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 "PlatformString.h" 30 #include <math.h> 31 #include <wtf/Assertions.h> 32 #include <wtf/MathExtras.h> 33 34 #include "ColorData.c" 35 36 using namespace std; 37 using namespace WTF; 38 39 namespace WebCore { 40 41 #if !COMPILER(MSVC) 42 const RGBA32 Color::black; 43 const RGBA32 Color::white; 44 const RGBA32 Color::darkGray; 45 const RGBA32 Color::gray; 46 const RGBA32 Color::lightGray; 47 const RGBA32 Color::transparent; 48 #endif 49 50 static const RGBA32 lightenedBlack = 0xFF545454; 51 static const RGBA32 darkenedWhite = 0xFFABABAB; 52 53 RGBA32 makeRGB(int r, int g, int b) 54 { 55 return 0xFF000000 | max(0, min(r, 255)) << 16 | max(0, min(g, 255)) << 8 | max(0, min(b, 255)); 56 } 57 58 RGBA32 makeRGBA(int r, int g, int b, int a) 59 { 60 return max(0, min(a, 255)) << 24 | max(0, min(r, 255)) << 16 | max(0, min(g, 255)) << 8 | max(0, min(b, 255)); 61 } 62 63 static int colorFloatToRGBAByte(float f) 64 { 65 // We use lroundf and 255 instead of nextafterf(256, 0) to match CG's rounding 66 return max(0, min(static_cast<int>(lroundf(255.0f * f)), 255)); 67 } 68 69 RGBA32 makeRGBA32FromFloats(float r, float g, float b, float a) 70 { 71 return colorFloatToRGBAByte(a) << 24 | colorFloatToRGBAByte(r) << 16 | colorFloatToRGBAByte(g) << 8 | colorFloatToRGBAByte(b); 72 } 73 74 RGBA32 colorWithOverrideAlpha(RGBA32 color, float overrideAlpha) 75 { 76 RGBA32 rgbOnly = color & 0x00FFFFFF; 77 RGBA32 rgba = rgbOnly | colorFloatToRGBAByte(overrideAlpha) << 24; 78 return rgba; 79 } 80 81 static double calcHue(double temp1, double temp2, double hueVal) 82 { 83 if (hueVal < 0.0) 84 hueVal++; 85 else if (hueVal > 1.0) 86 hueVal--; 87 if (hueVal * 6.0 < 1.0) 88 return temp1 + (temp2 - temp1) * hueVal * 6.0; 89 if (hueVal * 2.0 < 1.0) 90 return temp2; 91 if (hueVal * 3.0 < 2.0) 92 return temp1 + (temp2 - temp1) * (2.0 / 3.0 - hueVal) * 6.0; 93 return temp1; 94 } 95 96 // Explanation of this algorithm can be found in the CSS3 Color Module 97 // specification at http://www.w3.org/TR/css3-color/#hsl-color with further 98 // explanation available at http://en.wikipedia.org/wiki/HSL_color_space 99 100 // all values are in the range of 0 to 1.0 101 RGBA32 makeRGBAFromHSLA(double hue, double saturation, double lightness, double alpha) 102 { 103 const double scaleFactor = nextafter(256.0, 0.0); 104 105 if (!saturation) { 106 int greyValue = static_cast<int>(lightness * scaleFactor); 107 return makeRGBA(greyValue, greyValue, greyValue, static_cast<int>(alpha * scaleFactor)); 108 } 109 110 double temp2 = lightness < 0.5 ? lightness * (1.0 + saturation) : lightness + saturation - lightness * saturation; 111 double temp1 = 2.0 * lightness - temp2; 112 113 return makeRGBA(static_cast<int>(calcHue(temp1, temp2, hue + 1.0 / 3.0) * scaleFactor), 114 static_cast<int>(calcHue(temp1, temp2, hue) * scaleFactor), 115 static_cast<int>(calcHue(temp1, temp2, hue - 1.0 / 3.0) * scaleFactor), 116 static_cast<int>(alpha * scaleFactor)); 117 } 118 119 RGBA32 makeRGBAFromCMYKA(float c, float m, float y, float k, float a) 120 { 121 double colors = 1 - k; 122 int r = static_cast<int>(nextafter(256, 0) * (colors * (1 - c))); 123 int g = static_cast<int>(nextafter(256, 0) * (colors * (1 - m))); 124 int b = static_cast<int>(nextafter(256, 0) * (colors * (1 - y))); 125 return makeRGBA(r, g, b, static_cast<float>(nextafter(256, 0) * a)); 126 } 127 128 // originally moved here from the CSS parser 129 bool Color::parseHexColor(const String& name, RGBA32& rgb) 130 { 131 unsigned length = name.length(); 132 if (length != 3 && length != 6) 133 return false; 134 unsigned value = 0; 135 for (unsigned i = 0; i < length; ++i) { 136 if (!isASCIIHexDigit(name[i])) 137 return false; 138 value <<= 4; 139 value |= toASCIIHexValue(name[i]); 140 } 141 if (length == 6) { 142 rgb = 0xFF000000 | value; 143 return true; 144 } 145 // #abc converts to #aabbcc 146 rgb = 0xFF000000 147 | (value & 0xF00) << 12 | (value & 0xF00) << 8 148 | (value & 0xF0) << 8 | (value & 0xF0) << 4 149 | (value & 0xF) << 4 | (value & 0xF); 150 return true; 151 } 152 153 int differenceSquared(const Color& c1, const Color& c2) 154 { 155 int dR = c1.red() - c2.red(); 156 int dG = c1.green() - c2.green(); 157 int dB = c1.blue() - c2.blue(); 158 return dR * dR + dG * dG + dB * dB; 159 } 160 161 Color::Color(const String& name) 162 { 163 if (name.startsWith("#")) 164 m_valid = parseHexColor(name.substring(1), m_color); 165 else 166 setNamedColor(name); 167 } 168 169 Color::Color(const char* name) 170 { 171 if (name[0] == '#') 172 m_valid = parseHexColor(&name[1], m_color); 173 else { 174 const NamedColor* foundColor = findColor(name, strlen(name)); 175 m_color = foundColor ? foundColor->RGBValue : 0; 176 m_color |= 0xFF000000; 177 m_valid = foundColor; 178 } 179 } 180 181 String Color::name() const 182 { 183 if (alpha() < 0xFF) 184 return String::format("#%02X%02X%02X%02X", red(), green(), blue(), alpha()); 185 return String::format("#%02X%02X%02X", red(), green(), blue()); 186 } 187 188 static inline const NamedColor* findNamedColor(const String& name) 189 { 190 char buffer[64]; // easily big enough for the longest color name 191 unsigned length = name.length(); 192 if (length > sizeof(buffer) - 1) 193 return 0; 194 for (unsigned i = 0; i < length; ++i) { 195 UChar c = name[i]; 196 if (!c || c > 0x7F) 197 return 0; 198 buffer[i] = toASCIILower(static_cast<char>(c)); 199 } 200 buffer[length] = '\0'; 201 return findColor(buffer, length); 202 } 203 204 void Color::setNamedColor(const String& name) 205 { 206 const NamedColor* foundColor = findNamedColor(name); 207 m_color = foundColor ? foundColor->RGBValue : 0; 208 m_color |= 0xFF000000; 209 m_valid = foundColor; 210 } 211 212 Color Color::light() const 213 { 214 // Hardcode this common case for speed. 215 if (m_color == black) 216 return lightenedBlack; 217 218 const float scaleFactor = nextafterf(256.0f, 0.0f); 219 220 float r, g, b, a; 221 getRGBA(r, g, b, a); 222 223 float v = max(r, max(g, b)); 224 225 if (v == 0.0f) 226 // Lightened black with alpha. 227 return Color(0x54, 0x54, 0x54, alpha()); 228 229 float multiplier = min(1.0f, v + 0.33f) / v; 230 231 return Color(static_cast<int>(multiplier * r * scaleFactor), 232 static_cast<int>(multiplier * g * scaleFactor), 233 static_cast<int>(multiplier * b * scaleFactor), 234 alpha()); 235 } 236 237 Color Color::dark() const 238 { 239 // Hardcode this common case for speed. 240 if (m_color == white) 241 return darkenedWhite; 242 243 const float scaleFactor = nextafterf(256.0f, 0.0f); 244 245 float r, g, b, a; 246 getRGBA(r, g, b, a); 247 248 float v = max(r, max(g, b)); 249 float multiplier = max(0.0f, (v - 0.33f) / v); 250 251 return Color(static_cast<int>(multiplier * r * scaleFactor), 252 static_cast<int>(multiplier * g * scaleFactor), 253 static_cast<int>(multiplier * b * scaleFactor), 254 alpha()); 255 } 256 257 static int blendComponent(int c, int a) 258 { 259 // We use white. 260 float alpha = a / 255.0f; 261 int whiteBlend = 255 - a; 262 c -= whiteBlend; 263 return static_cast<int>(c / alpha); 264 } 265 266 const int cStartAlpha = 153; // 60% 267 const int cEndAlpha = 204; // 80%; 268 const int cAlphaIncrement = 17; // Increments in between. 269 270 Color Color::blend(const Color& source) const 271 { 272 if (!alpha() || !source.hasAlpha()) 273 return source; 274 275 if (!source.alpha()) 276 return *this; 277 278 int d = 255 * (alpha() + source.alpha()) - alpha() * source.alpha(); 279 int a = d / 255; 280 int r = (red() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.red()) / d; 281 int g = (green() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.green()) / d; 282 int b = (blue() * alpha() * (255 - source.alpha()) + 255 * source.alpha() * source.blue()) / d; 283 return Color(r, g, b, a); 284 } 285 286 Color Color::blendWithWhite() const 287 { 288 // If the color contains alpha already, we leave it alone. 289 if (hasAlpha()) 290 return *this; 291 292 Color newColor; 293 for (int alpha = cStartAlpha; alpha <= cEndAlpha; alpha += cAlphaIncrement) { 294 // We have a solid color. Convert to an equivalent color that looks the same when blended with white 295 // at the current alpha. Try using less transparency if the numbers end up being negative. 296 int r = blendComponent(red(), alpha); 297 int g = blendComponent(green(), alpha); 298 int b = blendComponent(blue(), alpha); 299 300 newColor = Color(r, g, b, alpha); 301 302 if (r >= 0 && g >= 0 && b >= 0) 303 break; 304 } 305 return newColor; 306 } 307 308 void Color::getRGBA(float& r, float& g, float& b, float& a) const 309 { 310 r = red() / 255.0f; 311 g = green() / 255.0f; 312 b = blue() / 255.0f; 313 a = alpha() / 255.0f; 314 } 315 316 void Color::getRGBA(double& r, double& g, double& b, double& a) const 317 { 318 r = red() / 255.0; 319 g = green() / 255.0; 320 b = blue() / 255.0; 321 a = alpha() / 255.0; 322 } 323 324 void Color::getHSL(double& hue, double& saturation, double& lightness) const 325 { 326 // http://en.wikipedia.org/wiki/HSL_color_space. This is a direct copy of 327 // the algorithm therein, although it's 360^o based and we end up wanting 328 // [0...1) based. It's clearer if we stick to 360^o until the end. 329 double r = static_cast<double>(red()) / 255.0; 330 double g = static_cast<double>(green()) / 255.0; 331 double b = static_cast<double>(blue()) / 255.0; 332 double max = std::max(std::max(r, g), b); 333 double min = std::min(std::min(r, g), b); 334 335 if (max == min) 336 hue = 0.0; 337 else if (max == r) 338 hue = (60.0 * ((g - b) / (max - min))) + 360.0; 339 else if (max == g) 340 hue = (60.0 * ((b - r) / (max - min))) + 120.0; 341 else 342 hue = (60.0 * ((r - g) / (max - min))) + 240.0; 343 344 if (hue >= 360.0) 345 hue -= 360.0; 346 347 // makeRGBAFromHSLA assumes that hue is in [0...1). 348 hue /= 360.0; 349 350 lightness = 0.5 * (max + min); 351 if (max == min) 352 saturation = 0.0; 353 else if (lightness <= 0.5) 354 saturation = ((max - min) / (max + min)); 355 else 356 saturation = ((max - min) / (2.0 - (max + min))); 357 } 358 359 Color colorFromPremultipliedARGB(unsigned pixelColor) 360 { 361 RGBA32 rgba; 362 363 if (unsigned alpha = (pixelColor & 0xFF000000) >> 24) { 364 rgba = makeRGBA(((pixelColor & 0x00FF0000) >> 16) * 255 / alpha, 365 ((pixelColor & 0x0000FF00) >> 8) * 255 / alpha, 366 (pixelColor & 0x000000FF) * 255 / alpha, 367 alpha); 368 } else 369 rgba = pixelColor; 370 371 return Color(rgba); 372 } 373 374 unsigned premultipliedARGBFromColor(const Color& color) 375 { 376 unsigned pixelColor; 377 378 if (unsigned alpha = color.alpha()) { 379 pixelColor = alpha << 24 | 380 ((color.red() * alpha + 254) / 255) << 16 | 381 ((color.green() * alpha + 254) / 255) << 8 | 382 ((color.blue() * alpha + 254) / 255); 383 } else 384 pixelColor = color.rgb(); 385 386 return pixelColor; 387 } 388 389 } // namespace WebCore 390
