accessibility-developer-tools
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This is a library of accessibility-related testing and utility code.
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JavaScript
// Copyright 2007 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// All Rights Reserved.
/**
* @fileoverview Provides utility routines for copying modified
* {@code CSSRule} objects from the parent document into iframes so that any
* content in the iframe will be styled as if it was inline in the parent
* document.
*
* <p>
* For example, you might have this CSS rule:
*
* #content .highlighted { background-color: yellow; }
*
* And this DOM structure:
*
* <div id="content">
* <iframe />
* </div>
*
* Then inside the iframe you have:
*
* <body>
* <div class="highlighted">
* </body>
*
* If you copied the CSS rule directly into the iframe, it wouldn't match the
* .highlighted div. So we rewrite the original stylesheets based on the
* context where the iframe is going to be inserted. In this case the CSS
* selector would be rewritten to:
*
* body .highlighted { background-color: yellow; }
* </p>
*
*/
goog.provide('goog.cssom.iframe.style');
goog.require('goog.asserts');
goog.require('goog.cssom');
goog.require('goog.dom');
goog.require('goog.dom.NodeType');
goog.require('goog.dom.TagName');
goog.require('goog.dom.classlist');
goog.require('goog.string');
goog.require('goog.style');
goog.require('goog.userAgent');
/**
* Regexp that matches "a", "a:link", "a:visited", etc.
* @type {RegExp}
* @private
*/
goog.cssom.iframe.style.selectorPartAnchorRegex_ =
/a(:(link|visited|active|hover))?/;
/**
* Delimiter between selectors (h1, h2)
* @type {string}
* @private
*/
goog.cssom.iframe.style.SELECTOR_DELIMITER_ = ',';
/**
* Delimiter between selector parts (.main h1)
* @type {string}
* @private
*/
goog.cssom.iframe.style.SELECTOR_PART_DELIMITER_ = ' ';
/**
* Delimiter marking the start of a css rules section ( h1 { )
* @type {string}
* @private
*/
goog.cssom.iframe.style.DECLARATION_START_DELIMITER_ = '{';
/**
* Delimiter marking the end of a css rules section ( } )
* @type {string}
* @private
*/
goog.cssom.iframe.style.DECLARATION_END_DELIMITER_ = '}\n';
/**
* Class representing a CSS rule set. A rule set is something like this:
* h1, h2 { font-family: Arial; color: red; }
* @constructor
* @private
*/
goog.cssom.iframe.style.CssRuleSet_ = function() {
/**
* Text of the declarations inside the rule set.
* For example: 'font-family: Arial; color: red;'
* @type {string}
*/
this.declarationText = '';
/**
* Array of CssSelector objects, one for each selector.
* Example: [h1, h2]
* @type {Array<goog.cssom.iframe.style.CssSelector_>}
*/
this.selectors = [];
};
/**
* Initializes the rule set from a {@code CSSRule}.
*
* @param {CSSRule} cssRule The {@code CSSRule} to initialize from.
* @return {boolean} True if initialization succeeded. We only support
* {@code CSSStyleRule} and {@code CSSFontFaceRule} objects.
*/
goog.cssom.iframe.style.CssRuleSet_.prototype.initializeFromCssRule = function(
cssRule) {
var ruleStyle = cssRule.style; // Cache object for performance.
if (!ruleStyle) {
return false;
}
var selector;
var declarations = '';
if (ruleStyle && (selector = cssRule.selectorText) &&
(declarations = ruleStyle.cssText)) {
// IE get confused about cssText context if a stylesheet uses the
// mid-pass hack, and it ends up with an open comment (/*) but no
// closing comment. This will effectively comment out large parts
// of generated stylesheets later. This errs on the safe side by
// always tacking on an empty comment to force comments to be closed
// We used to check for a troublesome open comment using a regular
// expression, but it's faster not to check and always do this.
if (goog.userAgent.IE) {
declarations += '/* */';
}
} else if (cssRule.cssText) {
var cssSelectorMatch = /([^\{]+)\{/;
var endTagMatch = /\}[^\}]*$/g;
// cssRule.cssText contains both selector and declarations:
// parse them out.
selector = cssSelectorMatch.exec(cssRule.cssText)[1];
// Remove selector, {, and trailing }.
declarations =
cssRule.cssText.replace(cssSelectorMatch, '').replace(endTagMatch, '');
}
if (selector) {
this.setSelectorsFromString(selector);
this.declarationText = declarations;
return true;
}
return false;
};
/**
* Parses a selectors string (which may contain multiple comma-delimited
* selectors) and loads the results into this.selectors.
* @param {string} selectorsString String containing selectors.
*/
goog.cssom.iframe.style.CssRuleSet_.prototype.setSelectorsFromString = function(
selectorsString) {
this.selectors = [];
var selectors = selectorsString.split(/,\s*/gm);
for (var i = 0; i < selectors.length; i++) {
var selector = selectors[i];
if (selector.length > 0) {
this.selectors.push(new goog.cssom.iframe.style.CssSelector_(selector));
}
}
};
/**
* Make a copy of this ruleset.
* @return {!goog.cssom.iframe.style.CssRuleSet_} A new CssRuleSet containing
* the same data as this one.
*/
goog.cssom.iframe.style.CssRuleSet_.prototype.clone = function() {
var newRuleSet = new goog.cssom.iframe.style.CssRuleSet_();
newRuleSet.selectors = this.selectors.concat();
newRuleSet.declarationText = this.declarationText;
return newRuleSet;
};
/**
* Set the declaration text with properties from a given object.
* @param {Object} sourceObject Object whose properties and values should
* be used to generate the declaration text.
* @param {boolean=} opt_important Whether !important should be added to each
* declaration.
*/
goog.cssom.iframe.style.CssRuleSet_.prototype.setDeclarationTextFromObject =
function(sourceObject, opt_important) {
var stringParts = [];
// TODO(user): for ... in is costly in IE6 (extra garbage collection).
for (var prop in sourceObject) {
var value = sourceObject[prop];
if (value) {
stringParts.push(
prop, ':', value, (opt_important ? ' !important' : ''), ';');
}
}
this.declarationText = stringParts.join('');
};
/**
* Serializes this CssRuleSet_ into an array as a series of strings.
* The array can then be join()-ed to get a string representation
* of this ruleset.
* @param {Array<string>} array The array to which to append strings.
*/
goog.cssom.iframe.style.CssRuleSet_.prototype.writeToArray = function(array) {
var selectorCount = this.selectors.length;
var matchesAnchorTag = false;
for (var i = 0; i < selectorCount; i++) {
var selectorParts = this.selectors[i].parts;
var partCount = selectorParts.length;
for (var j = 0; j < partCount; j++) {
array.push(
selectorParts[j].inputString_,
goog.cssom.iframe.style.SELECTOR_PART_DELIMITER_);
}
if (i < (selectorCount - 1)) {
array.push(goog.cssom.iframe.style.SELECTOR_DELIMITER_);
}
if (goog.userAgent.GECKO && !goog.userAgent.isVersionOrHigher('1.9a')) {
// In Gecko pre-1.9 (Firefox 2 and lower) we need to add !important
// to rulesets that match "A" tags, otherwise Gecko's built-in
// stylesheet will take precedence when designMode is on.
matchesAnchorTag = matchesAnchorTag ||
goog.cssom.iframe.style.selectorPartAnchorRegex_.test(
selectorParts[partCount - 1].inputString_);
}
}
var declarationText = this.declarationText;
if (matchesAnchorTag) {
declarationText =
goog.cssom.iframe.style.makeColorRuleImportant_(declarationText);
}
array.push(
goog.cssom.iframe.style.DECLARATION_START_DELIMITER_, declarationText,
goog.cssom.iframe.style.DECLARATION_END_DELIMITER_);
};
/**
* Regexp that matches "color: value;".
* @type {RegExp}
* @private
*/
goog.cssom.iframe.style.colorImportantReplaceRegex_ =
/(^|;|{)\s*color:([^;]+);/g;
/**
* Adds !important to a css color: rule
* @param {string} cssText Text of the CSS rule(s) to modify.
* @return {string} Text with !important added to the color: rule if found.
* @private
*/
goog.cssom.iframe.style.makeColorRuleImportant_ = function(cssText) {
// Replace to insert a "! important" string.
return cssText.replace(
goog.cssom.iframe.style.colorImportantReplaceRegex_,
'$1 color: $2 ! important; ');
};
/**
* Represents a single CSS selector, as described in
* http://www.w3.org/TR/REC-CSS2/selector.html
* Currently UNSUPPORTED are the following selector features:
* <ul>
* <li>pseudo-classes (:hover)
* <li>child selectors (div > h1)
* <li>adjacent sibling selectors (div + h1)
* <li>attribute selectors (input[type=submit])
* </ul>
* @param {string=} opt_selectorString String containing selectors to parse.
* @constructor
* @private
*/
goog.cssom.iframe.style.CssSelector_ = function(opt_selectorString) {
/**
* Object to track ancestry matches to speed up repeatedly testing this
* CssSelector against the same NodeAncestry object.
* @type {Object}
* @private
*/
this.ancestryMatchCache_ = {};
if (opt_selectorString) {
this.setPartsFromString_(opt_selectorString);
}
};
/**
* Parses a selector string into individual parts.
* @param {string} selectorString A string containing a CSS selector.
* @private
*/
goog.cssom.iframe.style.CssSelector_.prototype.setPartsFromString_ = function(
selectorString) {
var parts = [];
var selectorPartStrings = selectorString.split(/\s+/gm);
for (var i = 0; i < selectorPartStrings.length; i++) {
if (!selectorPartStrings[i]) {
continue; // Skip empty strings.
}
var part =
new goog.cssom.iframe.style.CssSelectorPart_(selectorPartStrings[i]);
parts.push(part);
}
this.parts = parts;
};
/**
* Tests to see what part of a DOM element hierarchy would be matched by
* this selector, and returns the indexes of the matching element and matching
* selector part.
* <p>
* For example, given this hierarchy:
* document > html > body > div.content > div.sidebar > p
* and this CSS selector:
* body div.sidebar h1
* This would return {elementIndex: 4, selectorPartIndex: 1},
* indicating that the element at index 4 matched
* the css selector at index 1.
* </p>
* @param {goog.cssom.iframe.style.NodeAncestry_} elementAncestry Object
* representing an element and its ancestors.
* @return {Object} Object with the properties elementIndex and
* selectorPartIndex, or null if there was no match.
*/
goog.cssom.iframe.style.CssSelector_.prototype.matchElementAncestry = function(
elementAncestry) {
var ancestryUid = elementAncestry.uid;
if (this.ancestryMatchCache_[ancestryUid]) {
return this.ancestryMatchCache_[ancestryUid];
}
// Walk through the selector parts and see how far down the element hierarchy
// we can go while matching the selector parts.
var elementIndex = 0;
var match = null;
var selectorPart = null;
var lastSelectorPart = null;
var ancestorNodes = elementAncestry.nodes;
var ancestorNodeCount = ancestorNodes.length;
for (var i = 0; i <= this.parts.length; i++) {
selectorPart = this.parts[i];
while (elementIndex < ancestorNodeCount) {
var currentElementInfo = ancestorNodes[elementIndex];
if (selectorPart && selectorPart.testElement(currentElementInfo)) {
match = {elementIndex: elementIndex, selectorPartIndex: i};
elementIndex++;
break;
} else if (
lastSelectorPart &&
lastSelectorPart.testElement(currentElementInfo)) {
match = {elementIndex: elementIndex, selectorPartIndex: i - 1};
}
elementIndex++;
}
lastSelectorPart = selectorPart;
}
this.ancestryMatchCache_[ancestryUid] = match;
return match;
};
/**
* Represents one part of a CSS Selector. For example in the selector
* 'body #foo .bar', body, #foo, and .bar would be considered selector parts.
* In the official CSS spec these are called "simple selectors".
* @param {string} selectorPartString A string containing the selector part
* in css format.
* @constructor
* @private
*/
goog.cssom.iframe.style.CssSelectorPart_ = function(selectorPartString) {
// Only one CssSelectorPart instance should exist for a given string.
var cacheEntry =
goog.cssom.iframe.style.CssSelectorPart_.instances_[selectorPartString];
if (cacheEntry) {
return cacheEntry;
}
// Optimization to avoid the more-expensive lookahead.
var identifiers;
if (selectorPartString.match(/[#\.]/)) {
// Lookahead regexp, won't work on IE 5.0.
identifiers = selectorPartString.split(/(?=[#\.])/);
} else {
identifiers = [selectorPartString];
}
var properties = {};
for (var i = 0; i < identifiers.length; i++) {
var identifier = identifiers[i];
if (identifier.charAt(0) == '.') {
properties.className = identifier.substring(1, identifier.length);
} else if (identifier.charAt(0) == '#') {
properties.id = identifier.substring(1, identifier.length);
} else {
properties.tagName = identifier.toUpperCase();
}
}
this.inputString_ = selectorPartString;
this.matchProperties_ = properties;
this.testedElements_ = {};
goog.cssom.iframe.style.CssSelectorPart_.instances_[selectorPartString] =
this;
};
/**
* Cache of existing CssSelectorPart_ instances.
* @type {Object}
* @private
*/
goog.cssom.iframe.style.CssSelectorPart_.instances_ = {};
/**
* Test whether an element matches this selector part, considered in isolation.
* @param {Object} elementInfo Element properties to test.
* @return {boolean} Whether the element matched.
*/
goog.cssom.iframe.style.CssSelectorPart_.prototype.testElement = function(
elementInfo) {
var elementUid = elementInfo.uid;
var cachedMatch = this.testedElements_[elementUid];
if (typeof cachedMatch != 'undefined') {
return cachedMatch;
}
var matchProperties = this.matchProperties_;
var testTag = matchProperties.tagName;
var testClass = matchProperties.className;
var testId = matchProperties.id;
var matched = true;
if (testTag && testTag != '*' && testTag != elementInfo.nodeName) {
matched = false;
} else if (testId && testId != elementInfo.id) {
matched = false;
} else if (testClass && !elementInfo.classNames[testClass]) {
matched = false;
}
this.testedElements_[elementUid] = matched;
return matched;
};
/**
* Represents an element and all its parent/ancestor nodes.
* This class exists as an optimization so we run tests on an element
* hierarchy multiple times without walking the dom each time.
* @param {Element} el The DOM element whose ancestry should be stored.
* @constructor
* @private
*/
goog.cssom.iframe.style.NodeAncestry_ = function(el) {
var node = el;
var nodeUid = goog.getUid(node);
// Return an existing object from the cache if one exits for this node.
var ancestry = goog.cssom.iframe.style.NodeAncestry_.instances_[nodeUid];
if (ancestry) {
return ancestry;
}
var nodes = [];
do {
var nodeInfo = {id: node.id, nodeName: node.nodeName};
nodeInfo.uid = goog.getUid(nodeInfo);
var className = node.className;
var classNamesLookup = {};
if (className) {
var classNames = goog.dom.classlist.get(goog.asserts.assertElement(node));
for (var i = 0; i < classNames.length; i++) {
classNamesLookup[classNames[i]] = 1;
}
}
nodeInfo.classNames = classNamesLookup;
nodes.unshift(nodeInfo);
} while (node = node.parentNode);
/**
* Array of nodes in order of hierarchy from the top of the document
* to the node passed to the constructor
* @type {Array<Node>}
*/
this.nodes = nodes;
this.uid = goog.getUid(this);
goog.cssom.iframe.style.NodeAncestry_.instances_[nodeUid] = this;
};
/**
* Object for caching existing NodeAncestry instances.
* @private
*/
goog.cssom.iframe.style.NodeAncestry_.instances_ = {};
/**
* Throw away all cached dom information. Call this if you've modified
* the structure or class/id attributes of your document and you want
* to recalculate the currently applied CSS rules.
*/
goog.cssom.iframe.style.resetDomCache = function() {
goog.cssom.iframe.style.NodeAncestry_.instances_ = {};
};
/**
* Inspects a document and returns all active rule sets
* @param {Document} doc The document from which to read CSS rules.
* @return {!Array<goog.cssom.iframe.style.CssRuleSet_>} An array of CssRuleSet
* objects representing all the active rule sets in the document.
* @private
*/
goog.cssom.iframe.style.getRuleSetsFromDocument_ = function(doc) {
var ruleSets = [];
var styleSheets = goog.cssom.getAllCssStyleSheets(doc.styleSheets);
for (var i = 0, styleSheet; styleSheet = styleSheets[i]; i++) {
var domRuleSets = goog.cssom.getCssRulesFromStyleSheet(styleSheet);
if (domRuleSets && domRuleSets.length) {
for (var j = 0, n = domRuleSets.length; j < n; j++) {
var ruleSet = new goog.cssom.iframe.style.CssRuleSet_();
if (ruleSet.initializeFromCssRule(domRuleSets[j])) {
ruleSets.push(ruleSet);
}
}
}
}
return ruleSets;
};
/**
* Static object to cache rulesets read from documents. Inspecting all
* active css rules is an expensive operation, so its best to only do
* it once and then cache the results.
* @type {Object}
* @private
*/
goog.cssom.iframe.style.ruleSetCache_ = {};
/**
* Cache of ruleset objects keyed by document unique ID.
* @type {Object}
* @private
*/
goog.cssom.iframe.style.ruleSetCache_.ruleSetCache_ = {};
/**
* Loads ruleset definitions from a document. If the cache already
* has rulesets for this document the cached version will be replaced.
* @param {Document} doc The document from which to load rulesets.
*/
goog.cssom.iframe.style.ruleSetCache_.loadRuleSetsForDocument = function(doc) {
var docUid = goog.getUid(doc);
goog.cssom.iframe.style.ruleSetCache_.ruleSetCache_[docUid] =
goog.cssom.iframe.style.getRuleSetsFromDocument_(doc);
};
/**
* Retrieves the array of css rulesets for this document. A cached
* version will be used when possible.
* @param {Document} doc The document for which to get rulesets.
* @return {!Array<goog.cssom.iframe.style.CssRuleSet_>} An array of CssRuleSet
* objects representing the css rule sets in the supplied document.
*/
goog.cssom.iframe.style.ruleSetCache_.getRuleSetsForDocument = function(doc) {
var docUid = goog.getUid(doc);
var cache = goog.cssom.iframe.style.ruleSetCache_.ruleSetCache_;
if (!cache[docUid]) {
goog.cssom.iframe.style.ruleSetCache_.loadRuleSetsForDocument(doc);
}
// Build a cloned copy of rulesets array, so if object in the returned array
// get modified future calls will still return the original unmodified
// versions.
var ruleSets = cache[docUid];
var ruleSetsCopy = [];
for (var i = 0; i < ruleSets.length; i++) {
ruleSetsCopy.push(ruleSets[i].clone());
}
return ruleSetsCopy;
};
/**
* Array of CSS properties that are inherited by child nodes, according to
* the CSS 2.1 spec. Properties that may be set to relative values, such
* as font-size, and line-height, are omitted.
* @type {Array<string>}
* @private
*/
goog.cssom.iframe.style.inheritedProperties_ = [
'color',
'visibility',
'quotes',
'list-style-type',
'list-style-image',
'list-style-position',
'list-style',
'page-break-inside',
'orphans',
'widows',
'font-family',
'font-style',
'font-variant',
'font-weight',
'text-indent',
'text-align',
'text-transform',
'white-space',
'caption-side',
'border-collapse',
'border-spacing',
'empty-cells',
'cursor'
];
/**
* Array of CSS 2.1 properties that directly effect text nodes.
* @type {Array<string>}
* @private
*/
goog.cssom.iframe.style.textProperties_ = [
'font-family', 'font-size', 'font-weight', 'font-variant', 'font-style',
'color', 'text-align', 'text-decoration', 'text-indent', 'text-transform',
'letter-spacing', 'white-space', 'word-spacing'
];
/**
* Reads the current css rules from element's document, and returns them
* rewriting selectors so that any rules that formerly applied to element will
* be applied to doc.body. This makes it possible to replace a block in a page
* with an iframe and preserve the css styling of the contents.
*
* @param {Element} element The element for which context should be calculated.
* @param {boolean=} opt_forceRuleSetCacheUpdate Flag to force the internal
* cache of rulesets to refresh itself before we read the same.
* @param {boolean=} opt_copyBackgroundContext Flag indicating that if the
* {@code element} has a transparent background, background rules
* from the nearest ancestor element(s) that have background-color
* and/or background-image set should be copied.
* @return {string} String containing all CSS rules present in the original
* document, with modified selectors.
* @see goog.cssom.iframe.style.getBackgroundContext.
*/
goog.cssom.iframe.style.getElementContext = function(
element, opt_forceRuleSetCacheUpdate, opt_copyBackgroundContext) {
var sourceDocument = element.ownerDocument;
if (opt_forceRuleSetCacheUpdate) {
goog.cssom.iframe.style.ruleSetCache_.loadRuleSetsForDocument(
sourceDocument);
}
var ruleSets = goog.cssom.iframe.style.ruleSetCache_.getRuleSetsForDocument(
sourceDocument);
var elementAncestry = new goog.cssom.iframe.style.NodeAncestry_(element);
var bodySelectorPart = new goog.cssom.iframe.style.CssSelectorPart_('body');
for (var i = 0; i < ruleSets.length; i++) {
var ruleSet = ruleSets[i];
var selectors = ruleSet.selectors;
// Cache selectors.length since we may be adding rules in the loop.
var ruleCount = selectors.length;
for (var j = 0; j < ruleCount; j++) {
var selector = selectors[j];
// Test whether all or part of this selector would match
// this element or one of its ancestors
var match = selector.matchElementAncestry(elementAncestry);
if (match) {
var ruleIndex = match.selectorPartIndex;
var selectorParts = selector.parts;
var lastSelectorPartIndex = selectorParts.length - 1;
var selectorCopy;
if (match.elementIndex == elementAncestry.nodes.length - 1 ||
ruleIndex < lastSelectorPartIndex) {
// Either the first part(s) of the selector matched this element,
// or the first part(s) of the selector matched a parent element
// and there are more parts of the selector that could target
// children of this element.
// So we inject a new selector, replacing the part that matched this
// element with 'body' so it will continue to match.
var selectorPartsCopy = selectorParts.concat();
selectorPartsCopy.splice(0, ruleIndex + 1, bodySelectorPart);
selectorCopy = new goog.cssom.iframe.style.CssSelector_();
selectorCopy.parts = selectorPartsCopy;
selectors.push(selectorCopy);
} else if (ruleIndex > 0 && ruleIndex == lastSelectorPartIndex) {
// The rule didn't match this element, but the entire rule did
// match an ancestor element. In this case we want to copy
// just the last part of the rule, to give it a chance to be applied
// to additional matching elements inside this element.
// Example DOM structure: body > div.funky > ul > li#editme
// Example CSS selector: .funky ul
// New CSS selector: body ul
selectorCopy = new goog.cssom.iframe.style.CssSelector_();
selectorCopy.parts =
[bodySelectorPart, selectorParts[lastSelectorPartIndex]];
selectors.push(selectorCopy);
}
}
}
}
// Insert a new ruleset, setting the current inheritable styles of this
// element as the defaults for everything under in the frame.
var defaultPropertiesRuleSet = new goog.cssom.iframe.style.CssRuleSet_();
var computedStyle = goog.cssom.iframe.style.getComputedStyleObject_(element);
// Copy inheritable styles so they are applied to everything under HTML.
var htmlSelector = new goog.cssom.iframe.style.CssSelector_();
htmlSelector.parts = [new goog.cssom.iframe.style.CssSelectorPart_('html')];
defaultPropertiesRuleSet.selectors = [htmlSelector];
var defaultProperties = {};
for (var i = 0, prop; prop = goog.cssom.iframe.style.inheritedProperties_[i];
i++) {
defaultProperties[prop] = computedStyle[goog.string.toCamelCase(prop)];
}
defaultPropertiesRuleSet.setDeclarationTextFromObject(defaultProperties);
ruleSets.push(defaultPropertiesRuleSet);
var bodyRuleSet = new goog.cssom.iframe.style.CssRuleSet_();
var bodySelector = new goog.cssom.iframe.style.CssSelector_();
bodySelector.parts = [new goog.cssom.iframe.style.CssSelectorPart_('body')];
// Core set of sane property values for BODY, to prevent copied
// styles from completely breaking the display.
var bodyProperties = {
position: 'relative',
top: '0',
left: '0',
right: 'auto', // Override any existing right value so 'left' works.
display: 'block',
visibility: 'visible'
};
// Text formatting property values, to keep text nodes directly under BODY
// looking right.
for (i = 0; prop = goog.cssom.iframe.style.textProperties_[i]; i++) {
bodyProperties[prop] = computedStyle[goog.string.toCamelCase(prop)];
}
if (opt_copyBackgroundContext &&
goog.cssom.iframe.style.isTransparentValue_(
computedStyle['backgroundColor'])) {
// opt_useAncestorBackgroundRules means that, if the original element
// has a transparent background, background properties rules should be
// added to explicitly make the body have the same background appearance
// as in the original element, even if its positioned somewhere else
// in the DOM.
var bgProperties = goog.cssom.iframe.style.getBackgroundContext(element);
bodyProperties['background-color'] = bgProperties['backgroundColor'];
var elementBgImage = computedStyle['backgroundImage'];
if (!elementBgImage || elementBgImage == 'none') {
bodyProperties['background-image'] = bgProperties['backgroundImage'];
bodyProperties['background-repeat'] = bgProperties['backgroundRepeat'];
bodyProperties['background-position'] =
bgProperties['backgroundPosition'];
}
}
bodyRuleSet.setDeclarationTextFromObject(bodyProperties, true);
bodyRuleSet.selectors = [bodySelector];
ruleSets.push(bodyRuleSet);
// Write outputTextParts to doc.
var ruleSetStrings = [];
ruleCount = ruleSets.length;
for (i = 0; i < ruleCount; i++) {
ruleSets[i].writeToArray(ruleSetStrings);
}
return ruleSetStrings.join('');
};
/**
* Tests whether a value is equivalent to 'transparent'.
* @param {string} colorValue The value to test.
* @return {boolean} Whether the value is transparent.
* @private
*/
goog.cssom.iframe.style.isTransparentValue_ = function(colorValue) {
return colorValue == 'transparent' || colorValue == 'rgba(0, 0, 0, 0)';
};
/**
* Returns an object containing the set of computedStyle/currentStyle
* values for the given element. Note that this should be used with
* caution as it ignores the fact that currentStyle and computedStyle
* are not the same for certain properties.
*
* @param {Element} element The element whose computed style to return.
* @return {Object} Object containing style properties and values.
* @private
*/
goog.cssom.iframe.style.getComputedStyleObject_ = function(element) {
// Return an object containing the element's computedStyle/currentStyle.
// The resulting object can be re-used to read multiple properties, which
// is faster than calling goog.style.getComputedStyle every time.
return element.currentStyle ||
goog.dom.getOwnerDocument(element).defaultView.getComputedStyle(
element, '') ||
{};
};
/**
* RegExp that splits a value like "10px" or "-1em" into parts.
* @private
* @type {RegExp}
*/
goog.cssom.iframe.style.valueWithUnitsRegEx_ = /^(-?)([0-9]+)([a-z]*|%)/;
/**
* Given an object containing a set of styles, returns a two-element array
* containing the values of background-position-x and background-position-y.
* @param {Object} styleObject Object from which to read style properties.
* @return {Array<string>} The background-position values in the order [x, y].
* @private
*/
goog.cssom.iframe.style.getBackgroundXYValues_ = function(styleObject) {
// Gecko only has backgroundPosition, containing both values.
// IE has only backgroundPositionX/backgroundPositionY.
// WebKit has both.
if (styleObject['backgroundPositionY']) {
return [
styleObject['backgroundPositionX'], styleObject['backgroundPositionY']
];
} else {
return (styleObject['backgroundPosition'] || '0 0').split(' ');
}
};
/**
* Generates a set of CSS properties that can be used to make another
* element's background look like the background of a given element.
* This is useful when you want to copy the CSS context of an element,
* but the element's background is transparent. In the original context
* you would see the ancestor's backround color/image showing through,
* but in the new context there might be a something different underneath.
* Note that this assumes the element you're copying context from has a
* fairly standard positioning/layout - it assumes that when the element
* has a transparent background what you're going to see through it is its
* ancestors.
* @param {Element} element The element from which to copy background styles.
* @return {!Object} Object containing background* properties.
*/
goog.cssom.iframe.style.getBackgroundContext = function(element) {
var propertyValues = {'backgroundImage': 'none'};
var ancestor = element;
var currentIframeWindow;
// Walk up the DOM tree to find the ancestor nodes whose backgrounds
// may be visible underneath this element. Background-image and
// background-color don't have to come from the same node, but as soon
// an element with background-color is found there's no need to continue
// because backgrounds farther up the chain won't be visible.
// (This implementation is not sophisticated enough to handle opacity,
// or multple layered partially-transparent background images.)
while ((ancestor = /** @type {!Element} */ (ancestor.parentNode)) &&
ancestor.nodeType == goog.dom.NodeType.ELEMENT) {
var computedStyle =
goog.cssom.iframe.style.getComputedStyleObject_(ancestor);
// Copy background color if a non-transparent value is found.
var backgroundColorValue = computedStyle['backgroundColor'];
if (!goog.cssom.iframe.style.isTransparentValue_(backgroundColorValue)) {
propertyValues['backgroundColor'] = backgroundColorValue;
}
// If a background image value is found, copy background-image,
// background-repeat, and background-position.
if (computedStyle['backgroundImage'] &&
computedStyle['backgroundImage'] != 'none') {
propertyValues['backgroundImage'] = computedStyle['backgroundImage'];
propertyValues['backgroundRepeat'] = computedStyle['backgroundRepeat'];
// Calculate the offset between the original element and the element
// providing the background image, so the background position can be
// adjusted.
var relativePosition;
if (currentIframeWindow) {
relativePosition =
goog.style.getFramedPageOffset(element, currentIframeWindow);
var frameElement = currentIframeWindow.frameElement;
var iframeRelativePosition = goog.style.getRelativePosition(
/** @type {!Element} */ (frameElement), ancestor);
var iframeBorders = goog.style.getBorderBox(frameElement);
relativePosition.x += iframeRelativePosition.x + iframeBorders.left;
relativePosition.y += iframeRelativePosition.y + iframeBorders.top;
} else {
relativePosition = goog.style.getRelativePosition(element, ancestor);
}
var backgroundXYValues =
goog.cssom.iframe.style.getBackgroundXYValues_(computedStyle);
// Parse background-repeat-* values in the form "10px", and adjust them.
for (var i = 0; i < 2; i++) {
var positionValue = backgroundXYValues[i];
var coordinate = i == 0 ? 'X' : 'Y';
var positionProperty = 'backgroundPosition' + coordinate;
// relative position to its ancestor.
var positionValueParts =
goog.cssom.iframe.style.valueWithUnitsRegEx_.exec(positionValue);
if (positionValueParts) {
var value =
parseInt(positionValueParts[1] + positionValueParts[2], 10);
var units = positionValueParts[3];
// This only attempts to handle pixel values for now (plus
// '0anything', which is equivalent to 0px).
// TODO(user) Convert non-pixel values to pixels when possible.
if (value == 0 || units == 'px') {
value -=
(coordinate == 'X' ? relativePosition.x : relativePosition.y);
}
positionValue = value + units;
}
propertyValues[positionProperty] = positionValue;
}
propertyValues['backgroundPosition'] =
propertyValues['backgroundPositionX'] + ' ' +
propertyValues['backgroundPositionY'];
}
if (propertyValues['backgroundColor']) {
break;
}
if (ancestor.tagName == goog.dom.TagName.HTML) {
try {
currentIframeWindow = goog.dom.getWindow(
/** @type {Document} */ (ancestor.parentNode));
// This could theoretically throw a security exception if the parent
// iframe is in a different domain.
ancestor = currentIframeWindow.frameElement;
if (!ancestor) {
// Loop has reached the top level window.
break;
}
} catch (e) {
// We don't have permission to go up to the parent window, stop here.
break;
}
}
}
return propertyValues;
};