1 /* 2 * Copyright (C) 2003, 2004, 2005, 2006, 2008 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "config.h" 27 #include "Color.h" 28 29 #include "HashTools.h" 30 #include <wtf/Assertions.h> 31 #include <wtf/HexNumber.h> 32 #include <wtf/MathExtras.h> 33 #include <wtf/text/StringBuilder.h> 34 35 using namespace std; 36 37 namespace WebCore { 38 39 #if !COMPILER(MSVC) 40 const RGBA32 Color::black; 41 const RGBA32 Color::white; 42 const RGBA32 Color::darkGray; 43 const RGBA32 Color::gray; 44 const RGBA32 Color::lightGray; 45 const RGBA32 Color::transparent; 46 #endif 47 48 static const RGBA32 lightenedBlack = 0xFF545454; 49 static const RGBA32 darkenedWhite = 0xFFABABAB; 50 51 RGBA32 makeRGB(int r, int g, int b) 52 { 53 return 0xFF000000 | max(0, min(r, 255)) << 16 | max(0, min(g, 255)) << 8 | max(0, min(b, 255)); 54 } 55 56 RGBA32 makeRGBA(int r, int g, int b, int a) 57 { 58 return max(0, min(a, 255)) << 24 | max(0, min(r, 255)) << 16 | max(0, min(g, 255)) << 8 | max(0, min(b, 255)); 59 } 60 61 static int colorFloatToRGBAByte(float f) 62 { 63 // We use lroundf and 255 instead of nextafterf(256, 0) to match CG's rounding 64 return max(0, min(static_cast<int>(lroundf(255.0f * f)), 255)); 65 } 66 67 RGBA32 makeRGBA32FromFloats(float r, float g, float b, float a) 68 { 69 return colorFloatToRGBAByte(a) << 24 | colorFloatToRGBAByte(r) << 16 | colorFloatToRGBAByte(g) << 8 | colorFloatToRGBAByte(b); 70 } 71 72 RGBA32 colorWithOverrideAlpha(RGBA32 color, float overrideAlpha) 73 { 74 RGBA32 rgbOnly = color & 0x00FFFFFF; 75 RGBA32 rgba = rgbOnly | colorFloatToRGBAByte(overrideAlpha) << 24; 76 return rgba; 77 } 78 79 static double calcHue(double temp1, double temp2, double hueVal) 80 { 81 if (hueVal < 0.0) 82 hueVal++; 83 else if (hueVal > 1.0) 84 hueVal--; 85 if (hueVal * 6.0 < 1.0) 86 return temp1 + (temp2 - temp1) * hueVal * 6.0; 87 if (hueVal * 2.0 < 1.0) 88 return temp2; 89 if (hueVal * 3.0 < 2.0) 90 return temp1 + (temp2 - temp1) * (2.0 / 3.0 - hueVal) * 6.0; 91 return temp1; 92 } 93 94 // Explanation of this algorithm can be found in the CSS3 Color Module 95 // specification at http://www.w3.org/TR/css3-color/#hsl-color with further 96 // explanation available at http://en.wikipedia.org/wiki/HSL_color_space 97 98 // all values are in the range of 0 to 1.0 99 RGBA32 makeRGBAFromHSLA(double hue, double saturation, double lightness, double alpha) 100 { 101 const double scaleFactor = nextafter(256.0, 0.0); 102 103 if (!saturation) { 104 int greyValue = static_cast<int>(lightness * scaleFactor); 105 return makeRGBA(greyValue, greyValue, greyValue, static_cast<int>(alpha * scaleFactor)); 106 } 107 108 double temp2 = lightness < 0.5 ? lightness * (1.0 + saturation) : lightness + saturation - lightness * saturation; 109 double temp1 = 2.0 * lightness - temp2; 110 111 return makeRGBA(static_cast<int>(calcHue(temp1, temp2, hue + 1.0 / 3.0) * scaleFactor), 112 static_cast<int>(calcHue(temp1, temp2, hue) * scaleFactor), 113 static_cast<int>(calcHue(temp1, temp2, hue - 1.0 / 3.0) * scaleFactor), 114 static_cast<int>(alpha * scaleFactor)); 115 } 116 117 RGBA32 makeRGBAFromCMYKA(float c, float m, float y, float k, float a) 118 { 119 double colors = 1 - k; 120 int r = static_cast<int>(nextafter(256, 0) * (colors * (1 - c))); 121 int g = static_cast<int>(nextafter(256, 0) * (colors * (1 - m))); 122 int b = static_cast<int>(nextafter(256, 0) * (colors * (1 - y))); 123 return makeRGBA(r, g, b, static_cast<float>(nextafter(256, 0) * a)); 124 } 125 126 // originally moved here from the CSS parser 127 bool Color::parseHexColor(const UChar* name, unsigned length, RGBA32& rgb) 128 { 129 if (length != 3 && length != 6) 130 return false; 131 unsigned value = 0; 132 for (unsigned i = 0; i < length; ++i) { 133 if (!isASCIIHexDigit(name[i])) 134 return false; 135 value <<= 4; 136 value |= toASCIIHexValue(name[i]); 137 } 138 if (length == 6) { 139 rgb = 0xFF000000 | value; 140 return true; 141 } 142 // #abc converts to #aabbcc 143 rgb = 0xFF000000 144 | (value & 0xF00) << 12 | (value & 0xF00) << 8 145 | (value & 0xF0) << 8 | (value & 0xF0) << 4 146 | (value & 0xF) << 4 | (value & 0xF); 147 return true; 148 } 149 150 bool Color::parseHexColor(const String& name, RGBA32& rgb) 151 { 152 return parseHexColor(name.characters(), name.length(), rgb); 153 } 154 155 int differenceSquared(const Color& c1, const Color& c2) 156 { 157 int dR = c1.red() - c2.red(); 158 int dG = c1.green() - c2.green(); 159 int dB = c1.blue() - c2.blue(); 160 return dR * dR + dG * dG + dB * dB; 161 } 162 163 Color::Color(const String& name) 164 { 165 if (name[0] == '#') 166 m_valid = parseHexColor(name.characters() + 1, name.length() - 1, m_color); 167 else 168 setNamedColor(name); 169 } 170 171 Color::Color(const char* name) 172 { 173 if (name[0] == '#') 174 m_valid = parseHexColor(&name[1], m_color); 175 else { 176 const NamedColor* foundColor = findColor(name, strlen(name)); 177 m_color = foundColor ? foundColor->ARGBValue : 0; 178 m_valid = foundColor; 179 } 180 } 181 182 String Color::serialized() const 183 { 184 DEFINE_STATIC_LOCAL(const String, commaSpace, (", ")); 185 DEFINE_STATIC_LOCAL(const String, rgbaParen, ("rgba(")); 186 DEFINE_STATIC_LOCAL(const String, zeroPointZero, ("0.0")); 187 188 if (!hasAlpha()) { 189 StringBuilder builder; 190 builder.reserveCapacity(7); 191 builder.append('#'); 192 appendByteAsHex(red(), builder, Lowercase); 193 appendByteAsHex(green(), builder, Lowercase); 194 appendByteAsHex(blue(), builder, Lowercase); 195 return builder.toString(); 196 } 197 198 Vector<UChar> result; 199 result.reserveInitialCapacity(28); 200 201 append(result, rgbaParen); 202 appendNumber(result, red()); 203 append(result, commaSpace); 204 appendNumber(result, green()); 205 append(result, commaSpace); 206 appendNumber(result, blue()); 207 append(result, commaSpace); 208 209 // Match Gecko ("0.0" for zero, 5 decimals for anything else) 210 if (!alpha()) 211 append(result, zeroPointZero); 212 else 213 append(result, String::format("%.5f", alpha() / 255.0f)); 214 215 result.append(')'); 216 return String::adopt(result); 217 } 218 219 String Color::nameForRenderTreeAsText() const 220 { 221 if (alpha() < 0xFF) 222 return String::format("#%02X%02X%02X%02X", red(), green(), blue(), alpha()); 223 return String::format("#%02X%02X%02X", red(), green(), blue()); 224 } 225 226 static inline const NamedColor* findNamedColor(const String& name) 227 { 228 char buffer[64]; // easily big enough for the longest color name 229 unsigned length = name.length(); 230 if (length > sizeof(buffer) - 1) 231 return 0; 232 for (unsigned i = 0; i < length; ++i) { 233 UChar c = name[i]; 234 if (!c || c > 0x7F) 235 return 0; 236 buffer[i] = toASCIILower(static_cast<char>(c)); 237 } 238 buffer[length] = '\0'; 239 return findColor(buffer, length); 240 } 241 242 void Color::setNamedColor(const String& name) 243 { 244 const NamedColor* foundColor = findNamedColor(name); 245 m_color = foundColor ? foundColor->ARGBValue : 0; 246 m_valid = foundColor; 247 } 248 249 Color Color::light() const 250 { 251 // Hardcode this common case for speed. 252 if (m_color == black) 253 return lightenedBlack; 254 255 const float scaleFactor = nextafterf(256.0f, 0.0f); 256 257 float r, g, b, a; 258 getRGBA(r, g, b, a); 259 260 float v = max(r, max(g, b)); 261 262 if (v == 0.0f) 263 // Lightened black with alpha. 264 return Color(0x54, 0x54, 0x54, alpha()); 265 266 float multiplier = min(1.0f, v + 0.33f) / v; 267 268 return Color(static_cast<int>(multiplier * r * scaleFactor), 269 static_cast<int>(multiplier * g * scaleFactor), 270 static_cast<int>(multiplier * b * scaleFactor), 271 alpha()); 272 } 273 274 Color Color::dark() const 275 { 276 // Hardcode this common case for speed. 277 if (m_color == white) 278 return darkenedWhite; 279 280 const float scaleFactor = nextafterf(256.0f, 0.0f); 281 282 float r, g, b, a; 283 getRGBA(r, g, b, a); 284 285 float v = max(r, max(g, b)); 286 float multiplier = max(0.0f, (v - 0.33f) / v); 287 288 return Color(static_cast<int>(multiplier * r * scaleFactor), 289 static_cast<int>(multiplier * g * scaleFactor), 290 static_cast<int>(multiplier * b * scaleFactor), 291 alpha()); 292 } 293 294 static int blendComponent(int c, int a) 295 { 296 // We use white. 297 float alpha = a / 255.0f; 298 int whiteBlend = 255 - a; 299 c -= whiteBlend; 300 return static_cast<int>(c / alpha); 301 } 302 303 const int cStartAlpha = 153; // 60% 304 const int cEndAlpha = 204; // 80%; 305 const int cAlphaIncrement = 17; // Increments in between. 306 307 Color Color::blend(const Color& source) const 308 { 309 if (!alpha() || !source.hasAlpha()) 310 return source; 311 312 if (!source.alpha()) 313 return *this; 314 315 int d = 255 * (alpha() + source.alpha()) - alpha() * source.alpha(); 316 int a = d / 255; 317 int r = (red() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.red()) / d; 318 int g = (green() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.green()) / d; 319 int b = (blue() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.blue()) / d; 320 return Color(r, g, b, a); 321 } 322 323 Color Color::blendWithWhite() const 324 { 325 // If the color contains alpha already, we leave it alone. 326 if (hasAlpha()) 327 return *this; 328 329 Color newColor; 330 for (int alpha = cStartAlpha; alpha <= cEndAlpha; alpha += cAlphaIncrement) { 331 // We have a solid color. Convert to an equivalent color that looks the same when blended with white 332 // at the current alpha. Try using less transparency if the numbers end up being negative. 333 int r = blendComponent(red(), alpha); 334 int g = blendComponent(green(), alpha); 335 int b = blendComponent(blue(), alpha); 336 337 newColor = Color(r, g, b, alpha); 338 339 if (r >= 0 && g >= 0 && b >= 0) 340 break; 341 } 342 return newColor; 343 } 344 345 void Color::getRGBA(float& r, float& g, float& b, float& a) const 346 { 347 r = red() / 255.0f; 348 g = green() / 255.0f; 349 b = blue() / 255.0f; 350 a = alpha() / 255.0f; 351 } 352 353 void Color::getRGBA(double& r, double& g, double& b, double& a) const 354 { 355 r = red() / 255.0; 356 g = green() / 255.0; 357 b = blue() / 255.0; 358 a = alpha() / 255.0; 359 } 360 361 void Color::getHSL(double& hue, double& saturation, double& lightness) const 362 { 363 // http://en.wikipedia.org/wiki/HSL_color_space. This is a direct copy of 364 // the algorithm therein, although it's 360^o based and we end up wanting 365 // [0...1) based. It's clearer if we stick to 360^o until the end. 366 double r = static_cast<double>(red()) / 255.0; 367 double g = static_cast<double>(green()) / 255.0; 368 double b = static_cast<double>(blue()) / 255.0; 369 double max = std::max(std::max(r, g), b); 370 double min = std::min(std::min(r, g), b); 371 372 if (max == min) 373 hue = 0.0; 374 else if (max == r) 375 hue = (60.0 * ((g - b) / (max - min))) + 360.0; 376 else if (max == g) 377 hue = (60.0 * ((b - r) / (max - min))) + 120.0; 378 else 379 hue = (60.0 * ((r - g) / (max - min))) + 240.0; 380 381 if (hue >= 360.0) 382 hue -= 360.0; 383 384 // makeRGBAFromHSLA assumes that hue is in [0...1). 385 hue /= 360.0; 386 387 lightness = 0.5 * (max + min); 388 if (max == min) 389 saturation = 0.0; 390 else if (lightness <= 0.5) 391 saturation = ((max - min) / (max + min)); 392 else 393 saturation = ((max - min) / (2.0 - (max + min))); 394 } 395 396 Color colorFromPremultipliedARGB(unsigned pixelColor) 397 { 398 RGBA32 rgba; 399 400 if (unsigned alpha = (pixelColor & 0xFF000000) >> 24) { 401 rgba = makeRGBA(((pixelColor & 0x00FF0000) >> 16) * 255 / alpha, 402 ((pixelColor & 0x0000FF00) >> 8) * 255 / alpha, 403 (pixelColor & 0x000000FF) * 255 / alpha, 404 alpha); 405 } else 406 rgba = pixelColor; 407 408 return Color(rgba); 409 } 410 411 unsigned premultipliedARGBFromColor(const Color& color) 412 { 413 unsigned pixelColor; 414 415 if (unsigned alpha = color.alpha()) { 416 pixelColor = alpha << 24 | 417 ((color.red() * alpha + 254) / 255) << 16 | 418 ((color.green() * alpha + 254) / 255) << 8 | 419 ((color.blue() * alpha + 254) / 255); 420 } else 421 pixelColor = color.rgb(); 422 423 return pixelColor; 424 } 425 426 } // namespace WebCore 427
