blob: acd6091b64840684178112943c8c92cc714835c6 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
cr.define('tracing', function() {
/**
* Uses an embedded iframe to measure provided elements without forcing layout
* on the main document.
* @constructor
* @extends {Object}
*/
function MeasuringStick() {
var iframe = document.createElement('iframe');
iframe.style.cssText = 'width:100%;height:0;border:0;visibility:hidden';
document.body.appendChild(iframe);
this._doc = iframe.contentDocument;
this._window = iframe.contentWindow;
this._doc.body.style.cssText = 'padding:0;margin:0;overflow:hidden';
var stylesheets = document.querySelectorAll('link[rel=stylesheet]');
for (var i = 0; i < stylesheets.length; i++) {
var stylesheet = stylesheets[i];
var link = this._doc.createElement('link');
link.rel = 'stylesheet';
link.href = stylesheet.href;
this._doc.head.appendChild(link);
}
}
MeasuringStick.prototype = {
__proto__: Object.prototype,
/**
* Measures the provided element without forcing layout on the main
* document.
*/
measure: function(element) {
this._doc.body.appendChild(element);
var style = this._window.getComputedStyle(element);
var width = parseInt(style.width, 10);
var height = parseInt(style.height, 10);
this._doc.body.removeChild(element);
return { width: width, height: height };
}
};
return {
MeasuringStick: MeasuringStick
};
});