Permalink
Fetching contributors…
Cannot retrieve contributors at this time
745 lines (668 sloc) 15.9 KB
//
// color.cc
//
// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
//
#include "color.h"
#include <stdlib.h>
#include <cmath>
#include <limits>
// Compatibility with Visual Studio versions prior to VS2015
#if defined(_MSC_VER) && _MSC_VER < 1900
#define snprintf _snprintf
#endif
/*
* Parse integer value
*/
template <typename parsed_t>
static bool
parse_integer(const char** pStr, parsed_t *pParsed) {
parsed_t& c = *pParsed;
const char*& str = *pStr;
int8_t sign=1;
c = 0;
if (*str == '-') {
sign=-1;
++str;
}
else if (*str == '+')
++str;
if (*str >= '0' && *str <= '9') {
do {
c *= 10;
c += *str++ - '0';
} while (*str >= '0' && *str <= '9');
} else {
return false;
}
if (sign<0)
c=-c;
return true;
}
/*
* Parse CSS <number> value
* Adapted from http://crackprogramming.blogspot.co.il/2012/10/implement-atof.html
*/
template <typename parsed_t>
static bool
parse_css_number(const char** pStr, parsed_t *pParsed) {
parsed_t &parsed = *pParsed;
const char*& str = *pStr;
const char* startStr = str;
if (!str || !*str)
return false;
parsed_t integerPart = 0;
parsed_t fractionPart = 0;
int divisorForFraction = 1;
int sign = 1;
int exponent = 0;
int digits = 0;
bool inFraction = false;
if (*str == '-') {
++str;
sign = -1;
}
else if (*str == '+')
++str;
while (*str != '\0') {
if (*str >= '0' && *str <= '9') {
if (digits>=std::numeric_limits<parsed_t>::digits10) {
if (!inFraction)
return false;
}
else {
++digits;
if (inFraction) {
fractionPart = fractionPart*10 + (*str - '0');
divisorForFraction *= 10;
}
else {
integerPart = integerPart*10 + (*str - '0');
}
}
}
else if (*str == '.') {
if (inFraction)
break;
else
inFraction = true;
}
else if (*str == 'e') {
++str;
if (!parse_integer(&str, &exponent))
return false;
break;
}
else
break;
++str;
}
if (str != startStr) {
parsed = sign * (integerPart + fractionPart/divisorForFraction);
for (;exponent>0;--exponent)
parsed *= 10;
for (;exponent<0;++exponent)
parsed /= 10;
return true;
}
return false;
}
/*
* Clip value to the range [minValue, maxValue]
*/
template <typename T>
static T
clip(T value, T minValue, T maxValue) {
if (value > maxValue)
value = maxValue;
if (value < minValue)
value = minValue;
return value;
}
/*
* Wrap value to the range [0, limit]
*/
template <typename T>
static T
wrap_float(T value, T limit) {
return fmod(fmod(value, limit) + limit, limit);
}
/*
* Wrap value to the range [0, limit] - currently-unused integer version of wrap_float
*/
// template <typename T>
// static T wrap_int(T value, T limit) {
// return (value % limit + limit) % limit;
// }
/*
* Parse color channel value
*/
static bool
parse_rgb_channel(const char** pStr, uint8_t *pChannel) {
int channel;
if (parse_integer(pStr, &channel)) {
*pChannel = clip(channel, 0, 255);
return true;
}
return false;
}
/*
* Parse a value in degrees
*/
static bool
parse_degrees(const char** pStr, float *pDegrees) {
float degrees;
if (parse_css_number(pStr, &degrees)) {
*pDegrees = wrap_float(degrees, 360.0f);
return true;
}
return false;
}
/*
* Parse and clip a percentage value. Returns a float in the range [0, 1].
*/
static bool
parse_clipped_percentage(const char** pStr, float *pFraction) {
float percentage;
bool result = parse_css_number(pStr,&percentage);
const char*& str = *pStr;
if (result) {
if (*str == '%') {
++str;
*pFraction = clip(percentage, 0.0f, 100.0f) / 100.0f;
return result;
}
}
return false;
}
/*
* Macros to help with parsing inside rgba_from_*_string
*/
#define WHITESPACE \
while (' ' == *str) ++str;
#define WHITESPACE_OR_COMMA \
while (' ' == *str || ',' == *str) ++str;
#define CHANNEL(NAME) \
if (!parse_rgb_channel(&str, &NAME)) \
return 0; \
#define HUE(NAME) \
if (!parse_degrees(&str, &NAME)) \
return 0;
#define SATURATION(NAME) \
if (!parse_clipped_percentage(&str, &NAME)) \
return 0;
#define LIGHTNESS(NAME) SATURATION(NAME)
#define ALPHA(NAME) \
if (*str >= '1' && *str <= '9') { \
NAME = 1; \
} else { \
if ('0' == *str) ++str; \
if ('.' == *str) { \
++str; \
float n = .1f; \
while (*str >= '0' && *str <= '9') { \
NAME += (*str++ - '0') * n; \
n *= .1f; \
} \
} \
} \
do {} while (0) // require trailing semicolon
/*
* Named colors.
*/
static struct named_color {
const char *name;
uint32_t val;
} named_colors[] = {
{ "transparent", 0xFFFFFF00}
, { "aliceblue", 0xF0F8FFFF }
, { "antiquewhite", 0xFAEBD7FF }
, { "aqua", 0x00FFFFFF }
, { "aquamarine", 0x7FFFD4FF }
, { "azure", 0xF0FFFFFF }
, { "beige", 0xF5F5DCFF }
, { "bisque", 0xFFE4C4FF }
, { "black", 0x000000FF }
, { "blanchedalmond", 0xFFEBCDFF }
, { "blue", 0x0000FFFF }
, { "blueviolet", 0x8A2BE2FF }
, { "brown", 0xA52A2AFF }
, { "burlywood", 0xDEB887FF }
, { "cadetblue", 0x5F9EA0FF }
, { "chartreuse", 0x7FFF00FF }
, { "chocolate", 0xD2691EFF }
, { "coral", 0xFF7F50FF }
, { "cornflowerblue", 0x6495EDFF }
, { "cornsilk", 0xFFF8DCFF }
, { "crimson", 0xDC143CFF }
, { "cyan", 0x00FFFFFF }
, { "darkblue", 0x00008BFF }
, { "darkcyan", 0x008B8BFF }
, { "darkgoldenrod", 0xB8860BFF }
, { "darkgray", 0xA9A9A9FF }
, { "darkgreen", 0x006400FF }
, { "darkgrey", 0xA9A9A9FF }
, { "darkkhaki", 0xBDB76BFF }
, { "darkmagenta", 0x8B008BFF }
, { "darkolivegreen", 0x556B2FFF }
, { "darkorange", 0xFF8C00FF }
, { "darkorchid", 0x9932CCFF }
, { "darkred", 0x8B0000FF }
, { "darksalmon", 0xE9967AFF }
, { "darkseagreen", 0x8FBC8FFF }
, { "darkslateblue", 0x483D8BFF }
, { "darkslategray", 0x2F4F4FFF }
, { "darkslategrey", 0x2F4F4FFF }
, { "darkturquoise", 0x00CED1FF }
, { "darkviolet", 0x9400D3FF }
, { "deeppink", 0xFF1493FF }
, { "deepskyblue", 0x00BFFFFF }
, { "dimgray", 0x696969FF }
, { "dimgrey", 0x696969FF }
, { "dodgerblue", 0x1E90FFFF }
, { "firebrick", 0xB22222FF }
, { "floralwhite", 0xFFFAF0FF }
, { "forestgreen", 0x228B22FF }
, { "fuchsia", 0xFF00FFFF }
, { "gainsboro", 0xDCDCDCFF }
, { "ghostwhite", 0xF8F8FFFF }
, { "gold", 0xFFD700FF }
, { "goldenrod", 0xDAA520FF }
, { "gray", 0x808080FF }
, { "green", 0x008000FF }
, { "greenyellow", 0xADFF2FFF }
, { "grey", 0x808080FF }
, { "honeydew", 0xF0FFF0FF }
, { "hotpink", 0xFF69B4FF }
, { "indianred", 0xCD5C5CFF }
, { "indigo", 0x4B0082FF }
, { "ivory", 0xFFFFF0FF }
, { "khaki", 0xF0E68CFF }
, { "lavender", 0xE6E6FAFF }
, { "lavenderblush", 0xFFF0F5FF }
, { "lawngreen", 0x7CFC00FF }
, { "lemonchiffon", 0xFFFACDFF }
, { "lightblue", 0xADD8E6FF }
, { "lightcoral", 0xF08080FF }
, { "lightcyan", 0xE0FFFFFF }
, { "lightgoldenrodyellow", 0xFAFAD2FF }
, { "lightgray", 0xD3D3D3FF }
, { "lightgreen", 0x90EE90FF }
, { "lightgrey", 0xD3D3D3FF }
, { "lightpink", 0xFFB6C1FF }
, { "lightsalmon", 0xFFA07AFF }
, { "lightseagreen", 0x20B2AAFF }
, { "lightskyblue", 0x87CEFAFF }
, { "lightslategray", 0x778899FF }
, { "lightslategrey", 0x778899FF }
, { "lightsteelblue", 0xB0C4DEFF }
, { "lightyellow", 0xFFFFE0FF }
, { "lime", 0x00FF00FF }
, { "limegreen", 0x32CD32FF }
, { "linen", 0xFAF0E6FF }
, { "magenta", 0xFF00FFFF }
, { "maroon", 0x800000FF }
, { "mediumaquamarine", 0x66CDAAFF }
, { "mediumblue", 0x0000CDFF }
, { "mediumorchid", 0xBA55D3FF }
, { "mediumpurple", 0x9370DBFF }
, { "mediumseagreen", 0x3CB371FF }
, { "mediumslateblue", 0x7B68EEFF }
, { "mediumspringgreen", 0x00FA9AFF }
, { "mediumturquoise", 0x48D1CCFF }
, { "mediumvioletred", 0xC71585FF }
, { "midnightblue", 0x191970FF }
, { "mintcream", 0xF5FFFAFF }
, { "mistyrose", 0xFFE4E1FF }
, { "moccasin", 0xFFE4B5FF }
, { "navajowhite", 0xFFDEADFF }
, { "navy", 0x000080FF }
, { "oldlace", 0xFDF5E6FF }
, { "olive", 0x808000FF }
, { "olivedrab", 0x6B8E23FF }
, { "orange", 0xFFA500FF }
, { "orangered", 0xFF4500FF }
, { "orchid", 0xDA70D6FF }
, { "palegoldenrod", 0xEEE8AAFF }
, { "palegreen", 0x98FB98FF }
, { "paleturquoise", 0xAFEEEEFF }
, { "palevioletred", 0xDB7093FF }
, { "papayawhip", 0xFFEFD5FF }
, { "peachpuff", 0xFFDAB9FF }
, { "peru", 0xCD853FFF }
, { "pink", 0xFFC0CBFF }
, { "plum", 0xDDA0DDFF }
, { "powderblue", 0xB0E0E6FF }
, { "purple", 0x800080FF }
, { "rebeccapurple", 0x663399FF } // Source: CSS Color Level 4 draft
, { "red", 0xFF0000FF }
, { "rosybrown", 0xBC8F8FFF }
, { "royalblue", 0x4169E1FF }
, { "saddlebrown", 0x8B4513FF }
, { "salmon", 0xFA8072FF }
, { "sandybrown", 0xF4A460FF }
, { "seagreen", 0x2E8B57FF }
, { "seashell", 0xFFF5EEFF }
, { "sienna", 0xA0522DFF }
, { "silver", 0xC0C0C0FF }
, { "skyblue", 0x87CEEBFF }
, { "slateblue", 0x6A5ACDFF }
, { "slategray", 0x708090FF }
, { "slategrey", 0x708090FF }
, { "snow", 0xFFFAFAFF }
, { "springgreen", 0x00FF7FFF }
, { "steelblue", 0x4682B4FF }
, { "tan", 0xD2B48CFF }
, { "teal", 0x008080FF }
, { "thistle", 0xD8BFD8FF }
, { "tomato", 0xFF6347FF }
, { "turquoise", 0x40E0D0FF }
, { "violet", 0xEE82EEFF }
, { "wheat", 0xF5DEB3FF }
, { "white", 0xFFFFFFFF }
, { "whitesmoke", 0xF5F5F5FF }
, { "yellow", 0xFFFF00FF }
, { "yellowgreen", 0x9ACD32FF }
, { NULL, 0 }
};
/*
* Hex digit int val.
*/
static int
h(char c) {
switch (c) {
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
return c - '0';
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
return (c - 'a') + 10;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
return (c - 'A') + 10;
}
return 0;
}
/*
* Return rgba_t from rgba.
*/
rgba_t
rgba_create(uint32_t rgba) {
rgba_t color;
color.r = (double) (rgba >> 24) / 255;
color.g = (double) (rgba >> 16 & 0xff) / 255;
color.b = (double) (rgba >> 8 & 0xff) / 255;
color.a = (double) (rgba & 0xff) / 255;
return color;
}
/*
* Return a string representation of the color.
*/
void
rgba_to_string(rgba_t rgba, char *buf, size_t len) {
if (1 == rgba.a) {
snprintf(buf, len, "#%.2x%.2x%.2x"
, (int) (rgba.r * 255)
, (int) (rgba.g * 255)
, (int) (rgba.b * 255));
} else {
snprintf(buf, len, "rgba(%d, %d, %d, %.2f)"
, (int) (rgba.r * 255)
, (int) (rgba.g * 255)
, (int) (rgba.b * 255)
, rgba.a);
}
}
/*
* Return rgba from (r,g,b,a).
*/
static inline int32_t
rgba_from_rgba(uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
return
r << 24
| g << 16
| b << 8
| a;
}
/*
* Helper function used in rgba_from_hsla().
* Based on http://dev.w3.org/csswg/css-color-4/#hsl-to-rgb
*/
static float
hue_to_rgb(float t1, float t2, float hue) {
if (hue < 0)
hue += 6;
if (hue >= 6)
hue -= 6;
if (hue < 1)
return (t2 - t1) * hue + t1;
else if (hue < 3)
return t2;
else if (hue < 4)
return (t2 - t1) * (4 - hue) + t1;
else
return t1;
}
/*
* Return rgba from (h,s,l,a).
* Expects h values in the range [0, 360), and s, l, a in the range [0, 1].
* Adapted from http://dev.w3.org/csswg/css-color-4/#hsl-to-rgb
*/
static inline int32_t
rgba_from_hsla(float h_deg, float s, float l, float a) {
uint8_t r, g, b;
float h = (6 * h_deg) / 360.0f, m1, m2;
if (l<=0.5)
m2=l*(s+1);
else
m2=l+s-l*s;
m1 = l*2 - m2;
// Scale and round the RGB components
r = (uint8_t)floor(hue_to_rgb(m1, m2, h + 2) * 255 + 0.5);
g = (uint8_t)floor(hue_to_rgb(m1, m2, h ) * 255 + 0.5);
b = (uint8_t)floor(hue_to_rgb(m1, m2, h - 2) * 255 + 0.5);
return rgba_from_rgba(r, g, b, (uint8_t) (a * 255));
}
/*
* Return rgba from (h,s,l).
* Expects h values in the range [0, 360), and s, l in the range [0, 1].
*/
static inline int32_t
rgba_from_hsl(float h_deg, float s, float l) {
return rgba_from_hsla(h_deg, s, l, 1.0);
}
/*
* Return rgba from (r,g,b).
*/
static int32_t
rgba_from_rgb(uint8_t r, uint8_t g, uint8_t b) {
return rgba_from_rgba(r, g, b, 255);
}
/*
* Return rgb from "#RRGGBB".
*/
static int32_t
rgba_from_hex6_string(const char *str) {
return rgba_from_rgb(
(h(str[0]) << 4) + h(str[1])
, (h(str[2]) << 4) + h(str[3])
, (h(str[4]) << 4) + h(str[5])
);
}
/*
* Return rgb from "#RGB"
*/
static int32_t
rgba_from_hex3_string(const char *str) {
return rgba_from_rgb(
(h(str[0]) << 4) + h(str[0])
, (h(str[1]) << 4) + h(str[1])
, (h(str[2]) << 4) + h(str[2])
);
}
/*
* Return rgb from "rgb()"
*/
static int32_t
rgba_from_rgb_string(const char *str, short *ok) {
if (str == strstr(str, "rgb(")) {
str += 4;
WHITESPACE;
uint8_t r = 0, g = 0, b = 0;
CHANNEL(r);
WHITESPACE_OR_COMMA;
CHANNEL(g);
WHITESPACE_OR_COMMA;
CHANNEL(b);
WHITESPACE;
return *ok = 1, rgba_from_rgb(r, g, b);
}
return *ok = 0;
}
/*
* Return rgb from "rgba()"
*/
static int32_t
rgba_from_rgba_string(const char *str, short *ok) {
if (str == strstr(str, "rgba(")) {
str += 5;
WHITESPACE;
uint8_t r = 0, g = 0, b = 0;
float a = 0;
CHANNEL(r);
WHITESPACE_OR_COMMA;
CHANNEL(g);
WHITESPACE_OR_COMMA;
CHANNEL(b);
WHITESPACE_OR_COMMA;
ALPHA(a);
WHITESPACE;
return *ok = 1, rgba_from_rgba(r, g, b, (int) (a * 255));
}
return *ok = 0;
}
/*
* Return rgb from "hsla()"
*/
static int32_t
rgba_from_hsla_string(const char *str, short *ok) {
if (str == strstr(str, "hsla(")) {
str += 5;
WHITESPACE;
float h_deg = 0;
float s = 0, l = 0;
float a = 0;
HUE(h_deg);
WHITESPACE_OR_COMMA;
SATURATION(s);
WHITESPACE_OR_COMMA;
LIGHTNESS(l);
WHITESPACE_OR_COMMA;
ALPHA(a);
WHITESPACE;
return *ok = 1, rgba_from_hsla(h_deg, s, l, a);
}
return *ok = 0;
}
/*
* Return rgb from "hsl()"
*/
static int32_t
rgba_from_hsl_string(const char *str, short *ok) {
if (str == strstr(str, "hsl(")) {
str += 4;
WHITESPACE;
float h_deg = 0;
float s = 0, l = 0;
HUE(h_deg);
WHITESPACE_OR_COMMA;
SATURATION(s);
WHITESPACE_OR_COMMA;
LIGHTNESS(l);
WHITESPACE;
return *ok = 1, rgba_from_hsl(h_deg, s, l);
}
return *ok = 0;
}
/*
* Return rgb from:
*
* - "#RGB"
* - "#RRGGBB"
*
*/
static int32_t
rgba_from_hex_string(const char *str, short *ok) {
size_t len = strlen(str);
*ok = 1;
if (6 == len) return rgba_from_hex6_string(str);
if (3 == len) return rgba_from_hex3_string(str);
return *ok = 0;
}
/*
* Return named color value.
*/
static int32_t
rgba_from_name_string(const char *str, short *ok) {
int i = 0;
struct named_color color;
while ((color = named_colors[i++]).name) {
if (*str == *color.name && 0 == strcmp(str, color.name))
return *ok = 1, color.val;
}
return *ok = 0;
}
/*
* Return rgb from:
*
* - #RGB
* - #RRGGBB
* - rgb(r,g,b)
* - rgba(r,g,b,a)
* - hsl(h,s,l)
* - hsla(h,s,l,a)
* - name
*
*/
int32_t
rgba_from_string(const char *str, short *ok) {
if ('#' == str[0])
return rgba_from_hex_string(++str, ok);
if (str == strstr(str, "rgba"))
return rgba_from_rgba_string(str, ok);
if (str == strstr(str, "rgb"))
return rgba_from_rgb_string(str, ok);
if (str == strstr(str, "hsla"))
return rgba_from_hsla_string(str, ok);
if (str == strstr(str, "hsl"))
return rgba_from_hsl_string(str, ok);
return rgba_from_name_string(str, ok);
}
/*
* Inspect the given rgba color.
*/
void
rgba_inspect(int32_t rgba) {
printf("rgba(%d,%d,%d,%d)\n"
, rgba >> 24 & 0xff
, rgba >> 16 & 0xff
, rgba >> 8 & 0xff
, rgba & 0xff
);
}