pjs/toolkit/spatial-navigation/SpatialNavigation.js

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JavaScript

/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Spatial Navigation.
*
* The Initial Developer of the Original Code is Mozilla Corporation
* Portions created by the Initial Developer are Copyright (C) 2008
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Doug Turner <dougt@meer.net> (Original Author)
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/**
*
* Import this module through
*
* Components.utils.import("resource://gre/modules/SpatialNavigation.js");
*
* Usage: (Literal class)
*
* SpatialNavigation(browser_element, optional_callback);
*
* optional_callback will be called when a new element is focused.
*
* function optional_callback(element) {}
*
*/
var EXPORTED_SYMBOLS = ["SpatialNavigation"];
var SpatialNavigation = {
init: function(browser, callback) {
browser.addEventListener("keypress", function (event) { _onInputKeyPress(event, callback) }, true);
},
uninit: function() {
}
};
// Private stuff
const Cc = Components.classes;
const Ci = Components.interfaces;
function dump(msg)
{
var console = Cc["@mozilla.org/consoleservice;1"].getService(Ci.nsIConsoleService);
console.logStringMessage("*** SNAV: " + msg);
}
var gDirectionalBias = 10;
var gRectFudge = 1;
// modifier values
const kAlt = "alt";
const kShift = "shift";
const kCtrl = "ctrl";
const kNone = "none";
function _onInputKeyPress (event, callback) {
// If it isn't enabled, bail.
if (!PrefObserver['enabled'])
return;
// Use whatever key value is available (either keyCode or charCode).
// It might be useful for addons or whoever wants to set different
// key to be used here (e.g. "a", "F1", "arrowUp", ...).
var key = event.which || event.keyCode;
if (key != PrefObserver['keyCodeDown'] &&
key != PrefObserver['keyCodeRight'] &&
key != PrefObserver['keyCodeUp'] &&
key != PrefObserver['keyCodeLeft'])
return;
// If it is not using the modifiers it should, bail.
if (!event.altKey && PrefObserver['modifierAlt'])
return;
if (!event.shiftKey && PrefObserver['modifierShift'])
return;
if (!event.crtlKey && PrefObserver['modifierCtrl'])
return;
// In some special cases where charCode is equal to one of the default arrow keyCodes we
// should bail.
if (!event.keyCode &&
(key == Ci.nsIDOMKeyEvent.DOM_VK_LEFT || key == Ci.nsIDOMKeyEvent.DOM_VK_DOWN ||
key == Ci.nsIDOMKeyEvent.DOM_VK_RIGHT || key == Ci.nsIDOMKeyEvent.DOM_VK_UP))
return;
var target = event.target;
var doc = target.ownerDocument;
// If it is XUL content (e.g. about:config), bail.
if (!PrefObserver['xulContentEnabled'] && doc instanceof Ci.nsIDOMXULDocument)
return ;
// check to see if we are in a textarea or text input element, and if so,
// ensure that we let the arrow keys work properly.
if (target instanceof Ci.nsIDOMHTMLHtmlElement) {
_focusNextUsingCmdDispatcher(key, callback);
return;
}
if ((target instanceof Ci.nsIDOMHTMLInputElement && (target.type == "text" || target.type == "password")) ||
target instanceof Ci.nsIDOMHTMLTextAreaElement ) {
// if there is any selection at all, just ignore
if (target.selectionEnd - target.selectionStart > 0)
return;
// if there is no text, there is nothing special to do.
if (target.textLength > 0) {
if (key == PrefObserver['keyCodeRight'] ||
key == PrefObserver['keyCodeDown'] ) {
// we are moving forward into the document
if (target.textLength != target.selectionEnd)
return;
}
else
{
// we are at the start of the text, okay to move
if (target.selectionStart != 0)
return;
}
}
}
// Check to see if we are in a select
if (target instanceof Ci.nsIDOMHTMLSelectElement)
{
if (key == PrefObserver['keyCodeDown']) {
if (target.selectedIndex + 1 < target.length)
return;
}
if (key == PrefObserver['keyCodeUp']) {
if (target.selectedIndex > 0)
return;
}
}
function snavfilter(node) {
if (node instanceof Ci.nsIDOMHTMLLinkElement ||
node instanceof Ci.nsIDOMHTMLAnchorElement) {
// if a anchor doesn't have a href, don't target it.
if (node.href == "")
return Ci.nsIDOMNodeFilter.FILTER_SKIP;
return Ci.nsIDOMNodeFilter.FILTER_ACCEPT;
}
if ((node instanceof Ci.nsIDOMHTMLButtonElement ||
node instanceof Ci.nsIDOMHTMLInputElement ||
node instanceof Ci.nsIDOMHTMLLinkElement ||
node instanceof Ci.nsIDOMHTMLOptGroupElement ||
node instanceof Ci.nsIDOMHTMLSelectElement ||
node instanceof Ci.nsIDOMHTMLTextAreaElement) &&
node.disabled == false)
return Ci.nsIDOMNodeFilter.FILTER_ACCEPT;
return Ci.nsIDOMNodeFilter.FILTER_SKIP;
}
var bestElementToFocus = null;
var distanceToBestElement = Infinity;
var focusedRect = _inflateRect(target.getBoundingClientRect(),
- gRectFudge);
var treeWalker = doc.createTreeWalker(doc, Ci.nsIDOMNodeFilter.SHOW_ELEMENT, snavfilter, false);
var nextNode;
while ((nextNode = treeWalker.nextNode())) {
if (nextNode == target)
continue;
var nextRect = _inflateRect(nextNode.getBoundingClientRect(),
- gRectFudge);
if (! _isRectInDirection(key, focusedRect, nextRect))
continue;
var distance = _spatialDistance(key, focusedRect, nextRect);
//dump("looking at: " + nextNode + " " + distance);
if (distance <= distanceToBestElement && distance > 0) {
distanceToBestElement = distance;
bestElementToFocus = nextNode;
}
}
if (bestElementToFocus != null) {
//dump("focusing element " + bestElementToFocus.nodeName + " " + bestElementToFocus) + "id=" + bestElementToFocus.getAttribute("id");
// Wishing we could do element.focus()
doc.defaultView.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindowUtils).focus(bestElementToFocus);
// if it is a text element, select all.
if((bestElementToFocus instanceof Ci.nsIDOMHTMLInputElement && (bestElementToFocus.type == "text" || bestElementToFocus.type == "password")) ||
bestElementToFocus instanceof Ci.nsIDOMHTMLTextAreaElement ) {
bestElementToFocus.selectionStart = 0;
bestElementToFocus.selectionEnd = bestElementToFocus.textLength;
}
if (callback != undefined)
callback(bestElementToFocus);
} else {
// couldn't find anything. just advance and hope.
_focusNextUsingCmdDispatcher(key, callback);
}
event.preventDefault();
event.stopPropagation();
}
function _focusNextUsingCmdDispatcher(key, callback) {
var windowMediator = Cc['@mozilla.org/appshell/window-mediator;1'].getService(Ci.nsIWindowMediator);
var window = windowMediator.getMostRecentWindow("navigator:browser");
if (key == PrefObserver['keyCodeRight'] || key == PrefObserver['keyCodeDown']) {
window.document.commandDispatcher.advanceFocus();
} else {
window.document.commandDispatcher.rewindFocus();
}
if (callback != undefined)
callback(null);
}
function _isRectInDirection(key, focusedRect, anotherRect)
{
if (key == PrefObserver['keyCodeLeft']) {
return (anotherRect.left < focusedRect.left);
}
if (key == PrefObserver['keyCodeRight']) {
return (anotherRect.right > focusedRect.right);
}
if (key == PrefObserver['keyCodeUp']) {
return (anotherRect.top < focusedRect.top);
}
if (key == PrefObserver['keyCodeDown']) {
return (anotherRect.bottom > focusedRect.bottom);
}
return false;
}
function _inflateRect(rect, value)
{
var newRect = new Object();
newRect.left = rect.left - value;
newRect.top = rect.top - value;
newRect.right = rect.right + value;
newRect.bottom = rect.bottom + value;
return newRect;
}
function _containsRect(a, b)
{
return ( (b.left <= a.right) &&
(b.right >= a.left) &&
(b.top <= a.bottom) &&
(b.bottom >= a.top) );
}
function _spatialDistance(key, a, b)
{
var inlineNavigation = false;
var mx, my, nx, ny;
if (key == PrefObserver['keyCodeLeft']) {
// |---|
// |---|
//
// |---| |---|
// |---| |---|
//
// |---|
// |---|
//
if (a.top > b.bottom) {
// the b rect is above a.
mx = a.left;
my = a.top;
nx = b.right;
ny = b.bottom;
}
else if (a.bottom < b.top) {
// the b rect is below a.
mx = a.left;
my = a.bottom;
nx = b.right;
ny = b.top;
}
else {
mx = a.left;
my = 0;
nx = b.right;
ny = 0;
}
} else if (key == PrefObserver['keyCodeRight']) {
// |---|
// |---|
//
// |---| |---|
// |---| |---|
//
// |---|
// |---|
//
if (a.top > b.bottom) {
// the b rect is above a.
mx = a.right;
my = a.top;
nx = b.left;
ny = b.bottom;
}
else if (a.bottom < b.top) {
// the b rect is below a.
mx = a.right;
my = a.bottom;
nx = b.left;
ny = b.top;
} else {
mx = a.right;
my = 0;
nx = b.left;
ny = 0;
}
} else if (key == PrefObserver['keyCodeUp']) {
// |---| |---| |---|
// |---| |---| |---|
//
// |---|
// |---|
//
if (a.left > b.right) {
// the b rect is to the left of a.
mx = a.left;
my = a.top;
nx = b.right;
ny = b.bottom;
} else if (a.right < b.left) {
// the b rect is to the right of a
mx = a.right;
my = a.top;
nx = b.left;
ny = b.bottom;
} else {
// both b and a share some common x's.
mx = 0;
my = a.top;
nx = 0;
ny = b.bottom;
}
} else if (key == PrefObserver['keyCodeDown']) {
// |---|
// |---|
//
// |---| |---| |---|
// |---| |---| |---|
//
if (a.left > b.right) {
// the b rect is to the left of a.
mx = a.left;
my = a.bottom;
nx = b.right;
ny = b.top;
} else if (a.right < b.left) {
// the b rect is to the right of a
mx = a.right;
my = a.bottom;
nx = b.left;
ny = b.top;
} else {
// both b and a share some common x's.
mx = 0;
my = a.bottom;
nx = 0;
ny = b.top;
}
}
var scopedRect = _inflateRect(a, gRectFudge);
if (key == PrefObserver['keyCodeLeft'] ||
key == PrefObserver['keyCodeRight']) {
scopedRect.left = 0;
scopedRect.right = Infinity;
inlineNavigation = _containsRect(scopedRect, b);
}
else if (key == PrefObserver['keyCodeUp'] ||
key == PrefObserver['keyCodeDown']) {
scopedRect.top = 0;
scopedRect.bottom = Infinity;
inlineNavigation = _containsRect(scopedRect, b);
}
var d = Math.pow((mx-nx), 2) + Math.pow((my-ny), 2);
// prefer elements directly aligned with the focused element
if (inlineNavigation)
d /= gDirectionalBias;
return d;
}
// Snav preference observer
PrefObserver = {
register: function()
{
this.prefService = Cc["@mozilla.org/preferences-service;1"]
.getService(Ci.nsIPrefService);
this._branch = this.prefService.getBranch("snav.");
this._branch.QueryInterface(Ci.nsIPrefBranch2);
this._branch.addObserver("", this, false);
// set current or default pref values
this.observe(null, "nsPref:changed", "enabled");
this.observe(null, "nsPref:changed", "xulContentEnabled");
this.observe(null, "nsPref:changed", "keyCode.modifier");
this.observe(null, "nsPref:changed", "keyCode.right");
this.observe(null, "nsPref:changed", "keyCode.up");
this.observe(null, "nsPref:changed", "keyCode.down");
this.observe(null, "nsPref:changed", "keyCode.left");
},
observe: function(aSubject, aTopic, aData)
{
if(aTopic != "nsPref:changed")
return;
// aSubject is the nsIPrefBranch we're observing (after appropriate QI)
// aData is the name of the pref that's been changed (relative to aSubject)
switch (aData) {
case "enabled":
try {
this.enabled = this._branch.getBoolPref("enabled");
} catch(e) {
this.enabled = false;
}
break;
case "xulContentEnabled":
try {
this.xulContentEnabled = this._branch.getBoolPref("xulContentEnabled");
} catch(e) {
this.xulContentEnabled = false;
}
break;
case "keyCode.modifier":
try {
this.keyCodeModifier = this._branch.getCharPref("keyCode.modifier");
// resetting modifiers
this.modifierAlt = false;
this.modifierShift = false;
this.modifierCtrl = false;
if (this.keyCodeModifier != this.kNone)
{
// use are using '+' as a separator in about:config.
var mods = this.keyCodeModifier.split(/\++/);
for (var i = 0; i < mods.length; i++) {
var mod = mods[i].toLowerCase();
if (mod == "")
continue;
else if (mod == kAlt)
this.modifierAlt = true;
else if (mod == kShift)
this.modifierShift = true;
else if (mod == kCtrl)
this.modifierCtrl = true;
else {
this.keyCodeModifier = kNone;
break;
}
}
}
} catch(e) {
this.keyCodeModifier = kNone;
}
break;
case "keyCode.up":
try {
this.keyCodeUp = this._branch.getIntPref("keyCode.up");
} catch(e) {
this.keyCodeUp = Ci.nsIDOMKeyEvent.DOM_VK_UP;
}
break;
case "keyCode.down":
try {
this.keyCodeDown = this._branch.getIntPref("keyCode.down");
} catch(e) {
this.keyCodeDown = Ci.nsIDOMKeyEvent.DOM_VK_DOWN;
}
break;
case "keyCode.left":
try {
this.keyCodeLeft = this._branch.getIntPref("keyCode.left");
} catch(e) {
this.keyCodeLeft = Ci.nsIDOMKeyEvent.DOM_VK_LEFT;
}
break;
case "keyCode.right":
try {
this.keyCodeRight = this._branch.getIntPref("keyCode.right");
} catch(e) {
this.keyCodeRight = Ci.nsIDOMKeyEvent.DOM_VK_RIGHT;
}
break;
}
},
}
PrefObserver.register();