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-// Copyright 2014 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.
-
-/**
- * @fileoverview Low-level DOM traversal utility functions to find the
- * next (or previous) character, word, sentence, line, or paragraph,
- * in a completely stateless manner without actually manipulating the
- * selection.
- */
-
-goog.provide('cvox.TraverseUtil');
-
-goog.require('cvox.Cursor');
-goog.require('cvox.DomPredicates');
-goog.require('cvox.DomUtil');
-
-/**
- * Utility functions for stateless DOM traversal.
- * @constructor
- */
-cvox.TraverseUtil = function() {};
-
-/**
- * Gets the text representation of a node. This allows us to substitute
- * alt text, names, or titles for html elements that provide them.
- * @param {Node} node A DOM node.
- * @return {string} A text string representation of the node.
- */
-cvox.TraverseUtil.getNodeText = function(node) {
- if (node.constructor == Text) {
- return node.data;
- } else {
- return '';
- }
-};
-
-/**
- * Return true if a node should be treated as a leaf node, because
- * its children are properties of the object that shouldn't be traversed.
- *
- * TODO(dmazzoni): replace this with a predicate that detects nodes with
- * ARIA roles and other objects that have their own description.
- * For now we just detect a couple of common cases.
- *
- * @param {Node} node A DOM node.
- * @return {boolean} True if the node should be treated as a leaf node.
- */
-cvox.TraverseUtil.treatAsLeafNode = function(node) {
- return node.childNodes.length == 0 ||
- node.nodeName == 'SELECT' ||
- node.getAttribute('role') == 'listbox' ||
- node.nodeName == 'OBJECT';
-};
-
-/**
- * Return true only if a single character is whitespace.
- * From https://developer.mozilla.org/en/Whitespace_in_the_DOM,
- * whitespace is defined as one of the characters
- * "\t" TAB \u0009
- * "\n" LF \u000A
- * "\r" CR \u000D
- * " " SPC \u0020.
- *
- * @param {string} c A string containing a single character.
- * @return {boolean} True if the character is whitespace, otherwise false.
- */
-cvox.TraverseUtil.isWhitespace = function(c) {
- return (c == ' ' || c == '\n' || c == '\r' || c == '\t');
-};
-
-/**
- * Set the selection to the range between the given start and end cursors.
- * @param {cvox.Cursor} start The desired start of the selection.
- * @param {cvox.Cursor} end The desired end of the selection.
- * @return {Selection} the selection object.
- */
-cvox.TraverseUtil.setSelection = function(start, end) {
- var sel = window.getSelection();
- sel.removeAllRanges();
- var range = document.createRange();
- range.setStart(start.node, start.index);
- range.setEnd(end.node, end.index);
- sel.addRange(range);
-
- return sel;
-};
-
-// TODO(dtseng): Combine with cvox.DomUtil.hasContent.
-/**
- * Check if this DOM node has the attribute aria-hidden='true', which should
- * hide it from screen readers.
- * @param {Node} node An HTML DOM node.
- * @return {boolean} Whether or not the html node should be traversed.
- */
-cvox.TraverseUtil.isHidden = function(node) {
- if (node instanceof HTMLElement &&
- node.getAttribute('aria-hidden') == 'true') {
- return true;
- }
- switch (node.tagName) {
- case 'SCRIPT':
- case 'NOSCRIPT':
- return true;
- }
- return false;
-};
-
-/**
- * Moves the cursor forwards until it has crossed exactly one character.
- * @param {cvox.Cursor} cursor The cursor location where the search should
- * start. On exit, the cursor will be immediately to the right of the
- * character returned.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The character found, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.forwardsChar = function(
- cursor, elementsEntered, elementsLeft) {
- while (true) {
- // Move down until we get to a leaf node.
- var childNode = null;
- if (!cvox.TraverseUtil.treatAsLeafNode(cursor.node)) {
- for (var i = cursor.index; i < cursor.node.childNodes.length; i++) {
- var node = cursor.node.childNodes[i];
- if (cvox.TraverseUtil.isHidden(node)) {
- if (node instanceof HTMLElement) {
- elementsEntered.push(node);
- }
- continue;
- }
- if (cvox.DomUtil.isVisible(node, {checkAncestors: false})) {
- childNode = node;
- break;
- }
- }
- }
- if (childNode) {
- cursor.node = childNode;
- cursor.index = 0;
- cursor.text = cvox.TraverseUtil.getNodeText(cursor.node);
- if (cursor.node instanceof HTMLElement) {
- elementsEntered.push(cursor.node);
- }
- continue;
- }
-
- // Return the next character from this leaf node.
- if (cursor.index < cursor.text.length)
- return cursor.text[cursor.index++];
-
- // Move to the next sibling, going up the tree as necessary.
- while (cursor.node != null) {
- // Try to move to the next sibling.
- var siblingNode = null;
- for (var node = cursor.node.nextSibling;
- node != null;
- node = node.nextSibling) {
- if (cvox.TraverseUtil.isHidden(node)) {
- if (node instanceof HTMLElement) {
- elementsEntered.push(node);
- }
- continue;
- }
- if (cvox.DomUtil.isVisible(node, {checkAncestors: false})) {
- siblingNode = node;
- break;
- }
- }
- if (siblingNode) {
- if (cursor.node instanceof HTMLElement) {
- elementsLeft.push(cursor.node);
- }
-
- cursor.node = siblingNode;
- cursor.text = cvox.TraverseUtil.getNodeText(siblingNode);
- cursor.index = 0;
-
- if (cursor.node instanceof HTMLElement) {
- elementsEntered.push(cursor.node);
- }
-
- break;
- }
-
- // Otherwise, move to the parent.
- if (cursor.node.parentNode &&
- cursor.node.parentNode.constructor != HTMLBodyElement) {
- if (cursor.node instanceof HTMLElement) {
- elementsLeft.push(cursor.node);
- }
- cursor.node = cursor.node.parentNode;
- cursor.text = null;
- cursor.index = 0;
- } else {
- return null;
- }
- }
- }
-};
-
-/**
- * Moves the cursor backwards until it has crossed exactly one character.
- * @param {cvox.Cursor} cursor The cursor location where the search should
- * start. On exit, the cursor will be immediately to the left of the
- * character returned.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The previous character, or null if the top of the
- * document has been reached.
- */
-cvox.TraverseUtil.backwardsChar = function(
- cursor, elementsEntered, elementsLeft) {
- while (true) {
- // Move down until we get to a leaf node.
- var childNode = null;
- if (!cvox.TraverseUtil.treatAsLeafNode(cursor.node)) {
- for (var i = cursor.index - 1; i >= 0; i--) {
- var node = cursor.node.childNodes[i];
- if (cvox.TraverseUtil.isHidden(node)) {
- if (node instanceof HTMLElement) {
- elementsEntered.push(node);
- }
- continue;
- }
- if (cvox.DomUtil.isVisible(node, {checkAncestors: false})) {
- childNode = node;
- break;
- }
- }
- }
- if (childNode) {
- cursor.node = childNode;
- cursor.text = cvox.TraverseUtil.getNodeText(cursor.node);
- if (cursor.text.length)
- cursor.index = cursor.text.length;
- else
- cursor.index = cursor.node.childNodes.length;
- if (cursor.node instanceof HTMLElement) {
- elementsEntered.push(cursor.node);
- }
- continue;
- }
-
- // Return the previous character from this leaf node.
- if (cursor.text.length > 0 && cursor.index > 0) {
- return cursor.text[--cursor.index];
- }
-
- // Move to the previous sibling, going up the tree as necessary.
- while (true) {
- // Try to move to the previous sibling.
- var siblingNode = null;
- for (var node = cursor.node.previousSibling;
- node != null;
- node = node.previousSibling) {
- if (cvox.TraverseUtil.isHidden(node)) {
- if (node instanceof HTMLElement) {
- elementsEntered.push(node);
- }
- continue;
- }
- if (cvox.DomUtil.isVisible(node, {checkAncestors: false})) {
- siblingNode = node;
- break;
- }
- }
- if (siblingNode) {
- if (cursor.node instanceof HTMLElement) {
- elementsLeft.push(cursor.node);
- }
-
- cursor.node = siblingNode;
- cursor.text = cvox.TraverseUtil.getNodeText(siblingNode);
- if (cursor.text.length)
- cursor.index = cursor.text.length;
- else
- cursor.index = cursor.node.childNodes.length;
-
- if (cursor.node instanceof HTMLElement) {
- elementsEntered.push(cursor.node);
- }
- break;
- }
-
- // Otherwise, move to the parent.
- if (cursor.node.parentNode &&
- cursor.node.parentNode.constructor != HTMLBodyElement) {
- if (cursor.node instanceof HTMLElement) {
- elementsLeft.push(cursor.node);
- }
- cursor.node = cursor.node.parentNode;
- cursor.text = null;
- cursor.index = 0;
- } else {
- return null;
- }
- }
- }
-};
-
-/**
- * Finds the next character, starting from endCursor. Upon exit, startCursor
- * and endCursor will surround the next character. If skipWhitespace is
- * true, will skip until a real character is found. Otherwise, it will
- * attempt to select all of the whitespace between the initial position
- * of endCursor and the next non-whitespace character.
- * @param {!cvox.Cursor} startCursor On exit, points to the position before
- * the char.
- * @param {!cvox.Cursor} endCursor The position to start searching for the next
- * char. On exit, will point to the position past the char.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * initial and final cursor position will be pushed onto this array.
- * @param {boolean} skipWhitespace If true, will keep scanning until a
- * non-whitespace character is found.
- * @return {?string} The next char, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextChar = function(
- startCursor, endCursor, elementsEntered, elementsLeft, skipWhitespace) {
-
- // Save the starting position and get the first character.
- startCursor.copyFrom(endCursor);
- var c = cvox.TraverseUtil.forwardsChar(
- endCursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
-
- // Keep track of whether the first character was whitespace.
- var initialWhitespace = cvox.TraverseUtil.isWhitespace(c);
-
- // Keep scanning until we find a non-whitespace or non-skipped character.
- while ((cvox.TraverseUtil.isWhitespace(c)) ||
- (cvox.TraverseUtil.isHidden(endCursor.node))) {
- c = cvox.TraverseUtil.forwardsChar(
- endCursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- }
- if (skipWhitespace || !initialWhitespace) {
- // If skipWhitepace is true, or if the first character we encountered
- // was not whitespace, return that non-whitespace character.
- startCursor.copyFrom(endCursor);
- startCursor.index--;
- return c;
- }
- else {
- for (var i = 0; i < elementsEntered.length; i++) {
- if (cvox.TraverseUtil.isHidden(elementsEntered[i])) {
- // We need to make sure that startCursor and endCursor aren't
- // surrounding a skippable node.
- endCursor.index--;
- startCursor.copyFrom(endCursor);
- startCursor.index--;
- return ' ';
- }
- }
- // Otherwise, return all of the whitespace before that last character.
- endCursor.index--;
- return ' ';
- }
-};
-
-/**
- * Finds the previous character, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous character.
- * If skipWhitespace is true, will skip until a real character is found.
- * Otherwise, it will attempt to select all of the whitespace between
- * the initial position of endCursor and the next non-whitespace character.
- * @param {!cvox.Cursor} startCursor The position to start searching for the
- * char. On exit, will point to the position before the char.
- * @param {!cvox.Cursor} endCursor The position to start searching for the next
- * char. On exit, will point to the position past the char.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * initial and final cursor position will be pushed onto this array.
- * @param {boolean} skipWhitespace If true, will keep scanning until a
- * non-whitespace character is found.
- * @return {?string} The previous char, or null if the top of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousChar = function(
- startCursor, endCursor, elementsEntered, elementsLeft, skipWhitespace) {
-
- // Save the starting position and get the first character.
- endCursor.copyFrom(startCursor);
- var c = cvox.TraverseUtil.backwardsChar(
- startCursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
-
- // Keep track of whether the first character was whitespace.
- var initialWhitespace = cvox.TraverseUtil.isWhitespace(c);
-
- // Keep scanning until we find a non-whitespace or non-skipped character.
- while ((cvox.TraverseUtil.isWhitespace(c)) ||
- (cvox.TraverseUtil.isHidden(startCursor.node))) {
- c = cvox.TraverseUtil.backwardsChar(
- startCursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- }
- if (skipWhitespace || !initialWhitespace) {
- // If skipWhitepace is true, or if the first character we encountered
- // was not whitespace, return that non-whitespace character.
- endCursor.copyFrom(startCursor);
- endCursor.index++;
- return c;
- } else {
- for (var i = 0; i < elementsEntered.length; i++) {
- if (cvox.TraverseUtil.isHidden(elementsEntered[i])) {
- startCursor.index++;
- endCursor.copyFrom(startCursor);
- endCursor.index++;
- return ' ';
- }
- }
- // Otherwise, return all of the whitespace before that last character.
- startCursor.index++;
- return ' ';
- }
-};
-
-/**
- * Finds the next word, starting from endCursor. Upon exit, startCursor
- * and endCursor will surround the next word. A word is defined to be
- * a string of 1 or more non-whitespace characters in the same DOM node.
- * @param {cvox.Cursor} startCursor On exit, will point to the beginning of the
- * word returned.
- * @param {cvox.Cursor} endCursor The position to start searching for the next
- * word. On exit, will point to the end of the word returned.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The next word, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextWord = function(startCursor, endCursor,
- elementsEntered, elementsLeft) {
-
- // Find the first non-whitespace or non-skipped character.
- var cursor = endCursor.clone();
- var c = cvox.TraverseUtil.forwardsChar(cursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- while ((cvox.TraverseUtil.isWhitespace(c)) ||
- (cvox.TraverseUtil.isHidden(cursor.node))) {
- c = cvox.TraverseUtil.forwardsChar(cursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- }
-
- // Set startCursor to the position immediately before the first
- // character in our word. It's safe to decrement |index| because
- // forwardsChar guarantees that the cursor will be immediately to the
- // right of the returned character on exit.
- startCursor.copyFrom(cursor);
- startCursor.index--;
-
- // Keep building up our word until we reach a whitespace character or
- // would cross a tag. Don't actually return any tags crossed, because this
- // word goes up until the tag boundary but not past it.
- endCursor.copyFrom(cursor);
- var word = c;
- var newEntered = [];
- var newLeft = [];
- c = cvox.TraverseUtil.forwardsChar(cursor, newEntered, newLeft);
- if (c == null) {
- return word;
- }
- while (!cvox.TraverseUtil.isWhitespace(c) &&
- newEntered.length == 0 &&
- newLeft == 0) {
- word += c;
- endCursor.copyFrom(cursor);
- c = cvox.TraverseUtil.forwardsChar(cursor, newEntered, newLeft);
- if (c == null) {
- return word;
- }
- }
-
- return word;
-};
-
-/**
- * Finds the previous word, starting from startCursor. Upon exit, startCursor
- * and endCursor will surround the previous word. A word is defined to be
- * a string of 1 or more non-whitespace characters in the same DOM node.
- * @param {cvox.Cursor} startCursor The position to start searching for the
- * previous word. On exit, will point to the beginning of the
- * word returned.
- * @param {cvox.Cursor} endCursor On exit, will point to the end of the
- * word returned.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The previous word, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousWord = function(startCursor, endCursor,
- elementsEntered, elementsLeft) {
- // Find the first non-whitespace or non-skipped character.
- var cursor = startCursor.clone();
- var c = cvox.TraverseUtil.backwardsChar(
- cursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- while ((cvox.TraverseUtil.isWhitespace(c) ||
- (cvox.TraverseUtil.isHidden(cursor.node)))) {
- c = cvox.TraverseUtil.backwardsChar(cursor, elementsEntered, elementsLeft);
- if (c == null)
- return null;
- }
-
- // Set endCursor to the position immediately after the first
- // character we've found (the last character of the word, since we're
- // searching backwards).
- endCursor.copyFrom(cursor);
- endCursor.index++;
-
- // Keep building up our word until we reach a whitespace character or
- // would cross a tag. Don't actually return any tags crossed, because this
- // word goes up until the tag boundary but not past it.
- startCursor.copyFrom(cursor);
- var word = c;
- var newEntered = [];
- var newLeft = [];
- c = cvox.TraverseUtil.backwardsChar(cursor, newEntered, newLeft);
- if (c == null)
- return word;
- while (!cvox.TraverseUtil.isWhitespace(c) &&
- newEntered.length == 0 &&
- newLeft.length == 0) {
- word = c + word;
- startCursor.copyFrom(cursor);
-
- c = cvox.TraverseUtil.backwardsChar(cursor, newEntered, newLeft);
- if (c == null)
- return word;
- }
-
- return word;
-};
-
-
-/**
- * Given elements entered and left, and break tags, returns true if the
- * current word should break.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {Object<boolean>} breakTags Associative array of tags that should
- * break.
- * @return {boolean} True if elementsEntered or elementsLeft include an
- * element with one of these tags.
- */
-cvox.TraverseUtil.includesBreakTagOrSkippedNode = function(
- elementsEntered, elementsLeft, breakTags) {
- for (var i = 0; i < elementsEntered.length; i++) {
- if (cvox.TraverseUtil.isHidden(elementsEntered[i])) {
- return true;
- }
- var style = window.getComputedStyle(elementsEntered[i], null);
- if ((style && style.display != 'inline') ||
- breakTags[elementsEntered[i].tagName]) {
- return true;
- }
- }
- for (i = 0; i < elementsLeft.length; i++) {
- var style = window.getComputedStyle(elementsLeft[i], null);
- if ((style && style.display != 'inline') ||
- breakTags[elementsLeft[i].tagName]) {
- return true;
- }
- }
- return false;
-};
-
-
-/**
- * Finds the next sentence, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next sentence.
- *
- * @param {cvox.Cursor} startCursor On exit, marks the beginning of the
- * sentence.
- * @param {cvox.Cursor} endCursor The position to start searching for the next
- * sentence. On exit, will point to the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {Object<boolean>} breakTags Associative array of tags that should
- * break the sentence.
- * @return {?string} The next sentence, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextSentence = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakTags) {
- return cvox.TraverseUtil.getNextString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- if (str.substr(-1) == '.')
- return true;
- return cvox.TraverseUtil.includesBreakTagOrSkippedNode(
- elementsEntered, elementsLeft, breakTags);
- });
-};
-
-/**
- * Finds the previous sentence, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous sentence.
- *
- * @param {cvox.Cursor} startCursor The position to start searching for the next
- * sentence. On exit, will point to the start of the returned string.
- * @param {cvox.Cursor} endCursor On exit, the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {Object<boolean>} breakTags Associative array of tags that should
- * break the sentence.
- * @return {?string} The previous sentence, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousSentence = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakTags) {
- return cvox.TraverseUtil.getPreviousString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- if (word.substr(-1) == '.')
- return true;
- return cvox.TraverseUtil.includesBreakTagOrSkippedNode(
- elementsEntered, elementsLeft, breakTags);
- });
-};
-
-/**
- * Finds the next line, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next line.
- *
- * @param {cvox.Cursor} startCursor On exit, marks the beginning of the line.
- * @param {cvox.Cursor} endCursor The position to start searching for the next
- * line. On exit, will point to the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {Object<boolean>} breakTags Associative array of tags that should
- * break the line.
- * @return {?string} The next line, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextLine = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakTags) {
- var range = document.createRange();
- var currentRect = null;
- var rightMostRect = null;
- var prevCursor = endCursor.clone();
- return cvox.TraverseUtil.getNextString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- range.setStart(startCursor.node, startCursor.index);
- range.setEnd(endCursor.node, endCursor.index);
- var currentRect = range.getBoundingClientRect();
- if (!rightMostRect) {
- rightMostRect = currentRect;
- }
-
- // Break at new lines except when within a link.
- if (currentRect.bottom != rightMostRect.bottom &&
- !cvox.DomPredicates.linkPredicate(cvox.DomUtil.getAncestors(
- endCursor.node))) {
- endCursor.copyFrom(prevCursor);
- return true;
- }
-
- rightMostRect = currentRect;
- prevCursor.copyFrom(endCursor);
-
- return cvox.TraverseUtil.includesBreakTagOrSkippedNode(
- elementsEntered, elementsLeft, breakTags);
- });
-};
-
-/**
- * Finds the previous line, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous line.
- *
- * @param {cvox.Cursor} startCursor The position to start searching for the next
- * line. On exit, will point to the start of the returned string.
- * @param {cvox.Cursor} endCursor On exit, the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {Object<boolean>} breakTags Associative array of tags that should
- * break the line.
- * @return {?string} The previous line, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousLine = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakTags) {
- var range = document.createRange();
- var currentRect = null;
- var leftMostRect = null;
- var prevCursor = startCursor.clone();
- return cvox.TraverseUtil.getPreviousString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- range.setStart(startCursor.node, startCursor.index);
- range.setEnd(endCursor.node, endCursor.index);
- var currentRect = range.getBoundingClientRect();
- if (!leftMostRect) {
- leftMostRect = currentRect;
- }
-
- // Break at new lines except when within a link.
- if (currentRect.top != leftMostRect.top &&
- !cvox.DomPredicates.linkPredicate(cvox.DomUtil.getAncestors(
- startCursor.node))) {
- startCursor.copyFrom(prevCursor);
- return true;
- }
-
- leftMostRect = currentRect;
- prevCursor.copyFrom(startCursor);
-
- return cvox.TraverseUtil.includesBreakTagOrSkippedNode(
- elementsEntered, elementsLeft, breakTags);
- });
-};
-
-/**
- * Finds the next paragraph, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next paragraph.
- *
- * @param {cvox.Cursor} startCursor On exit, marks the beginning of the
- * paragraph.
- * @param {cvox.Cursor} endCursor The position to start searching for the next
- * paragraph. On exit, will point to the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The next paragraph, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextParagraph = function(startCursor, endCursor,
- elementsEntered, elementsLeft) {
- return cvox.TraverseUtil.getNextString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- for (var i = 0; i < elementsEntered.length; i++) {
- if (cvox.TraverseUtil.isHidden(elementsEntered[i])) {
- return true;
- }
- var style = window.getComputedStyle(elementsEntered[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- for (i = 0; i < elementsLeft.length; i++) {
- var style = window.getComputedStyle(elementsLeft[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Finds the previous paragraph, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the previous paragraph.
- *
- * @param {cvox.Cursor} startCursor The position to start searching for the next
- * paragraph. On exit, will point to the start of the returned string.
- * @param {cvox.Cursor} endCursor On exit, the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @return {?string} The previous paragraph, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousParagraph = function(
- startCursor, endCursor, elementsEntered, elementsLeft) {
- return cvox.TraverseUtil.getPreviousString(
- startCursor, endCursor, elementsEntered, elementsLeft,
- function(str, word, elementsEntered, elementsLeft) {
- for (var i = 0; i < elementsEntered.length; i++) {
- if (cvox.TraverseUtil.isHidden(elementsEntered[i])) {
- return true;
- }
- var style = window.getComputedStyle(elementsEntered[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- for (i = 0; i < elementsLeft.length; i++) {
- var style = window.getComputedStyle(elementsLeft[i], null);
- if (style && style.display != 'inline') {
- return true;
- }
- }
- return false;
- });
-};
-
-/**
- * Customizable function to return the next string of words in the DOM, based
- * on provided functions to decide when to break one string and start
- * the next. This can be used to get the next sentence, line, paragraph,
- * or potentially other granularities.
- *
- * Finds the next contiguous string, starting from endCursor. Upon exit,
- * startCursor and endCursor will surround the next string.
- *
- * The breakBefore function takes four parameters, and
- * should return true if the string should be broken before the proposed
- * next word:
- * str The string so far.
- * word The next word to be added.
- * elementsEntered The elements entered in reaching this next word.
- * elementsLeft The elements left in reaching this next word.
- *
- * @param {cvox.Cursor} startCursor On exit, will point to the beginning of the
- * next string.
- * @param {cvox.Cursor} endCursor The position to start searching for the next
- * string. On exit, will point to the end of the returned string.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {function(string, string, Array<Element>, Array<Element>)}
- * breakBefore Function that takes the string so far, next word to be
- * added, and elements entered and left, and returns true if the string
- * should be ended before adding this word.
- * @return {?string} The next string, or null if the bottom of the
- * document has been reached.
- */
-cvox.TraverseUtil.getNextString = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakBefore) {
- // Get the first word and set the start cursor to the start of the
- // first word.
- var wordStartCursor = endCursor.clone();
- var wordEndCursor = endCursor.clone();
- var newEntered = [];
- var newLeft = [];
- var str = '';
- var word = cvox.TraverseUtil.getNextWord(
- wordStartCursor, wordEndCursor, newEntered, newLeft);
- if (word == null)
- return null;
- startCursor.copyFrom(wordStartCursor);
-
- // Always add the first word when the string is empty, and then keep
- // adding more words as long as breakBefore returns false
- while (!str || !breakBefore(str, word, newEntered, newLeft)) {
- // Append this word, set the end cursor to the end of this word, and
- // update the returned list of nodes crossed to include ones we crossed
- // in reaching this word.
- if (str)
- str += ' ';
- str += word;
- elementsEntered = elementsEntered.concat(newEntered);
- elementsLeft = elementsLeft.concat(newLeft);
- endCursor.copyFrom(wordEndCursor);
-
- // Get the next word and go back to the top of the loop.
- newEntered = [];
- newLeft = [];
- word = cvox.TraverseUtil.getNextWord(
- wordStartCursor, wordEndCursor, newEntered, newLeft);
- if (word == null)
- return str;
- }
-
- return str;
-};
-
-/**
- * Customizable function to return the previous string of words in the DOM,
- * based on provided functions to decide when to break one string and start
- * the next. See getNextString, above, for more details.
- *
- * Finds the previous contiguous string, starting from startCursor. Upon exit,
- * startCursor and endCursor will surround the next string.
- *
- * @param {cvox.Cursor} startCursor The position to start searching for the
- * previous string. On exit, will point to the beginning of the
- * string returned.
- * @param {cvox.Cursor} endCursor On exit, will point to the end of the
- * string returned.
- * @param {Array<Element>} elementsEntered Any HTML elements entered.
- * @param {Array<Element>} elementsLeft Any HTML elements left.
- * @param {function(string, string, Array<Element>, Array<Element>)}
- * breakBefore Function that takes the string so far, the word to be
- * added, and nodes crossed, and returns true if the string should be
- * ended before adding this word.
- * @return {?string} The next string, or null if the top of the
- * document has been reached.
- */
-cvox.TraverseUtil.getPreviousString = function(
- startCursor, endCursor, elementsEntered, elementsLeft, breakBefore) {
- // Get the first word and set the end cursor to the end of the
- // first word.
- var wordStartCursor = startCursor.clone();
- var wordEndCursor = startCursor.clone();
- var newEntered = [];
- var newLeft = [];
- var str = '';
- var word = cvox.TraverseUtil.getPreviousWord(
- wordStartCursor, wordEndCursor, newEntered, newLeft);
- if (word == null)
- return null;
- endCursor.copyFrom(wordEndCursor);
-
- // Always add the first word when the string is empty, and then keep
- // adding more words as long as breakBefore returns false
- while (!str || !breakBefore(str, word, newEntered, newLeft)) {
- // Prepend this word, set the start cursor to the start of this word, and
- // update the returned list of nodes crossed to include ones we crossed
- // in reaching this word.
- if (str)
- str = ' ' + str;
- str = word + str;
- elementsEntered = elementsEntered.concat(newEntered);
- elementsLeft = elementsLeft.concat(newLeft);
- startCursor.copyFrom(wordStartCursor);
-
- // Get the previous word and go back to the top of the loop.
- newEntered = [];
- newLeft = [];
- word = cvox.TraverseUtil.getPreviousWord(
- wordStartCursor, wordEndCursor, newEntered, newLeft);
- if (word == null)
- return str;
- }
-
- return str;
-};