1 |
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2 | function isIgnoredColor(arr, num, ignoredColor) {
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3 | return arr[num] === ignoredColor[0] &&
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4 | arr[num + 1] === ignoredColor[1] &&
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5 | arr[num + 2] === ignoredColor[2] &&
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6 | arr[num + 3] === ignoredColor[3];
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7 | }
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8 |
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9 | function dominantAlgorithm(arr, len, options) {
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10 | const
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11 | colorHash = {},
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12 | divider = 24,
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13 | ignoredColor = options.ignoredColor;
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14 |
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15 | for (let i = 0; i < len; i += options.step) {
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16 | let
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17 | red = arr[i],
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18 | green = arr[i + 1],
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19 | blue = arr[i + 2],
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20 | alpha = arr[i + 3];
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21 |
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22 | if (ignoredColor && isIgnoredColor(arr, i, ignoredColor)) {
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23 | continue;
|
24 | }
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25 |
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26 | const key = Math.round(red / divider) + ',' +
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27 | Math.round(green / divider) + ',' +
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28 | Math.round(blue / divider);
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29 |
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30 | if (colorHash[key]) {
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31 | colorHash[key] = [
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32 | colorHash[key][0] + red * alpha,
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33 | colorHash[key][1] + green * alpha,
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34 | colorHash[key][2] + blue * alpha,
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35 | colorHash[key][3] + alpha,
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36 | colorHash[key][4] + 1
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37 | ];
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38 | } else {
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39 | colorHash[key] = [red * alpha, green * alpha, blue * alpha, alpha, 1];
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40 | }
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41 | }
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42 |
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43 | const buffer = Object.keys(colorHash).map(key => {
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44 | return colorHash[key];
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45 | }).sort((a, b) => {
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46 | const
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47 | countA = a[4],
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48 | countB = b[4];
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49 |
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50 | return countA > countB ? -1 : countA === countB ? 0 : 1;
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51 | });
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52 |
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53 | const max = buffer[0];
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54 |
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55 | const redTotal = max[0];
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56 | const greenTotal = max[1];
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57 | const blueTotal = max[2];
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58 |
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59 | const alphaTotal = max[3];
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60 | const count = max[4];
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61 |
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62 | return alphaTotal ? [
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63 | Math.round(redTotal / alphaTotal),
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64 | Math.round(greenTotal / alphaTotal),
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65 | Math.round(blueTotal / alphaTotal),
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66 | Math.round(alphaTotal / count)
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67 | ] : options.defaultColor;
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68 | }
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69 |
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70 | function simpleAlgorithm(arr, len, options) {
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71 | let
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72 | redTotal = 0,
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73 | greenTotal = 0,
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74 | blueTotal = 0,
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75 | alphaTotal = 0,
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76 | count = 0;
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77 |
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78 | const ignoredColor = options.ignoredColor;
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79 |
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80 | for (let i = 0; i < len; i += options.step) {
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81 | const
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82 | alpha = arr[i + 3],
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83 | red = arr[i] * alpha,
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84 | green = arr[i + 1] * alpha,
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85 | blue = arr[i + 2] * alpha;
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86 |
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87 | if (ignoredColor && isIgnoredColor(arr, i, ignoredColor)) {
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88 | continue;
|
89 | }
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90 |
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91 | redTotal += red;
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92 | greenTotal += green;
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93 | blueTotal += blue;
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94 | alphaTotal += alpha;
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95 | count++;
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96 | }
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97 |
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98 | return alphaTotal ? [
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99 | Math.round(redTotal / alphaTotal),
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100 | Math.round(greenTotal / alphaTotal),
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101 | Math.round(blueTotal / alphaTotal),
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102 | Math.round(alphaTotal / count)
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103 | ] : options.defaultColor;
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104 | }
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105 |
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106 | function sqrtAlgorithm(arr, len, options) {
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107 | let
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108 | redTotal = 0,
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109 | greenTotal = 0,
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110 | blueTotal = 0,
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111 | alphaTotal = 0,
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112 | count = 0;
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113 |
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114 | const ignoredColor = options.ignoredColor;
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115 |
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116 | for (let i = 0; i < len; i += options.step) {
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117 | const
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118 | red = arr[i],
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119 | green = arr[i + 1],
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120 | blue = arr[i + 2],
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121 | alpha = arr[i + 3];
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122 |
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123 | if (ignoredColor && isIgnoredColor(arr, i, options)) {
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124 | continue;
|
125 | }
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126 |
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127 | redTotal += red * red * alpha;
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128 | greenTotal += green * green * alpha;
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129 | blueTotal += blue * blue * alpha;
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130 | alphaTotal += alpha;
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131 | count++;
|
132 | }
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133 |
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134 | return alphaTotal ? [
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135 | Math.round(Math.sqrt(redTotal / alphaTotal)),
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136 | Math.round(Math.sqrt(greenTotal / alphaTotal)),
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137 | Math.round(Math.sqrt(blueTotal / alphaTotal)),
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138 | Math.round(alphaTotal / count)
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139 | ] : options.defaultColor;
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140 | }
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141 |
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142 | const ERROR_PREFIX = 'FastAverageColor: ';
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143 |
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144 | class FastAverageColor {
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145 | |
146 |
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147 |
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148 |
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149 |
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150 |
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151 |
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152 |
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153 |
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154 |
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155 |
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156 |
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157 |
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158 |
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159 |
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160 |
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161 |
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162 |
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163 | getColorAsync(resource, options) {
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164 | if (!resource) {
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165 | return Promise.reject(Error(`${ERROR_PREFIX}call .getColorAsync() without resource.`));
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166 | } else if (typeof resource === 'string') {
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167 | return this._bindImageEvents(new Image(resource), options);
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168 | } else if (resource.complete) {
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169 | const result = this.getColor(resource, options);
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170 | return result.error ? Promise.reject(result.error) : Promise.resolve(result);
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171 | } else {
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172 | return this._bindImageEvents(resource, options);
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173 | }
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174 | }
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175 |
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176 | |
177 |
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178 |
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179 |
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180 |
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181 |
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182 |
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183 |
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184 |
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185 |
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186 |
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187 |
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188 |
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189 |
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190 |
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191 |
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192 |
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193 |
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194 | getColor(resource, options) {
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195 | options = options || {};
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196 |
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197 | const defaultColor = this._getDefaultColor(options);
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198 |
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199 | let value = defaultColor;
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200 | if (!resource) {
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201 | this._outputError(options, 'call .getColor(null) without resource.');
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202 |
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203 | return this._prepareResult(defaultColor);
|
204 | }
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205 |
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206 | const
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207 | originalSize = this._getOriginalSize(resource),
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208 | size = this._prepareSizeAndPosition(originalSize, options);
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209 |
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210 | if (!size.srcWidth || !size.srcHeight || !size.destWidth || !size.destHeight) {
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211 | this._outputError(options, `incorrect sizes for resource "${resource.src}".`);
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212 |
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213 | return this._prepareResult(defaultColor);
|
214 | }
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215 |
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216 | if (!this._ctx) {
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217 | this._canvas = this._makeCanvas();
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218 | this._ctx = this._canvas.getContext && this._canvas.getContext('2d');
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219 |
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220 | if (!this._ctx) {
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221 | this._outputError(options, 'Canvas Context 2D is not supported in this browser.');
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222 |
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223 | return this._prepareResult(defaultColor);
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224 | }
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225 | }
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226 |
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227 | this._canvas.width = size.destWidth;
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228 | this._canvas.height = size.destHeight;
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229 |
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230 | try {
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231 | this._ctx.clearRect(0, 0, size.destWidth, size.destHeight);
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232 | this._ctx.drawImage(
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233 | resource,
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234 | size.srcLeft, size.srcTop,
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235 | size.srcWidth, size.srcHeight,
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236 | 0, 0,
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237 | size.destWidth, size.destHeight
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238 | );
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239 |
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240 | const bitmapData = this._ctx.getImageData(0, 0, size.destWidth, size.destHeight).data;
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241 | value = this.getColorFromArray4(bitmapData, options);
|
242 | } catch (e) {
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243 | this._outputError(options, `security error (CORS) for resource ${resource.src}.\nDetails: https://developer.mozilla.org/en/docs/Web/HTML/CORS_enabled_image`, e);
|
244 | }
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245 |
|
246 | return this._prepareResult(value);
|
247 | }
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248 |
|
249 | |
250 |
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251 |
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252 |
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253 |
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254 |
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255 |
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256 |
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257 |
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258 |
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259 |
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260 |
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261 | getColorFromArray4(arr, options) {
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262 | options = options || {};
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263 |
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264 | const
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265 | bytesPerPixel = 4,
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266 | arrLength = arr.length,
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267 | defaultColor = this._getDefaultColor(options);
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268 |
|
269 | if (arrLength < bytesPerPixel) {
|
270 | return defaultColor;
|
271 | }
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272 |
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273 | const
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274 | len = arrLength - arrLength % bytesPerPixel,
|
275 | step = (options.step || 1) * bytesPerPixel;
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276 |
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277 | let algorithm;
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278 |
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279 | switch (options.algorithm || 'sqrt') {
|
280 | case 'simple':
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281 | algorithm = simpleAlgorithm;
|
282 | break;
|
283 | case 'sqrt':
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284 | algorithm = sqrtAlgorithm;
|
285 | break;
|
286 | case 'dominant':
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287 | algorithm = dominantAlgorithm;
|
288 | break;
|
289 | default:
|
290 | throw Error(`${ERROR_PREFIX}${options.algorithm} is unknown algorithm.`);
|
291 | }
|
292 |
|
293 | return algorithm(arr, len, {
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294 | defaultColor,
|
295 | ignoredColor: options.ignoredColor,
|
296 | step
|
297 | });
|
298 | }
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299 |
|
300 | |
301 |
|
302 |
|
303 | destroy() {
|
304 | delete this._canvas;
|
305 | delete this._ctx;
|
306 | }
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307 |
|
308 | _getDefaultColor(options) {
|
309 | return this._getOption(options, 'defaultColor', [0, 0, 0, 0]);
|
310 | }
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311 |
|
312 | _getOption(options, name, defaultValue) {
|
313 | return typeof options[name] === 'undefined' ? defaultValue : options[name];
|
314 | }
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315 |
|
316 | _prepareSizeAndPosition(originalSize, options) {
|
317 | let
|
318 | srcLeft = this._getOption(options, 'left', 0),
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319 | srcTop = this._getOption(options, 'top', 0),
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320 | srcWidth = this._getOption(options, 'width', originalSize.width),
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321 | srcHeight = this._getOption(options, 'height', originalSize.height),
|
322 | destWidth = srcWidth,
|
323 | destHeight = srcHeight;
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324 |
|
325 | if (options.mode === 'precision') {
|
326 | return {
|
327 | srcLeft,
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328 | srcTop,
|
329 | srcWidth,
|
330 | srcHeight,
|
331 | destWidth,
|
332 | destHeight
|
333 | };
|
334 | }
|
335 |
|
336 | const
|
337 | maxSize = 100,
|
338 | minSize = 10;
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339 |
|
340 | let factor;
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341 |
|
342 | if (srcWidth > srcHeight) {
|
343 | factor = srcWidth / srcHeight;
|
344 | destWidth = maxSize;
|
345 | destHeight = Math.round(destWidth / factor);
|
346 | } else {
|
347 | factor = srcHeight / srcWidth;
|
348 | destHeight = maxSize;
|
349 | destWidth = Math.round(destHeight / factor);
|
350 | }
|
351 |
|
352 | if (
|
353 | destWidth > srcWidth || destHeight > srcHeight ||
|
354 | destWidth < minSize || destHeight < minSize
|
355 | ) {
|
356 | destWidth = srcWidth;
|
357 | destHeight = srcHeight;
|
358 | }
|
359 |
|
360 | return {
|
361 | srcLeft,
|
362 | srcTop,
|
363 | srcWidth,
|
364 | srcHeight,
|
365 | destWidth,
|
366 | destHeight
|
367 | };
|
368 | }
|
369 |
|
370 | _bindImageEvents(resource, options) {
|
371 | return new Promise((resolve, reject) => {
|
372 | const onload = () => {
|
373 | unbindEvents();
|
374 |
|
375 | const result = this.getColor(resource, options);
|
376 |
|
377 | if (result.error) {
|
378 | reject(result.error);
|
379 | } else {
|
380 | resolve(result);
|
381 | }
|
382 | },
|
383 | onerror = () => {
|
384 | unbindEvents();
|
385 |
|
386 | reject(Error(`${ERROR_PREFIX}Error loading image ${resource.src}.`));
|
387 | },
|
388 | onabort = () => {
|
389 | unbindEvents();
|
390 |
|
391 | reject(Error(`${ERROR_PREFIX}Image "${resource.src}" loading aborted.`));
|
392 | },
|
393 | unbindEvents = () => {
|
394 | resource.removeEventListener('load', onload);
|
395 | resource.removeEventListener('error', onerror);
|
396 | resource.removeEventListener('abort', onabort);
|
397 | };
|
398 |
|
399 | resource.addEventListener('load', onload);
|
400 | resource.addEventListener('error', onerror);
|
401 | resource.addEventListener('abort', onabort);
|
402 | });
|
403 | }
|
404 |
|
405 | _prepareResult(value) {
|
406 | const
|
407 | rgb = value.slice(0, 3),
|
408 | rgba = [].concat(rgb, value[3] / 255),
|
409 | isDark = this._isDark(value);
|
410 |
|
411 | return {
|
412 | value,
|
413 | rgb: 'rgb(' + rgb.join(',') + ')',
|
414 | rgba: 'rgba(' + rgba.join(',') + ')',
|
415 | hex: this._arrayToHex(rgb),
|
416 | hexa: this._arrayToHex(value),
|
417 | isDark,
|
418 | isLight: !isDark
|
419 | };
|
420 | }
|
421 |
|
422 | _getOriginalSize(resource) {
|
423 | if (resource instanceof HTMLImageElement) {
|
424 | return {
|
425 | width: resource.naturalWidth,
|
426 | height: resource.naturalHeight
|
427 | };
|
428 | }
|
429 |
|
430 | if (resource instanceof HTMLVideoElement) {
|
431 | return {
|
432 | width: resource.videoWidth,
|
433 | height: resource.videoHeight
|
434 | };
|
435 | }
|
436 |
|
437 | return {
|
438 | width: resource.width,
|
439 | height: resource.height
|
440 | };
|
441 | }
|
442 |
|
443 | _toHex(num) {
|
444 | let str = num.toString(16);
|
445 | return str.length === 1 ? '0' + str : str;
|
446 | }
|
447 |
|
448 | _arrayToHex(arr) {
|
449 | return '#' + arr.map(this._toHex).join('');
|
450 | }
|
451 |
|
452 | _isDark(color) {
|
453 |
|
454 | const result = (color[0] * 299 + color[1] * 587 + color[2] * 114) / 1000;
|
455 |
|
456 | return result < 128;
|
457 | }
|
458 |
|
459 | _makeCanvas() {
|
460 | return typeof window === 'undefined' ?
|
461 | new OffscreenCanvas(1, 1) :
|
462 | document.createElement('canvas');
|
463 | }
|
464 |
|
465 | _outputError(options, error, details) {
|
466 | if (!options.silent) {
|
467 | console.error(`${ERROR_PREFIX}${error}`);
|
468 |
|
469 | if (details) {
|
470 | console.error(details);
|
471 | }
|
472 | }
|
473 | }
|
474 | }
|
475 |
|
476 | export default FastAverageColor;
|