openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
202 lines (175 loc) • 4.75 kB
JavaScript
goog.provide('ol.color');
goog.require('ol.asserts');
goog.require('ol.math');
/**
* This RegExp matches # followed by 3 or 6 hex digits.
* @const
* @type {RegExp}
* @private
*/
ol.color.HEX_COLOR_RE_ = /^#(?:[0-9a-f]{3}){1,2}$/i;
/**
* Regular expression for matching potential named color style strings.
* @const
* @type {RegExp}
* @private
*/
ol.color.NAMED_COLOR_RE_ = /^([a-z]*)$/i;
/**
* Return the color as an array. This function maintains a cache of calculated
* arrays which means the result should not be modified.
* @param {ol.Color|string} color Color.
* @return {ol.Color} Color.
* @api
*/
ol.color.asArray = function(color) {
if (Array.isArray(color)) {
return color;
} else {
return ol.color.fromString(/** @type {string} */ (color));
}
};
/**
* Return the color as an rgba string.
* @param {ol.Color|string} color Color.
* @return {string} Rgba string.
* @api
*/
ol.color.asString = function(color) {
if (typeof color === 'string') {
return color;
} else {
return ol.color.toString(color);
}
};
/**
* Return named color as an rgba string.
* @param {string} color Named color.
* @return {string} Rgb string.
*/
ol.color.fromNamed = function(color) {
var el = document.createElement('div');
el.style.color = color;
document.body.appendChild(el);
var rgb = getComputedStyle(el).color;
document.body.removeChild(el);
return rgb;
};
/**
* @param {string} s String.
* @return {ol.Color} Color.
*/
ol.color.fromString = (
function() {
// We maintain a small cache of parsed strings. To provide cheap LRU-like
// semantics, whenever the cache grows too large we simply delete an
// arbitrary 25% of the entries.
/**
* @const
* @type {number}
*/
var MAX_CACHE_SIZE = 1024;
/**
* @type {Object.<string, ol.Color>}
*/
var cache = {};
/**
* @type {number}
*/
var cacheSize = 0;
return (
/**
* @param {string} s String.
* @return {ol.Color} Color.
*/
function(s) {
var color;
if (cache.hasOwnProperty(s)) {
color = cache[s];
} else {
if (cacheSize >= MAX_CACHE_SIZE) {
var i = 0;
var key;
for (key in cache) {
if ((i++ & 3) === 0) {
delete cache[key];
--cacheSize;
}
}
}
color = ol.color.fromStringInternal_(s);
cache[s] = color;
++cacheSize;
}
return color;
});
})();
/**
* @param {string} s String.
* @private
* @return {ol.Color} Color.
*/
ol.color.fromStringInternal_ = function(s) {
var r, g, b, a, color, parts;
if (ol.color.NAMED_COLOR_RE_.exec(s)) {
s = ol.color.fromNamed(s);
}
if (ol.color.HEX_COLOR_RE_.exec(s)) { // hex
var n = s.length - 1; // number of hex digits
ol.asserts.assert(n == 3 || n == 6, 54); // Hex color should have 3 or 6 digits
var d = n == 3 ? 1 : 2; // number of digits per channel
r = parseInt(s.substr(1 + 0 * d, d), 16);
g = parseInt(s.substr(1 + 1 * d, d), 16);
b = parseInt(s.substr(1 + 2 * d, d), 16);
if (d == 1) {
r = (r << 4) + r;
g = (g << 4) + g;
b = (b << 4) + b;
}
a = 1;
color = [r, g, b, a];
} else if (s.indexOf('rgba(') == 0) { // rgba()
parts = s.slice(5, -1).split(',').map(Number);
color = ol.color.normalize(parts);
} else if (s.indexOf('rgb(') == 0) { // rgb()
parts = s.slice(4, -1).split(',').map(Number);
parts.push(1);
color = ol.color.normalize(parts);
} else {
ol.asserts.assert(false, 14); // Invalid color
}
return /** @type {ol.Color} */ (color);
};
/**
* @param {ol.Color} color Color.
* @param {ol.Color=} opt_color Color.
* @return {ol.Color} Clamped color.
*/
ol.color.normalize = function(color, opt_color) {
var result = opt_color || [];
result[0] = ol.math.clamp((color[0] + 0.5) | 0, 0, 255);
result[1] = ol.math.clamp((color[1] + 0.5) | 0, 0, 255);
result[2] = ol.math.clamp((color[2] + 0.5) | 0, 0, 255);
result[3] = ol.math.clamp(color[3], 0, 1);
return result;
};
/**
* @param {ol.Color} color Color.
* @return {string} String.
*/
ol.color.toString = function(color) {
var r = color[0];
if (r != (r | 0)) {
r = (r + 0.5) | 0;
}
var g = color[1];
if (g != (g | 0)) {
g = (g + 0.5) | 0;
}
var b = color[2];
if (b != (b | 0)) {
b = (b + 0.5) | 0;
}
var a = color[3] === undefined ? 1 : color[3];
return 'rgba(' + r + ',' + g + ',' + b + ',' + a + ')';
};