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
makeRGB(int r,int g,int b)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
makeRGBA(int r,int g,int b,int a)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
colorFloatToRGBAByte(float f)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
makeRGBA32FromFloats(float r,float g,float b,float a)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
colorWithOverrideAlpha(RGBA32 color,float overrideAlpha)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
calcHue(double temp1,double temp2,double hueVal)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
makeRGBAFromHSLA(double hue,double saturation,double lightness,double alpha)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
makeRGBAFromCMYKA(float c,float m,float y,float k,float a)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
parseHexColor(const UChar * name,unsigned length,RGBA32 & rgb)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
parseHexColor(const String & name,RGBA32 & rgb)150 bool Color::parseHexColor(const String& name, RGBA32& rgb)
151 {
152 return parseHexColor(name.characters(), name.length(), rgb);
153 }
154
differenceSquared(const Color & c1,const Color & c2)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
Color(const String & name)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
Color(const char * name)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
serialized() const182 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
nameForRenderTreeAsText() const219 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
findNamedColor(const String & name)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
setNamedColor(const String & name)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
light() const249 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
dark() const274 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
blendComponent(int c,int a)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
blend(const Color & source) const307 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
blendWithWhite() const323 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
getRGBA(float & r,float & g,float & b,float & a) const345 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
getRGBA(double & r,double & g,double & b,double & a) const353 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
getHSL(double & hue,double & saturation,double & lightness) const361 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
colorFromPremultipliedARGB(unsigned pixelColor)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
premultipliedARGBFromColor(const Color & color)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