Convert HEX to closest X11 Color Number
I\'m looking for a Algorithm/Way to convert given HEX (e.g. #111111 R:0x11, G:0x11, B:0x11) to the closest X11 color number (Terminal is either 88 or 256 colors) using either Py
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I had the same issue (taking an existing vim colorscheme with gvim hex colors and filling in the terminal color values). Here's the script I used (although the ColorDist function would probably benefit from a better color distance metric like some of the other posters are suggesting)
import re import math colors = { '000000': '16', '00005f': '17', '000087': '18', '0000af': '19', '0000d7': '20', '0000ff': '21', '005f00': '22', '005f5f': '23', '005f87': '24', '005faf': '25', '005fd7': '26', '005fff': '27', '008700': '28', '00875f': '29', '008787': '30', '0087af': '31', '0087d7': '32', '0087ff': '33', '00af00': '34', '00af5f': '35', '00af87': '36', '00afaf': '37', '00afd7': '38', '00afff': '39', '00d700': '40', '00d75f': '41', '00d787': '42', '00d7af': '43', '00d7d7': '44', '00d7ff': '45', '00ff00': '46', '00ff5f': '47', '00ff87': '48', '00ffaf': '49', '00ffd7': '50', '00ffff': '51', '5f0000': '52', '5f005f': '53', '5f0087': '54', '5f00af': '55', '5f00d7': '56', '5f00ff': '57', '5f5f00': '58', '5f5f5f': '59', '5f5f87': '60', '5f5faf': '61', '5f5fd7': '62', '5f5fff': '63', '5f8700': '64', '5f875f': '65', '5f8787': '66', '5f87af': '67', '5f87d7': '68', '5f87ff': '69', '5faf00': '70', '5faf5f': '71', '5faf87': '72', '5fafaf': '73', '5fafd7': '74', '5fafff': '75', '5fd700': '76', '5fd75f': '77', '5fd787': '78', '5fd7af': '79', '5fd7d7': '80', '5fd7ff': '81', '5fff00': '82', '5fff5f': '83', '5fff87': '84', '5fffaf': '85', '5fffd7': '86', '5fffff': '87', '870000': '88', '87005f': '89', '870087': '90', '8700af': '91', '8700d7': '92', '8700ff': '93', '875f00': '94', '875f5f': '95', '875f87': '96', '875faf': '97', '875fd7': '98', '875fff': '99', '878700': '100', '87875f': '101', '878787': '102', '8787af': '103', '8787d7': '104', '8787ff': '105', '87af00': '106', '87af5f': '107', '87af87': '108', '87afaf': '109', '87afd7': '110', '87afff': '111', '87d700': '112', '87d75f': '113', '87d787': '114', '87d7af': '115', '87d7d7': '116', '87d7ff': '117', '87ff00': '118', '87ff5f': '119', '87ff87': '120', '87ffaf': '121', '87ffd7': '122', '87ffff': '123', 'af0000': '124', 'af005f': '125', 'af0087': '126', 'af00af': '127', 'af00d7': '128', 'af00ff': '129', 'af5f00': '130', 'af5f5f': '131', 'af5f87': '132', 'af5faf': '133', 'af5fd7': '134', 'af5fff': '135', 'af8700': '136', 'af875f': '137', 'af8787': '138', 'af87af': '139', 'af87d7': '140', 'af87ff': '141', 'afaf00': '142', 'afaf5f': '143', 'afaf87': '144', 'afafaf': '145', 'afafd7': '146', 'afafff': '147', 'afd700': '148', 'afd75f': '149', 'afd787': '150', 'afd7af': '151', 'afd7d7': '152', 'afd7ff': '153', 'afff00': '154', 'afff5f': '155', 'afff87': '156', 'afffaf': '157', 'afffd7': '158', 'afffff': '159', 'd70000': '160', 'd7005f': '161', 'd70087': '162', 'd700af': '163', 'd700d7': '164', 'd700ff': '165', 'd75f00': '166', 'd75f5f': '167', 'd75f87': '168', 'd75faf': '169', 'd75fd7': '170', 'd75fff': '171', 'd78700': '172', 'd7875f': '173', 'd78787': '174', 'd787af': '175', 'd787d7': '176', 'd787ff': '177', 'd7af00': '178', 'd7af5f': '179', 'd7af87': '180', 'd7afaf': '181', 'd7afd7': '182', 'd7afff': '183', 'd7d700': '184', 'd7d75f': '185', 'd7d787': '186', 'd7d7af': '187', 'd7d7d7': '188', 'd7d7ff': '189', 'd7ff00': '190', 'd7ff5f': '191', 'd7ff87': '192', 'd7ffaf': '193', 'd7ffd7': '194', 'd7ffff': '195', 'ff0000': '196', 'ff005f': '197', 'ff0087': '198', 'ff00af': '199', 'ff00d7': '200', 'ff00ff': '201', 'ff5f00': '202', 'ff5f5f': '203', 'ff5f87': '204', 'ff5faf': '205', 'ff5fd7': '206', 'ff5fff': '207', 'ff8700': '208', 'ff875f': '209', 'ff8787': '210', 'ff87af': '211', 'ff87d7': '212', 'ff87ff': '213', 'ffaf00': '214', 'ffaf5f': '215', 'ffaf87': '216', 'ffafaf': '217', 'ffafd7': '218', 'ffafff': '219', 'ffd700': '220', 'ffd75f': '221', 'ffd787': '222', 'ffd7af': '223', 'ffd7d7': '224', 'ffd7ff': '225', 'ffff00': '226', 'ffff5f': '227', 'ffff87': '228', 'ffffaf': '229', 'ffffd7': '230', 'ffffff': '231', '080808': '232', '121212': '233', '1c1c1c': '234', '262626': '235', '303030': '236', '3a3a3a': '237', '444444': '238', '4e4e4e': '239', '585858': '240', '626262': '241', '6c6c6c': '242', '767676': '243', '808080': '244', '8a8a8a': '245', '949494': '246', '9e9e9e': '247', 'a8a8a8': '248', 'b2b2b2': '249', 'bcbcbc': '250', 'c6c6c6': '251', 'd0d0d0': '252', 'dadada': '253', 'e4e4e4': '254', 'eeeeee': '255', } ## Example line from a vim colorscheme file ##hi Normal ctermfg=NONE ctermbg=NONE gui=NONE guifg=#b7af9f guibg=#202020 def Decompose(hexval): return float(int(hexval[0:2], 16)), float(int(hexval[2:4], 16)), float(int(hexval[4:6], 16)) def Normalize(r, g, b): magsqr = r*r + g*g + b*b if magsqr < 0.0001: return 0.0, 0.0, 0.0 n = 1.0 / math.sqrt(magsqr) return r*n, g*n, b*n def ColorDist(c1, c2): c1r, c1g, c1b = Decompose(c1) c2r, c2g, c2b = Decompose(c2) dr = c1r - c2r dg = c1g - c2g db = c1b - c2b return dr*dr + dg*dg + db*db def BestMatch(hexval): best = None bestdist = 0.0 for key in colors.keys(): dist = ColorDist(hexval, key) if best is None or dist < bestdist: best = colors[key] bestdist = dist return best ## 1 2 3 4 5 6 fg = re.compile(r'^(.*)(ctermfg=)NONE(.*)(guifg=#)([^ ]*)(.*)\n$') bg = re.compile(r'^(.*)(ctermbg=)NONE(.*)(guibg=#)([^ ]*)(.*)\n$') with open(r'input_color_scheme.vim', 'r') as f: with open(r'output_color_scheme.vim', 'w') as fout: for line in f.readlines(): fgmatch = fg.match(line) if fgmatch is not None: line = (fgmatch.group(1) + fgmatch.group(2) + BestMatch(fgmatch.group(5)) + fgmatch.group(3) + fgmatch.group(4) + fgmatch.group(5) + fgmatch.group(6)) + '\n' bgmatch = bg.match(line) if bgmatch is not None: line = (bgmatch.group(1) + bgmatch.group(2) + BestMatch(bgmatch.group(5)) + bgmatch.group(3) + bgmatch.group(4) + bgmatch.group(5) + bgmatch.group(6) + '\n') ## -- print the line fout.write(line)讨论(0) -
This is a C implementation, though it should be easy to convert it to other languages. There is a JavaScript implementation at the end of this post. Do note that the C implementation uses integer arithmetic:
// Convert RGB24 to xterm-256 8-bit value // For simplicity, assume RGB space is perceptually uniform. // There are 5 places where one of two outputs needs to be chosen when the // input is the exact middle: // - The r/g/b channels and the gray value: the higher value output is chosen. // - If the gray and color have same distance from the input - color is chosen. static int rgb_to_x256(uint8_t r, uint8_t g, uint8_t b) { // Calculate the nearest 0-based color index at 16 .. 231 # define v2ci(v) (v < 48 ? 0 : v < 115 ? 1 : (v - 35) / 40) int ir = v2ci(r), ig = v2ci(g), ib = v2ci(b); // 0..5 each # define color_index() (36 * ir + 6 * ig + ib) /* 0..215, lazy evaluation */ // Calculate the nearest 0-based gray index at 232 .. 255 int average = (r + g + b) / 3; int gray_index = average > 238 ? 23 : (average - 3) / 10; // 0..23 // Calculate the represented colors back from the index static const int i2cv[6] = {0, 0x5f, 0x87, 0xaf, 0xd7, 0xff}; int cr = i2cv[ir], cg = i2cv[ig], cb = i2cv[ib]; // r/g/b, 0..255 each int gv = 8 + 10 * gray_index; // same value for r/g/b, 0..255 // Return the one which is nearer to the original input rgb value # define dist_square(A,B,C, a,b,c) ((A-a)*(A-a) + (B-b)*(B-b) + (C-c)*(C-c)) int color_err = dist_square(cr, cg, cb, r, g, b); int gray_err = dist_square(gv, gv, gv, r, g, b); return color_err <= gray_err ? 16 + color_index() : 232 + gray_index; }This is the same implementation which is currently used by
tmuxandmpv. You can find some explanation of the algorithm at the tmux pull request on github.JavaScript implementation
// Convert RGB24 to xterm-256 8-bit value // For simplicity, assume RGB space is perceptually uniform. // There are 5 places where one of two outputs needs to be chosen when the // input is the exact middle: // - The r/g/b channels and the gray value: the higher value output is chosen. // - If the gray and color have same distance from the input - color is chosen. function RgbToX256(r, g, b) { // Calculate the nearest 0-based color index at 16 .. 231 const v2ci = (v) => { if (v < 48) { return 0; } else if (v < 115) { return 1; } else { return Math.trunc((v - 35) / 40); } }; const ir = v2ci(r); const ig = v2ci(g); const ib = v2ci(b); const colorIndex = (36 * ir + 6 * ig + ib); // Calculate the nearest 0-based gray index at 232 .. 255 const average = Math.trunc((r + g + b) / 3); const grayIndex = average > 238 ? 23 : Math.trunc((average - 3) / 10); // Calculate the represented colors back from the index const i2cv = [0, 0x5F, 0x87, 0xAF, 0xD7, 0xFF]; const cr = i2cv[ir]; const cg = i2cv[ig]; const cb = i2cv[ib]; const gv = 8 + 10 * grayIndex; // Return the one which is nearer to the original input rgb value const distSquare = (A, B, C, a, b, c) => { return ((A - a) * (A - a) + (B - b) * (B - b) + (C - c) * (C - c)); } const colorErr = distSquare(cr, cg, cb, r, g, b); const grayErr = distSquare(gv, gv, gv, r, g, b); return colorErr <= grayErr ? 16 + colorIndex : 232 + grayIndex; } const assertEq = (result, expect) => { if (result !== expect) { return console.log("[FAIL]", `expected: ${expect}, got ${result}`); } return console.log("[PASS]", `expected: ${expect}, got ${result}`); } const tests = [{ expect: 16, rgb: [0, 0, 0] }, { expect: 17, rgb: [0, 0, 95] }, { expect: 18, rgb: [0, 0, 135] }, { expect: 19, rgb: [0, 0, 175] }, { expect: 20, rgb: [0, 0, 215] }, { expect: 21, rgb: [0, 0, 255] }, { expect: 22, rgb: [0, 95, 0] }, { expect: 23, rgb: [0, 95, 95] }, { expect: 24, rgb: [0, 95, 135] }, { expect: 25, rgb: [0, 95, 175] }, { expect: 26, rgb: [0, 95, 215] }, { expect: 27, rgb: [0, 95, 255] }, { expect: 28, rgb: [0, 135, 0] }, { expect: 29, rgb: [0, 135, 95] }, { expect: 30, rgb: [0, 135, 135] }, { expect: 31, rgb: [0, 135, 175] }, { expect: 32, rgb: [0, 135, 215] }, { expect: 33, rgb: [0, 135, 255] }, { expect: 34, rgb: [0, 175, 0] }, { expect: 35, rgb: [0, 175, 95] }, { expect: 36, rgb: [0, 175, 135] }, { expect: 37, rgb: [0, 175, 175] }, { expect: 38, rgb: [0, 175, 215] }, { expect: 39, rgb: [0, 175, 255] }, { expect: 40, rgb: [0, 215, 0] }, { expect: 41, rgb: [0, 215, 95] }, { expect: 42, rgb: [0, 215, 135] }, { expect: 43, rgb: [0, 215, 175] }, { expect: 44, rgb: [0, 215, 215] }, { expect: 45, rgb: [0, 215, 255] }, { expect: 46, rgb: [0, 255, 0] }, { expect: 47, rgb: [0, 255, 95] }, { expect: 48, rgb: [0, 255, 135] }, { expect: 49, rgb: [0, 255, 175] }, { expect: 50, rgb: [0, 255, 215] }, { expect: 51, rgb: [0, 255, 255] }, { expect: 52, rgb: [95, 0, 0] }, { expect: 53, rgb: [95, 0, 95] }, { expect: 54, rgb: [95, 0, 135] }, { expect: 55, rgb: [95, 0, 175] }, { expect: 56, rgb: [95, 0, 215] }, { expect: 57, rgb: [95, 0, 255] }, { expect: 58, rgb: [95, 95, 0] }, { expect: 59, rgb: [95, 95, 95] }, { expect: 60, rgb: [95, 95, 135] }, { expect: 61, rgb: [95, 95, 175] }, { expect: 62, rgb: [95, 95, 215] }, { expect: 63, rgb: [95, 95, 255] }, { expect: 64, rgb: [95, 135, 0] }, { expect: 65, rgb: [95, 135, 95] }, { expect: 66, rgb: [95, 135, 135] }, { expect: 67, rgb: [95, 135, 175] }, { expect: 68, rgb: [95, 135, 215] }, { expect: 69, rgb: [95, 135, 255] }, { expect: 70, rgb: [95, 175, 0] }, { expect: 71, rgb: [95, 175, 95] }, { expect: 72, rgb: [95, 175, 135] }, { expect: 73, rgb: [95, 175, 175] }, { expect: 74, rgb: [95, 175, 215] }, { expect: 75, rgb: [95, 175, 255] }, { expect: 76, rgb: [95, 215, 0] }, { expect: 77, rgb: [95, 215, 95] }, { expect: 78, rgb: [95, 215, 135] }, { expect: 79, rgb: [95, 215, 175] }, { expect: 80, rgb: [95, 215, 215] }, { expect: 81, rgb: [95, 215, 255] }, { expect: 82, rgb: [95, 255, 0] }, { expect: 83, rgb: [95, 255, 95] }, { expect: 84, rgb: [95, 255, 135] }, { expect: 85, rgb: [95, 255, 175] }, { expect: 86, rgb: [95, 255, 215] }, { expect: 87, rgb: [95, 255, 255] }, { expect: 88, rgb: [135, 0, 0] }, { expect: 89, rgb: [135, 0, 95] }, { expect: 90, rgb: [135, 0, 135] }, { expect: 91, rgb: [135, 0, 175] }, { expect: 92, rgb: [135, 0, 215] }, { expect: 93, rgb: [135, 0, 255] }, { expect: 94, rgb: [135, 95, 0] }, { expect: 95, rgb: [135, 95, 95] }, { expect: 96, rgb: [135, 95, 135] }, { expect: 97, rgb: [135, 95, 175] }, { expect: 98, rgb: [135, 95, 215] }, { expect: 99, rgb: [135, 95, 255] }, { expect: 100, rgb: [135, 135, 0] }, { expect: 101, rgb: [135, 135, 95] }, { expect: 102, rgb: [135, 135, 135] }, { expect: 103, rgb: [135, 135, 175] }, { expect: 104, rgb: [135, 135, 215] }, { expect: 105, rgb: [135, 135, 255] }, { expect: 106, rgb: [135, 175, 0] }, { expect: 107, rgb: [135, 175, 95] }, { expect: 108, rgb: [135, 175, 135] }, { expect: 109, rgb: [135, 175, 175] }, { expect: 110, rgb: [135, 175, 215] }, { expect: 111, rgb: [135, 175, 255] }, { expect: 112, rgb: [135, 215, 0] }, { expect: 113, rgb: [135, 215, 95] }, { expect: 114, rgb: [135, 215, 135] }, { expect: 115, rgb: [135, 215, 175] }, { expect: 116, rgb: [135, 215, 215] }, { expect: 117, rgb: [135, 215, 255] }, { expect: 118, rgb: [135, 255, 0] }, { expect: 119, rgb: [135, 255, 95] }, { expect: 120, rgb: [135, 255, 135] }, { expect: 121, rgb: [135, 255, 175] }, { expect: 122, rgb: [135, 255, 215] }, { expect: 123, rgb: [135, 255, 255] }, { expect: 124, rgb: [175, 0, 0] }, { expect: 125, rgb: [175, 0, 95] }, { expect: 126, rgb: [175, 0, 135] }, { expect: 127, rgb: [175, 0, 175] }, { expect: 128, rgb: [175, 0, 215] }, { expect: 129, rgb: [175, 0, 255] }, { expect: 130, rgb: [175, 95, 0] }, { expect: 131, rgb: [175, 95, 95] }, { expect: 132, rgb: [175, 95, 135] }, { expect: 133, rgb: [175, 95, 175] }, { expect: 134, rgb: [175, 95, 215] }, { expect: 135, rgb: [175, 95, 255] }, { expect: 136, rgb: [175, 135, 0] }, { expect: 137, rgb: [175, 135, 95] }, { expect: 138, rgb: [175, 135, 135] }, { expect: 139, rgb: [175, 135, 175] }, { expect: 140, rgb: [175, 135, 215] }, { expect: 141, rgb: [175, 135, 255] }, { expect: 142, rgb: [175, 175, 0] }, { expect: 143, rgb: [175, 175, 95] }, { expect: 144, rgb: [175, 175, 135] }, { expect: 145, rgb: [175, 175, 175] }, { expect: 146, rgb: [175, 175, 215] }, { expect: 147, rgb: [175, 175, 255] }, { expect: 148, rgb: [175, 215, 0] }, { expect: 149, rgb: [175, 215, 95] }, { expect: 150, rgb: [175, 215, 135] }, { expect: 151, rgb: [175, 215, 175] }, { expect: 152, rgb: [175, 215, 215] }, { expect: 153, rgb: [175, 215, 255] }, { expect: 154, rgb: [175, 255, 0] }, { expect: 155, rgb: [175, 255, 95] }, { expect: 156, rgb: [175, 255, 135] }, { expect: 157, rgb: [175, 255, 175] }, { expect: 158, rgb: [175, 255, 215] }, { expect: 159, rgb: [175, 255, 255] }, { expect: 160, rgb: [215, 0, 0] }, { expect: 161, rgb: [215, 0, 95] }, { expect: 162, rgb: [215, 0, 135] }, { expect: 163, rgb: [215, 0, 175] }, { expect: 164, rgb: [215, 0, 215] }, { expect: 165, rgb: [215, 0, 255] }, { expect: 166, rgb: [215, 95, 0] }, { expect: 167, rgb: [215, 95, 95] }, { expect: 168, rgb: [215, 95, 135] }, { expect: 169, rgb: [215, 95, 175] }, { expect: 170, rgb: [215, 95, 215] }, { expect: 171, rgb: [215, 95, 255] }, { expect: 172, rgb: [215, 135, 0] }, { expect: 173, rgb: [215, 135, 95] }, { expect: 174, rgb: [215, 135, 135] }, { expect: 175, rgb: [215, 135, 175] }, { expect: 176, rgb: [215, 135, 215] }, { expect: 177, rgb: [215, 135, 255] }, { expect: 178, rgb: [215, 175, 0] }, { expect: 179, rgb: [215, 175, 95] }, { expect: 180, rgb: [215, 175, 135] }, { expect: 181, rgb: [215, 175, 175] }, { expect: 182, rgb: [215, 175, 215] }, { expect: 183, rgb: [215, 175, 255] }, { expect: 184, rgb: [215, 215, 0] }, { expect: 185, rgb: [215, 215, 95] }, { expect: 186, rgb: [215, 215, 135] }, { expect: 187, rgb: [215, 215, 175] }, { expect: 188, rgb: [215, 215, 215] }, { expect: 189, rgb: [215, 215, 255] }, { expect: 190, rgb: [215, 255, 0] }, { expect: 191, rgb: [215, 255, 95] }, { expect: 192, rgb: [215, 255, 135] }, { expect: 193, rgb: [215, 255, 175] }, { expect: 194, rgb: [215, 255, 215] }, { expect: 195, rgb: [215, 255, 255] }, { expect: 196, rgb: [255, 0, 0] }, { expect: 197, rgb: [255, 0, 95] }, { expect: 198, rgb: [255, 0, 135] }, { expect: 199, rgb: [255, 0, 175] }, { expect: 200, rgb: [255, 0, 215] }, { expect: 201, rgb: [255, 0, 255] }, { expect: 202, rgb: [255, 95, 0] }, { expect: 203, rgb: [255, 95, 95] }, { expect: 204, rgb: [255, 95, 135] }, { expect: 205, rgb: [255, 95, 175] }, { expect: 206, rgb: [255, 95, 215] }, { expect: 207, rgb: [255, 95, 255] }, { expect: 208, rgb: [255, 135, 0] }, { expect: 209, rgb: [255, 135, 95] }, { expect: 210, rgb: [255, 135, 135] }, { expect: 211, rgb: [255, 135, 175] }, { expect: 212, rgb: [255, 135, 215] }, { expect: 213, rgb: [255, 135, 255] }, { expect: 214, rgb: [255, 175, 0] }, { expect: 215, rgb: [255, 175, 95] }, { expect: 216, rgb: [255, 175, 135] }, { expect: 217, rgb: [255, 175, 175] }, { expect: 218, rgb: [255, 175, 215] }, { expect: 219, rgb: [255, 175, 255] }, { expect: 220, rgb: [255, 215, 0] }, { expect: 221, rgb: [255, 215, 95] }, { expect: 222, rgb: [255, 215, 135] }, { expect: 223, rgb: [255, 215, 175] }, { expect: 224, rgb: [255, 215, 215] }, { expect: 225, rgb: [255, 215, 255] }, { expect: 226, rgb: [255, 255, 0] }, { expect: 227, rgb: [255, 255, 95] }, { expect: 228, rgb: [255, 255, 135] }, { expect: 229, rgb: [255, 255, 175] }, { expect: 230, rgb: [255, 255, 215] }, { expect: 231, rgb: [255, 255, 255] }, { expect: 232, rgb: [8, 8, 8] }, { expect: 233, rgb: [18, 18, 18] }, { expect: 234, rgb: [28, 28, 28] }, { expect: 235, rgb: [38, 38, 38] }, { expect: 236, rgb: [48, 48, 48] }, { expect: 237, rgb: [58, 58, 58] }, { expect: 238, rgb: [68, 68, 68] }, { expect: 239, rgb: [78, 78, 78] }, { expect: 240, rgb: [88, 88, 88] }, { expect: 241, rgb: [98, 98, 98] }, { expect: 242, rgb: [108, 108, 108] }, { expect: 243, rgb: [118, 118, 118] }, { expect: 244, rgb: [128, 128, 128] }, { expect: 245, rgb: [138, 138, 138] }, { expect: 246, rgb: [148, 148, 148] }, { expect: 247, rgb: [158, 158, 158] }, { expect: 248, rgb: [168, 168, 168] }, { expect: 249, rgb: [178, 178, 178] }, { expect: 250, rgb: [188, 188, 188] }, { expect: 251, rgb: [198, 198, 198] }, { expect: 252, rgb: [208, 208, 208] }, { expect: 253, rgb: [218, 218, 218] }, { expect: 254, rgb: [228, 228, 228] }, { expect: 255, rgb: [238, 238, 238] } ]; for (const { expect, rgb: [r, g, b] } of tests) { assertEq(expect, RgbToX256(r, g, b)); }讨论(0) -
Here is python implementation that is constant time:
N = [] for i, n in enumerate([47, 68, 40, 40, 40, 21]): N.extend([i]*n) def rgb_to_xterm(r, g, b): mx = max(r, g, b) mn = min(r, g, b) if (mx-mn)*(mx+mn) <= 6250: c = 24 - (252 - ((r+g+b) // 3)) // 10 if 0 <= c <= 23: return 232 + c return 16 + 36*N[r] + 6*N[g] + N[b]讨论(0) -
Go to Wolfram Alpha, type in your hex value i.e. "#acdffa". Go to the section called "Nearest named HTML colors"
I know this isn't code but you did say "algorithm/way".
Cheers
讨论(0) -
Once you know the RGB values of the X11 colors, you can determine to which of those colors a given input color is "nearest".
There is a good, quick measure of color distance here
https://stackoverflow.com/a/74033/141172
讨论(0)
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