detect-font
Version:
Detect which font your system has cherry-picked from font-family.
215 lines (169 loc) • 6.42 kB
JavaScript
module.exports =
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/* 0 */
/***/ function(module, exports, __webpack_require__) {
module.exports = __webpack_require__(1);
/***/ },
/* 1 */
/***/ function(module, exports, __webpack_require__) {
'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.supportedFonts = exports.detectFont = exports.removeQuotes = undefined;
var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
var _isElement = __webpack_require__(2);
var _isElement2 = _interopRequireDefault(_isElement);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
* @constant DEFAULT_OPTIONS
* @type {Object}
*/
var DEFAULT_OPTIONS = {
text: 'abcdefghijklmnopqrstuvwxyz0123456789',
fontSize: 72,
baseFont: 'monospace'
};
/**
* @constant BASE_FONTS
* @type {String[]}
*/
var BASE_FONTS = ['sans-serif', 'serif', 'monospace'];
/**
* @method removeQuotes
* @param {String} name
* @return {String}
*/
var removeQuotes = exports.removeQuotes = function removeQuotes(name) {
var matches = String(name).match(/^["']?(.+?)["']?$/i);
return Array.isArray(matches) ? matches[1] : '';
};
/**
* @method throwException
* @param {String} message
* @return {void}
* @throw {Error}
*/
var throwException = function throwException(message) {
throw new Error('DetectFont: ' + message + '.');
};
/**
* @method assertText
* @param {String} text
* @return {void}
* @throw {Error}
*/
var assertText = function assertText(text) {
text === '' && throwException('Setting text to an empty string will always yield false positives');
};
/**
* @method assertFontSize
* @param {Number} fontSize
* @return {void}
* @throw {Error}
*/
var assertFontSize = function assertFontSize(fontSize) {
fontSize === 0 && throwException('Setting font size to zero will always yield false positives');
};
/**
* @method detectFont
* @param {HTMLElement} element
* @param {Object} [options = DEFAULT_OPTIONS]
* @return {String|Boolean}
* @throw {Error}
*/
var detectFont = exports.detectFont = function detectFont(element) {
var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : DEFAULT_OPTIONS;
if (!(0, _isElement2.default)(element)) {
return void throwException('Cannot detect font on a non-element');
}
return supportedFonts(element, options)[0] || false;
};
/**
* @method supportedFonts
* @param {HTMLElement} element
* @param {Object} [options = DEFAULT_OPTIONS]
* @return {Array}
*/
var supportedFonts = exports.supportedFonts = function supportedFonts(element) {
var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : DEFAULT_OPTIONS;
if (!(0, _isElement2.default)(element)) {
return [];
}
var opts = _extends({}, DEFAULT_OPTIONS, options);
assertText(options.text);
assertFontSize(options.fontSize);
var properties = window.getComputedStyle(element);
var fontFamily = properties.getPropertyValue('font-family') || element.style.fontFamily || 'serif';
var fonts = fontFamily.split(',');
var canvas = window.document.createElement('canvas');
var context = canvas.getContext('2d');
return fonts.map(function (font) {
return font.trim();
}).map(removeQuotes).map(function (fontName) {
if (!!~BASE_FONTS.indexOf(fontName.toLowerCase())) {
return fontName;
}
context.font = opts.fontSize + 'px ' + options.baseFont;
var baselineSize = context.measureText(opts.text).width;
context.font = opts.fontSize + 'px ' + fontName + ', ' + options.baseFont;
return baselineSize !== context.measureText(opts.text).width ? fontName : false;
}).filter(function (value) {
return value !== false;
});
};
/***/ },
/* 2 */
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'use strict';
var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };
(function (root) {
function isElement(value) {
return value && value.nodeType === 1 && value && (typeof value === 'undefined' ? 'undefined' : _typeof(value)) == 'object' && Object.prototype.toString.call(value).indexOf('Element') > -1;
}
if (true) {
if (typeof module !== 'undefined' && module.exports) {
exports = module.exports = isElement;
}
exports.isElement = isElement;
} else if (typeof define === 'function' && define.amd) {
define([], function () {
return isElement;
});
} else {
root.isElement = isElement;
}
})(undefined);
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