55 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			55 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.FontMetrics = void 0;
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var util_1 = require("../core/util");
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var SAMPLE_TEXT = 'Hidden Text';
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var FontMetrics = /** @class */ (function () {
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    function FontMetrics(document) {
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        this._data = {};
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        this._document = document;
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    }
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    FontMetrics.prototype.parseMetrics = function (fontFamily, fontSize) {
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        var container = this._document.createElement('div');
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        var img = this._document.createElement('img');
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        var span = this._document.createElement('span');
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        var body = this._document.body;
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        container.style.visibility = 'hidden';
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        container.style.fontFamily = fontFamily;
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        container.style.fontSize = fontSize;
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        container.style.margin = '0';
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        container.style.padding = '0';
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        container.style.whiteSpace = 'nowrap';
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        body.appendChild(container);
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        img.src = util_1.SMALL_IMAGE;
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        img.width = 1;
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        img.height = 1;
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        img.style.margin = '0';
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        img.style.padding = '0';
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        img.style.verticalAlign = 'baseline';
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        span.style.fontFamily = fontFamily;
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        span.style.fontSize = fontSize;
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        span.style.margin = '0';
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        span.style.padding = '0';
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        span.appendChild(this._document.createTextNode(SAMPLE_TEXT));
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        container.appendChild(span);
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        container.appendChild(img);
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        var baseline = img.offsetTop - span.offsetTop + 2;
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        container.removeChild(span);
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        container.appendChild(this._document.createTextNode(SAMPLE_TEXT));
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        container.style.lineHeight = 'normal';
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        img.style.verticalAlign = 'super';
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        var middle = img.offsetTop - container.offsetTop + 2;
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        body.removeChild(container);
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        return { baseline: baseline, middle: middle };
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    };
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    FontMetrics.prototype.getMetrics = function (fontFamily, fontSize) {
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        var key = fontFamily + " " + fontSize;
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        if (typeof this._data[key] === 'undefined') {
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            this._data[key] = this.parseMetrics(fontFamily, fontSize);
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        }
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        return this._data[key];
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    };
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    return FontMetrics;
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}());
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exports.FontMetrics = FontMetrics;
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//# sourceMappingURL=font-metrics.js.map
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