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 "platform/graphics/Color.h" 28 29 #include "wtf/Assertions.h" 30 #include "wtf/DecimalNumber.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 template <typename CharacterType> 128 static inline bool parseHexColorInternal(const CharacterType* name, unsigned length, RGBA32& rgb) 129 { 130 if (length != 3 && length != 6) 131 return false; 132 unsigned value = 0; 133 for (unsigned i = 0; i < length; ++i) { 134 if (!isASCIIHexDigit(name[i])) 135 return false; 136 value <<= 4; 137 value |= toASCIIHexValue(name[i]); 138 } 139 if (length == 6) { 140 rgb = 0xFF000000 | value; 141 return true; 142 } 143 // #abc converts to #aabbcc 144 rgb = 0xFF000000 145 | (value & 0xF00) << 12 | (value & 0xF00) << 8 146 | (value & 0xF0) << 8 | (value & 0xF0) << 4 147 | (value & 0xF) << 4 | (value & 0xF); 148 return true; 149 } 150 151 bool Color::parseHexColor(const LChar* name, unsigned length, RGBA32& rgb) 152 { 153 return parseHexColorInternal(name, length, rgb); 154 } 155 156 bool Color::parseHexColor(const UChar* name, unsigned length, RGBA32& rgb) 157 { 158 return parseHexColorInternal(name, length, rgb); 159 } 160 161 bool Color::parseHexColor(const String& name, RGBA32& rgb) 162 { 163 unsigned length = name.length(); 164 165 if (!length) 166 return false; 167 if (name.is8Bit()) 168 return parseHexColor(name.characters8(), name.length(), rgb); 169 return parseHexColor(name.characters16(), name.length(), rgb); 170 } 171 172 int differenceSquared(const Color& c1, const Color& c2) 173 { 174 int dR = c1.red() - c2.red(); 175 int dG = c1.green() - c2.green(); 176 int dB = c1.blue() - c2.blue(); 177 return dR * dR + dG * dG + dB * dB; 178 } 179 180 Color::Color(const String& name) 181 { 182 if (name[0] == '#') { 183 if (name.is8Bit()) 184 m_valid = parseHexColor(name.characters8() + 1, name.length() - 1, m_color); 185 else 186 m_valid = parseHexColor(name.characters16() + 1, name.length() - 1, m_color); 187 } else { 188 setNamedColor(name); 189 } 190 } 191 192 Color::Color(const char* name) 193 { 194 if (name[0] == '#') { 195 m_valid = parseHexColor(&name[1], m_color); 196 } else { 197 const NamedColor* foundColor = findColor(name, strlen(name)); 198 m_color = foundColor ? foundColor->ARGBValue : 0; 199 m_valid = foundColor; 200 } 201 } 202 203 String Color::serialized() const 204 { 205 if (!hasAlpha()) { 206 StringBuilder builder; 207 builder.reserveCapacity(7); 208 builder.append('#'); 209 appendByteAsHex(red(), builder, Lowercase); 210 appendByteAsHex(green(), builder, Lowercase); 211 appendByteAsHex(blue(), builder, Lowercase); 212 return builder.toString(); 213 } 214 215 StringBuilder result; 216 result.reserveCapacity(28); 217 const char commaSpace[] = ", "; 218 const char rgbaParen[] = "rgba("; 219 220 result.append(rgbaParen, 5); 221 result.appendNumber(red()); 222 result.append(commaSpace, 2); 223 result.appendNumber(green()); 224 result.append(commaSpace, 2); 225 result.appendNumber(blue()); 226 result.append(commaSpace, 2); 227 228 if (!alpha()) 229 result.append('0'); 230 else { 231 NumberToLStringBuffer buffer; 232 unsigned length = DecimalNumber(alpha() / 255.0).toStringDecimal(buffer, WTF::NumberToStringBufferLength); 233 result.append(buffer, length); 234 } 235 236 result.append(')'); 237 return result.toString(); 238 } 239 240 String Color::nameForRenderTreeAsText() const 241 { 242 if (alpha() < 0xFF) 243 return String::format("#%02X%02X%02X%02X", red(), green(), blue(), alpha()); 244 return String::format("#%02X%02X%02X", red(), green(), blue()); 245 } 246 247 static inline const NamedColor* findNamedColor(const String& name) 248 { 249 char buffer[64]; // easily big enough for the longest color name 250 unsigned length = name.length(); 251 if (length > sizeof(buffer) - 1) 252 return 0; 253 for (unsigned i = 0; i < length; ++i) { 254 UChar c = name[i]; 255 if (!c || c > 0x7F) 256 return 0; 257 buffer[i] = toASCIILower(static_cast<char>(c)); 258 } 259 buffer[length] = '\0'; 260 return findColor(buffer, length); 261 } 262 263 void Color::setNamedColor(const String& name) 264 { 265 const NamedColor* foundColor = findNamedColor(name); 266 m_color = foundColor ? foundColor->ARGBValue : 0; 267 m_valid = foundColor; 268 } 269 270 Color Color::light() const 271 { 272 // Hardcode this common case for speed. 273 if (m_color == black) 274 return lightenedBlack; 275 276 const float scaleFactor = nextafterf(256.0f, 0.0f); 277 278 float r, g, b, a; 279 getRGBA(r, g, b, a); 280 281 float v = max(r, max(g, b)); 282 283 if (v == 0.0f) 284 // Lightened black with alpha. 285 return Color(0x54, 0x54, 0x54, alpha()); 286 287 float multiplier = min(1.0f, v + 0.33f) / v; 288 289 return Color(static_cast<int>(multiplier * r * scaleFactor), 290 static_cast<int>(multiplier * g * scaleFactor), 291 static_cast<int>(multiplier * b * scaleFactor), 292 alpha()); 293 } 294 295 Color Color::dark() const 296 { 297 // Hardcode this common case for speed. 298 if (m_color == white) 299 return darkenedWhite; 300 301 const float scaleFactor = nextafterf(256.0f, 0.0f); 302 303 float r, g, b, a; 304 getRGBA(r, g, b, a); 305 306 float v = max(r, max(g, b)); 307 float multiplier = max(0.0f, (v - 0.33f) / v); 308 309 return Color(static_cast<int>(multiplier * r * scaleFactor), 310 static_cast<int>(multiplier * g * scaleFactor), 311 static_cast<int>(multiplier * b * scaleFactor), 312 alpha()); 313 } 314 315 static int blendComponent(int c, int a) 316 { 317 // We use white. 318 float alpha = a / 255.0f; 319 int whiteBlend = 255 - a; 320 c -= whiteBlend; 321 return static_cast<int>(c / alpha); 322 } 323 324 const int cStartAlpha = 153; // 60% 325 const int cEndAlpha = 204; // 80%; 326 const int cAlphaIncrement = 17; // Increments in between. 327 328 Color Color::blend(const Color& source) const 329 { 330 if (!alpha() || !source.hasAlpha()) 331 return source; 332 333 if (!source.alpha()) 334 return *this; 335 336 int d = 255 * (alpha() + source.alpha()) - alpha() * source.alpha(); 337 int a = d / 255; 338 int r = (red() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.red()) / d; 339 int g = (green() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.green()) / d; 340 int b = (blue() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.blue()) / d; 341 return Color(r, g, b, a); 342 } 343 344 Color Color::blendWithWhite() const 345 { 346 // If the color contains alpha already, we leave it alone. 347 if (hasAlpha()) 348 return *this; 349 350 Color newColor; 351 for (int alpha = cStartAlpha; alpha <= cEndAlpha; alpha += cAlphaIncrement) { 352 // We have a solid color. Convert to an equivalent color that looks the same when blended with white 353 // at the current alpha. Try using less transparency if the numbers end up being negative. 354 int r = blendComponent(red(), alpha); 355 int g = blendComponent(green(), alpha); 356 int b = blendComponent(blue(), alpha); 357 358 newColor = Color(r, g, b, alpha); 359 360 if (r >= 0 && g >= 0 && b >= 0) 361 break; 362 } 363 return newColor; 364 } 365 366 void Color::getRGBA(float& r, float& g, float& b, float& a) const 367 { 368 r = red() / 255.0f; 369 g = green() / 255.0f; 370 b = blue() / 255.0f; 371 a = alpha() / 255.0f; 372 } 373 374 void Color::getRGBA(double& r, double& g, double& b, double& a) const 375 { 376 r = red() / 255.0; 377 g = green() / 255.0; 378 b = blue() / 255.0; 379 a = alpha() / 255.0; 380 } 381 382 void Color::getHSL(double& hue, double& saturation, double& lightness) const 383 { 384 // http://en.wikipedia.org/wiki/HSL_color_space. This is a direct copy of 385 // the algorithm therein, although it's 360^o based and we end up wanting 386 // [0...1) based. It's clearer if we stick to 360^o until the end. 387 double r = static_cast<double>(red()) / 255.0; 388 double g = static_cast<double>(green()) / 255.0; 389 double b = static_cast<double>(blue()) / 255.0; 390 double max = std::max(std::max(r, g), b); 391 double min = std::min(std::min(r, g), b); 392 393 if (max == min) 394 hue = 0.0; 395 else if (max == r) 396 hue = (60.0 * ((g - b) / (max - min))) + 360.0; 397 else if (max == g) 398 hue = (60.0 * ((b - r) / (max - min))) + 120.0; 399 else 400 hue = (60.0 * ((r - g) / (max - min))) + 240.0; 401 402 if (hue >= 360.0) 403 hue -= 360.0; 404 405 // makeRGBAFromHSLA assumes that hue is in [0...1). 406 hue /= 360.0; 407 408 lightness = 0.5 * (max + min); 409 if (max == min) 410 saturation = 0.0; 411 else if (lightness <= 0.5) 412 saturation = ((max - min) / (max + min)); 413 else 414 saturation = ((max - min) / (2.0 - (max + min))); 415 } 416 417 Color colorFromPremultipliedARGB(RGBA32 pixelColor) 418 { 419 int alpha = alphaChannel(pixelColor); 420 if (alpha && alpha < 255) { 421 return Color::createUnchecked( 422 redChannel(pixelColor) * 255 / alpha, 423 greenChannel(pixelColor) * 255 / alpha, 424 blueChannel(pixelColor) * 255 / alpha, 425 alpha); 426 } else 427 return Color(pixelColor); 428 } 429 430 RGBA32 premultipliedARGBFromColor(const Color& color) 431 { 432 unsigned pixelColor; 433 434 unsigned alpha = color.alpha(); 435 if (alpha < 255) { 436 pixelColor = Color::createUnchecked( 437 (color.red() * alpha + 254) / 255, 438 (color.green() * alpha + 254) / 255, 439 (color.blue() * alpha + 254) / 255, 440 alpha).rgb(); 441 } else 442 pixelColor = color.rgb(); 443 444 return pixelColor; 445 } 446 447 } // namespace WebCore 448
