duboisblue3] = "rgb(74, 87, 129)";
386 enum_map[color::duboisblue4] = "rgb(49, 64, 103)";
387
388 enum_map[color::blueprintlight] = "rgb(0, 25, 166)";
389 enum_map[color::blueprint] = "rgb(0, 20, 132)";
390 enum_map[color::blueprintdark] = "rgb(0, 16, 106)";
391
392 // Purples
393 enum_map[color::wisteria] = "rgb(135, 95, 154)";
394 enum_map[color::murasaki] = "rgb(79, 40, 75)";
395 enum_map[color::ayameiro] = "rgb(118, 53, 104)";
396 enum_map[color::peony] = "rgb(164, 52, 93)";
397 enum_map[color::futaai] = "rgb(97, 78, 110)";
398 enum_map[color::benimidori] = "rgb(120, 119, 155)";
399 enum_map[color::redwisteria] = "rgb(187, 119, 150)";
400 enum_map[color::botan] = "rgb(164, 52, 93)";
401 enum_map[color::kokimurasaki] = "rgb(58, 36, 59)";
402 enum_map[color::usuiro] = "rgb(168, 124, 160)";
403
404 enum_map[color::blueviolet] = "rgb(138, 43, 226)";
405 enum_map[color::darkmagenta] = "rgb(139, 0, 139)";
406 enum_map[color::darkviolet] = "rgb(148, 0, 211)";
407 enum_map[color::thistle] = "rgb(216, 191, 216)";
408 enum_map[color::plum] = "rgb(221, 160, 221)";
409 enum_map[color::violet] = "rgb(238, 130, 238)";
410 enum_map[color::magenta] = "rgb(255, 0, 255)";
411 enum_map[color::dfuschia] = "rgb(255, 35, 255)";
412 enum_map[color::deeppink] = "rgb(255, 20, 147)";
413 enum_map[color::hotpink] = "rgb(255, 105, 180)";
414 enum_map[color::pink] = "rgb(255, 192, 203)";
415
416 enum_map[color::palevioletred] = "rgb(219, 112, 147)";
417 enum_map[color::mediumvioletred] = "rgb(199, 21, 133)";
418 enum_map[color::lavender] = "rgb(230, 230, 250)";
419 enum_map[color::orchid] = "rgb(218, 112, 214)";
420 enum_map[color::mediumorchid] = "rgb(186, 85, 211)";
421 enum_map[color::darkestmagenta] = "rgb(180, 0, 180)";
422 enum_map[color::mediumpurple] = "rgb(147, 112, 219)";
423 enum_map[color::purple] = "rgb(128, 0, 128)";
424 enum_map[color::dustyrose] = "rgb(191, 136, 187)";
425 enum_map[color::atmosphericp] = "rgb(228, 210, 231)";
426
427 enum_map[color::none] = "rgb(1, 0, 0)";
428 enum_map[color::last] = "rgb(0, 0, 1)";
429
430 // Error check to make sure all the colors have names/values.
431 if (enum_map.size() != color_max_size + 1)
432 {
433 string m("to_string(color)::color map size fail ");
434 m += k::newline;
435 m += std::to_string(enum_map.size());
436 m += " not equal to named colors of size ";
437 m += k::newline;
438 m += std::to_string(color_max_size);
439 throw std::runtime_error(m);
440 }
441 }
442 return enum_map[e];
443}
444
445
446/// Color quantified as integral RGB components in the range [0,255].
447/// aka like Scalar in OpenCV.
448struct color_qi
449{
450 using itype = unsigned short;
451
452 itype r;
453 itype g;
454 itype b;
455
456 // Return "rgb(64, 64, 64)";
457
458 static string
459 to_string(color_qi s)
460 {
461 std::ostringstream oss;
462 oss << "rgb(" << s.r << ',' << s.g << ',' << s.b << ")";
463 return oss.str();
464 }
465
466 // From "rgb(64, 64, 64)";
467 static color_qi
468 from_string(string s)
469 {
470 // Kill rgb() enclosing, if be.
471 if (s.empty() || s.size() < 5 || s[0] != 'r')
472 {
473 string m("color_qi::from_string input is not in rbg form: ");
474 m += s;
475 m += k::newline;
476 throw std::runtime_error(m);
477 }
478 else
479 {
480 s.pop_back();
481 s = s.substr(4);
482 }
483
484 // String stream which eats whitespace and knows number separation.
485 std::istringstream iss(s);
486 iss >> std::skipws;
487
488 char c(0);
489
490 ushort rs(0);
491 iss >> rs;
492 itype r = static_cast<itype>(rs);
493 iss >> c;
494
495 ushort gs(0);
496 iss >> gs;
497 itype g = static_cast<itype>(gs);
498 iss >> c;
499
500 ushort bs(0);
501 iss >> bs;
502 itype b = static_cast<itype>(bs);
503
504 return color_qi(r, g, b);
505 }
506
507 color_qi() = default;
508 color_qi(const color_qi&) = default;
509 color_qi& operator=(const color_qi&) = default;
510
511 // auto operator<=>(const color_qi&) const = default;
512
513 color_qi(itype ra, itype ga, itype ba) : r(ra), g(ga), b(ba) { }
514
515 color_qi(const color e)
516 {
517 color_qi klr = from_string(svg::to_string(e));
518 r = klr.r;
519 b = klr.b;
520 g = klr.g;
521 }
522};
523
524inline bool
525operator==(const color_qi& c1, const color_qi& c2)
526{
527 const bool t1 = c1.r == c2.r;
528 const bool t2 = c1.g == c2.g;
529 const bool t3 = c1.b == c2.b;
530 return t1 && t2 && t3;
531}
532
533
534/// Convert color_qi to string.
535const std::string
536to_string(const color_qi klr)
537{ return color_qi::to_string(klr); }
538
539
540/**
541 Color quantified as floating point HSV components in the range [0,1].
542
543 https://web.archive.org/web/20150303174723/
544 http://en.literateprograms.org/RGB_to_HSV_color_space_conversion_(C)
545*/
546struct color_qf
547{
548 using ftype = float;
549
550 ftype h; /// Hue degree between 0.0 and 360.0
551 ftype s; /// Saturation between 0.0 (gray) and 1.0
552 ftype v; /// Value between 0.0 (black) and 1.0
553
554 color_qf() = default;
555 color_qf(const color_qf&) = default;
556 color_qf& operator=(const color_qf&) = default;
557
558 // auto operator<=>(const color_qf&) const = default;
559
560 color_qf(ftype vh, ftype vs, ftype vv) : h(vh), s(vs), v(vv) { }
561
562 // Conversion constructor, convert from RGB to HSV.
563 color_qf(const color_qi& cqi)
564 {
565 auto hsv = rgb_to_hsv(cqi);
566 h = hsv.h;
567 s = hsv.s;
568 v = hsv.v;
569 }
570
571 color_qf(const color e)
572 {
573 color_qi klr(e);
574 *this = color_qf(klr);
575 }
576
577 static string
578 to_string(color_qf s)
579 {
580 std::ostringstream oss;
581 oss << std::fixed << std::setprecision(2);
582 oss << "hsv(" << s.h << ',' << s.s << ',' << s.v << ")";
583 return oss.str();
584 }
585
586 /// Back to RGB
587 /// https://www.rapidtables.com/convert/color/hsv-to-rgb.html
588 color_qi
589 to_color_qi() const
590 { return hsv_to_rgb({ h, s, v }); }
591
592 /// Convert RGB to HSV
593 color_qf
594 rgb_to_hsv(const color_qi& rgb) const
595 {
596 color_qf hsv;
597
598 double r = rgb.r / 255.0;
599 double g = rgb.g / 255.0;
600 double b = rgb.b / 255.0;
601
602 double max_val = std::max({r, g, b});
603 double min_val = std::min({r, g, b});
604 double delta = max_val - min_val;
605
606 // Hue calculation
607 if (delta == 0.0)
608 {
609 hsv.h = 0.0;
610 }
611 else if (max_val == r)
612 {
613 hsv.h = 60.0 * fmod(((g - b) / delta), 6.0);
614 }
615 else if (max_val == g)
616 {
617 hsv.h = 60.0 * (((b - r) / delta) + 2.0);
618 }
619 else
620 {
621 // max_val == b
622 hsv.h = 60.0 * (((r - g) / delta) + 4.0);
623 }
624
625 if (hsv.h < 0.0)
626 hsv.h += 360.0;
627
628 // Saturation calculation
629 hsv.s = (max_val == 0.0) ? 0.0 : (delta / max_val);
630
631 // Value calculation
632 hsv.v = max_val;
633
634 return hsv;
635 }
636
637
638 /// Convert HSV to RGB
639 color_qi
640 hsv_to_rgb(const color_qf& hsv) const
641 {
642 color_qi rgb;
643
644 double c = hsv.v * hsv.s;
645 double x = c * (1.0 - std::abs(fmod(hsv.h / 60.0, 2.0) - 1.0));
646 double m = hsv.v - c;
647
648 double r_prime, g_prime, b_prime;
649
650 if (hsv.h >= 0.0 && hsv.h < 60.0)
651 {
652 r_prime = c; g_prime = x; b_prime = 0.0;
653 }
654 else if (hsv.h >= 60.0 && hsv.h < 120.0)
655 {
656 r_prime = x; g_prime = c; b_prime = 0.0;
657 }
658 else if (hsv.h >= 120.0 && hsv.h < 180.0)
659 {
660 r_prime = 0.0; g_prime = c; b_prime = x;
661 }
662 else if (hsv.h >= 180.0 && hsv.h < 240.0)
663 {
664 r_prime = 0.0; g_prime = x; b_prime = c;
665 }
666 else if (hsv.h >= 240.0 && hsv.h < 300.0)
667 {
668 r_prime = x; g_prime = 0.0; b_prime = c;
669 }
670 else
671 {
672 // 300° - 360°
673 r_prime = c; g_prime = 0.0; b_prime = x;
674 }
675
676 using itype = color_qi::itype;
677 rgb.r = static_cast<itype>(std::clamp((r_prime + m) * 255.0, 0.0, 255.0));
678 rgb.g = static_cast<itype>(std::clamp((g_prime + m) * 255.0, 0.0, 255.0));
679 rgb.b = static_cast<itype>(std::clamp((b_prime + m) * 255.0, 0.0, 255.0));
680
681 return rgb;
682 }
683
684 /// Interpolated tinting algorithm from palette (ciecam16j70_palette).
685 /// @param n is the [0,10] 11-step perceptual gradation from dark to light.
686 /// Assume that color_qi has been converted to color_qf.
687 color_qi
688 tint_perceptual(const uint n)
689 {
690 // 11 steps total (0-10)
691 uint step = std::min(n, 10u);
692
693 // White is HSV(any, 0.0, 1.0)
694 // const color_qf white_hsv = { h, 0.0, 1.0};
695
696 // Use a custom interpolation curve
697 // First increase value, then decrease saturation
698 color_qf result_hsv(*this);
699 if (step <= 4)
700 {
701 // For steps 0-4, t is interpolate value: base.v → 1.0
702 double t = step / 4.0;
703 result_hsv.s = s; // Keep saturation
704 result_hsv.v = v + t * (1.0 - v);
705 }
706 else
707 {
708 // For steps 5-10, interpolate saturation: 1.0 → 0.3
709 double sat_t = (step - 4) / 6.0; // 0.0 to 1.0
710 double target_sat = 1.0 - 0.7 * sat_t; // 1.0 → 0.3
711 result_hsv.s = s * target_sat;
712 result_hsv.v = 1.0; // Max value
713 }
714
715 return hsv_to_rgb(result_hsv);
716 }
717
718 /// Procedural tinting algorithm.
719 /// @param tp tint percentage original color remaining
720 /// @param trange upper/lower bounds for percentage range (0, 100)
721 color_qi
722 tint_percentage(const double tp,
723 const double rmin = 0, const double rmax = 100)
724 {
725 double percentage = std::clamp(tp, rmin, rmax);
726
727 // Convert percentage to adjustment factor
728 // 10% tint = 10% of original saturation
729 // 90% tint = 90% of original saturation
730 double saturationf = percentage / 100.0;
731
732 // Alternative: Mix with white by reducing saturation and increasing value
733 color_qf result_hsv(*this);
734
735 // Reduce saturation based on tint percentage
736 result_hsv.s *= saturationf;
737
738 // Slightly increase value/brightness for tint effect
739 // White has maximum brightness, so tinting moves toward value = 1.0
740 result_hsv.v = v + (1.0 - v) * (1.0 - saturationf) * 0.5;
741
742 return hsv_to_rgb(result_hsv);
743 }
744};
745
746
747/// Convert color_qf to string.
748const std::string
749to_string(const color_qf klr)
750{ return color_qf::to_string(klr); }
751
752
753/// Less than compare for color_qf
754bool
755color_qf_lt_hue_v1(const color_qf& k1, const color_qf& k2)
756{
757 const bool eqh = k1.h == k2.h;
758 const bool lth = k1.h < k2.h;
759 const bool lts = k1.v < k2.v;
760
761 if (eqh)
762 return lts;
763 else
764 return lth;
765};
766
767bool
768color_qf_lt_hue_v2(const color_qf& k1, const color_qf& k2)
769{
770 const bool eqh = k1.h == k2.h;
771 const bool lth = k1.h < k2.h;
772
773 if (eqh)
774 {
775 const color_qf::ftype k1hyp = std::sqrt((k1.s * k1.s) + (k1.v * k1.v));
776 const color_qf::ftype k2hyp = std::sqrt((k2.s * k2.s) + (k2.v * k2.v));
777 const bool ltothers = k1hyp < k2hyp;
778 return ltothers;
779 }
780 else
781 return lth;
782};
783
784color_qf::ftype
785color_qf_distance(const color_qf& k1, const color_qf& k2)
786{
787 using ftype = color_qf::ftype;
788 const ftype sdist = std::abs(k1.s - k2.s);
789 const ftype vdist = std::abs(k1.v - k2.v);
790
791 const ftype habs = std::abs(k1.h - k2.h);
792 const ftype hdist = habs > 180 ? 360 - habs : habs;
793
794 // Euclidean distance.
795 //return std::sqrt(hdist*hdist + sdist*sdist + vdist*vdist);
796
797 // Weighted.
798 //return hdist*hweight + sdist*sweight + vdist*vweight;
799 return hdist*1.2 + sdist*2 + vdist*3;
800}
801
802
803/// Default compare distances from k1,k2 to black
804bool
805color_qf_lt_v(const color_qf& k1, const color_qf& k2)
806{
807 using ftype = color_qf::ftype;
808
809 const color_qf originklr = color::black;
810
811 // Compute distance from both arguments to compare color.
812 ftype d1 = color_qf_distance(k1, originklr);
813 ftype d2 = color_qf_distance(k2, originklr);
814 const bool ret = d1 < d2;
815 return ret;
816};
817
818
819/// Forwarding function.
820inline bool
821color_qf_lt(const color_qf& k1, const color_qf& k2)
822{ return color_qf_lt_v(k1, k2); };
823
824
825inline bool
826operator==(const color_qf& c1, const color_qf& c2)
827{
828 const bool t1 = c1.h == c2.h;
829 const bool t2 = c1.s == c2.s;
830 const bool t3 = c1.v == c2.v;
831 return t1 && t2 && t3;
832}
833
834inline bool
835operator<(const color_qf& c1, const color_qf& c2)
836{ return color_qf_lt(c1, c2); }
837
838
839/// Return a variant on saturation/value only.
840color_qf
841mutate_color_qf(const color_qf& k)
842{
843 color_qf ret(k);
844 static std::mt19937_64 rg(std::random_device{}());
845 auto distr = std::uniform_real_distribution<>(0.5, 1);
846
847 // saturation 0.5 to 1, aka more saturated.
848 double stry = distr(rg);
849 if (ret.s < stry)
850 ret.s = stry;
851
852 // value 0.5 to 1, aka less dark
853 double vtry = distr(rg);
854 if (ret.v < vtry)
855 ret.v = vtry;
856
857 return ret;
858}
859
860
861/**
862 Combine color a with color b in percentages ad and ab, respectively.
863
864 To average, constrain paramters ad and ab such that: ad + ab == 2.
865
866 Like so:
867 ushort ur = (a.r + b.r) / 2;
868 ushort ug = (a.g + b.g) / 2;
869 ushort ub = (a.b + b.b) / 2;
870*/
871color_qi
872combine_color_qi(const color_qi& a, const double ad,
873 const color_qi& b, const double bd)
874{
875 double denom = ad + bd;
876 double ur = ((a.r * ad) + (b.r * bd)) / denom;
877 double ug = ((a.g * ad) + (b.g * bd)) / denom;
878 double ub = ((a.b * ad) + (b.b * bd)) / denom;
879
880 using itype = color_qi::itype;
881 itype cr = static_cast<itype>(ur);
882 itype cg = static_cast<itype>(ug);
883 itype cb = static_cast<itype>(ub);
884 return color_qi { cr, cg, cb };
885}
886
887/// Average two colors, return the result.
888color_qi
889average_color_qi(const color_qi& a, const color_qi& b)
890{ return combine_color_qi(a, 1.0, b, 1.0); }
891
892
893/// Types for Color iteration and combinatorics.
894using color_qis = std::vector<color_qi>;
895using color_qfs = std::vector<color_qf>;
896
897} // namespace svg
898
899#endif
svg::color_max_size
constexpr uint color_max_size
Total number of enumerated colors.
Definition a60-svg-color.h:226
svg::color
color
Color enumerated as types.
Definition a60-svg-color.h:42
svg::ushort
unsigned short ushort
Base integer type: positive and negative, signed integral value.
Definition a60-svg.h:57
svg::color_qfs
std::vector< color_qf > color_qfs
Definition a60-svg-color.h:895
svg::to_string
const string to_string(const unit e)
Definition a60-svg-base-types.h:41
svg::color_qis
std::vector< color_qi > color_qis
Types for Color iteration and combinatorics.
Definition a60-svg-color.h:894
svg::operator<
bool operator<(const color_qf &c1, const color_qf &c2)
Definition a60-svg-color.h:835
svg::average_color_qi
color_qi average_color_qi(const color_qi &a, const color_qi &b)
Average two colors, return the result.
Definition a60-svg-color.h:889
svg::mutate_color_qf
color_qf mutate_color_qf(const color_qf &k)
Return a variant on saturation/value only.
Definition a60-svg-color.h:841
svg::color_qf_lt_hue_v2
bool color_qf_lt_hue_v2(const color_qf &k1, const color_qf &k2)
Definition a60-svg-color.h:768
svg::operator==
bool operator==(const color_qi &c1, const color_qi &c2)
Definition a60-svg-color.h:525
svg::combine_color_qi
color_qi combine_color_qi(const color_qi &a, const double ad, const color_qi &b, const double bd)
Definition a60-svg-color.h:872
svg::color_qf_distance
color_qf::ftype color_qf_distance(const color_qf &k1, const color_qf &k2)
Definition a60-svg-color.h:785
svg::color_qf_lt_v
bool color_qf_lt_v(const color_qf &k1, const color_qf &k2)
Default compare distances from k1,k2 to black.
Definition a60-svg-color.h:805
svg::color_qf_lt
bool color_qf_lt(const color_qf &k1, const color_qf &k2)
Forwarding function.
Definition a60-svg-color.h:821
svg::uint
unsigned int uint
Definition a60-svg.h:58
svg::color_qf_lt_hue_v1
bool color_qf_lt_hue_v1(const color_qf &k1, const color_qf &k2)
Less than compare for color_qf.
Definition a60-svg-color.h:755
svg::color_qf
Definition a60-svg-color.h:547
svg::color_qf::v
ftype v
Saturation between 0.0 (gray) and 1.0.
Definition a60-svg-color.h:552
svg::color_qf::h
ftype h
Definition a60-svg-color.h:550
svg::color_qf::rgb_to_hsv
color_qf rgb_to_hsv(const color_qi &rgb) const
Convert RGB to HSV.
Definition a60-svg-color.h:594
svg::color_qf::color_qf
color_qf(const color e)
Definition a60-svg-color.h:571
svg::color_qf::color_qf
color_qf(ftype vh, ftype vs, ftype vv)
Definition a60-svg-color.h:560
svg::color_qf::color_qf
color_qf()=default
Value between 0.0 (black) and 1.0.
svg::color_qf::ftype
float ftype
Definition a60-svg-color.h:548
svg::color_qf::tint_percentage
color_qi tint_percentage(const double tp, const double rmin=0, const double rmax=100)
Procedural tinting algorithm.
Definition a60-svg-color.h:722
svg::color_qf::s
ftype s
Hue degree between 0.0 and 360.0.
Definition a60-svg-color.h:551
svg::color_qf::operator=
color_qf & operator=(const color_qf &)=default
svg::color_qf::color_qf
color_qf(const color_qf &)=default
svg::color_qf::to_string
static string to_string(color_qf s)
Definition a60-svg-color.h:578
svg::color_qf::tint_perceptual
color_qi tint_perceptual(const uint n)
Interpolated tinting algorithm from palette (ciecam16j70_palette).
Definition a60-svg-color.h:688
svg::color_qf::color_qf
color_qf(const color_qi &cqi)
Definition a60-svg-color.h:563
svg::color_qf::to_color_qi
color_qi to_color_qi() const
Back to RGB https://www.rapidtables.com/convert/color/hsv-to-rgb.html.
Definition a60-svg-color.h:589
svg::color_qf::hsv_to_rgb
color_qi hsv_to_rgb(const color_qf &hsv) const
Convert HSV to RGB.
Definition a60-svg-color.h:640
svg::color_qi
Color quantified as integral RGB components in the range [0,255]. aka like Scalar in OpenCV.
Definition a60-svg-color.h:449
svg::color_qi::color_qi
color_qi(const color_qi &)=default
svg::color_qi::operator=
color_qi & operator=(const color_qi &)=default
svg::color_qi::color_qi
color_qi()=default
svg::color_qi::to_string
static string to_string(color_qi s)
Definition a60-svg-color.h:459
svg::color_qi::b
itype b
Definition a60-svg-color.h:454
svg::color_qi::g
itype g
Definition a60-svg-color.h:453
svg::color_qi::color_qi
color_qi(itype ra, itype ga, itype ba)
Definition a60-svg-color.h:513
svg::color_qi::itype
unsigned short itype
Definition a60-svg-color.h:450
svg::color_qi::from_string
static color_qi from_string(string s)
Definition a60-svg-color.h:468
svg::color_qi::r
itype r
Definition a60-svg-color.h:452
svg::color_qi::color_qi
color_qi(const color e)
Definition a60-svg-color.h:515
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