gecko/browser/base/content/browser-textZoom.js

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/*
#ifdef 0
* ***** 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 Content Preferences (cpref).
*
* The Initial Developer of the Original Code is Mozilla.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Myk Melez <myk@mozilla.org>
*
* 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 *****
#endif
*/
// From nsMouseScrollEvent::kIsHorizontal
const MOUSE_SCROLL_IS_HORIZONTAL = 1 << 2;
// Not sure where this comes from. It's one of the possible values
// for the mousewheel.* preferences.
const MOUSE_SCROLL_TEXTSIZE = 3;
/**
* Controls the "text zoom" setting and its site-specific preferences.
*/
var TextZoom = {
//**************************************************************************//
// Name & Values
// The name of the setting. Identifies the setting in the prefs database.
name: "browser.content.text-zoom",
// The global value (if any) for the setting. Retrieved from the prefs
// database when this handler gets initialized, then updated as it changes.
// If there is no global value, then this should be undefined.
globalValue: undefined,
// From viewZoomOverlay.js
minValue: 1,
maxValue: 2000,
defaultValue: 100,
//**************************************************************************//
// Convenience Getters
__zoomManager: null,
get _zoomManager() {
if (!this.__zoomManager)
this.__zoomManager = ZoomManager.prototype.getInstance();
return this.__zoomManager;
},
// Content Pref Service
__cps: null,
get _cps() {
if (!this.__cps)
this.__cps = Cc["@mozilla.org/content-pref/service;1"].
getService(Ci.nsIContentPrefService);
return this.__cps;
},
// Pref Branch
__prefBranch: null,
get _prefBranch() {
if (!this.__prefBranch)
this.__prefBranch = Cc["@mozilla.org/preferences-service;1"].
getService(Ci.nsIPrefBranch);
return this.__prefBranch;
},
//**************************************************************************//
// nsISupports
// We can't use the Ci shortcut here because it isn't defined yet.
interfaces: [Components.interfaces.nsIDOMEventListener,
Components.interfaces.nsIContentPrefObserver,
Components.interfaces.nsISupports],
QueryInterface: function TextZoom_QueryInterface(aIID) {
if (!this.interfaces.some( function(v) { return aIID.equals(v) } ))
throw Cr.NS_ERROR_NO_INTERFACE;
return this;
},
//**************************************************************************//
// Initialization & Destruction
init: function TextZoom_init() {
// Listen for scrollwheel events so we can save scrollwheel-based changes.
window.addEventListener("DOMMouseScroll", this, false);
// Register ourselves with the service so we know when our pref changes.
this._cps.addObserver(this.name, this);
// Register ourselves with the sink so we know when the location changes.
var globalValue = ContentPrefSink.addObserver(this.name, this);
this.globalValue = this._ensureValid(globalValue);
// Set the initial value of the setting.
this._applyPrefToSetting();
},
destroy: function TextZoom_destroy() {
ContentPrefSink.removeObserver(this.name, this);
this._cps.removeObserver(this.name, this);
window.removeEventListener("DOMMouseScroll", this, false);
// Delete references to XPCOM components to make sure we don't leak them
// (although we haven't observed leakage in tests).
for (var i in this) {
try { this[i] = null }
// Ignore "setting a property that has only a getter" exceptions.
catch(ex) {}
}
},
//**************************************************************************//
// Event Handlers
// nsIDOMEventListener
handleEvent: function TextZoom_handleEvent(event) {
// The only events we handle are DOMMouseScroll events.
this._handleMouseScrolled(event);
},
_handleMouseScrolled: function TextZoom__handleMouseScrolled(event) {
// Construct the "mousewheel action" pref key corresponding to this event.
// Based on nsEventStateManager::GetBasePrefKeyForMouseWheel.
var pref = "mousewheel";
if (event.scrollFlags & MOUSE_SCROLL_IS_HORIZONTAL)
pref += ".horizscroll";
if (event.shiftKey)
pref += ".withshiftkey";
else if (event.ctrlKey)
pref += ".withcontrolkey";
else if (event.altKey)
pref += ".withaltkey";
else if (event.metaKey)
pref += ".withmetakey";
else
pref += ".withnokey";
pref += ".action";
// Don't do anything if this isn't a "change text size" scroll event.
if (this._getAppPref(pref, null) != MOUSE_SCROLL_TEXTSIZE)
return;
// XXX Lazily cache all the possible action prefs so we don't have to get
// them anew from the pref service for every scroll event? We'd have to
// make sure to observe them so we can update the cache when they change.
// We have to call _applySettingToPref in a timeout because we handle
// the event before the event state manager has a chance to apply the zoom
// during nsEventStateManager::PostHandleEvent.
window.setTimeout(function() { TextZoom._applySettingToPref() }, 0);
},
// nsIContentPrefObserver
onContentPrefSet: function TextZoom_onContentPrefSet(aGroup, aName, aValue) {
if (aGroup == this._cps.grouper.group(gBrowser.currentURI))
this._applyPrefToSetting(aValue);
else if (aGroup == null) {
this.globalValue = this._ensureValid(aValue);
// If the current page doesn't have a site-specific preference,
// then its zoom should be set to the new global preference now that
// the global preference has changed.
if (!this._cps.hasPref(gBrowser.currentURI, this.name))
this._applyPrefToSetting();
}
},
onContentPrefRemoved: function TextZoom_onContentPrefRemoved(aGroup, aName) {
if (aGroup == this._cps.grouper.group(gBrowser.currentURI))
this._applyPrefToSetting();
else if (aGroup == null) {
this.globalValue = undefined;
// If the current page doesn't have a site-specific preference,
// then its zoom should be set to the default preference now that
// the global preference has changed.
if (!this._cps.hasPref(gBrowser.currentURI, this.name))
this._applyPrefToSetting();
}
},
// ContentPrefSink observer
onLocationChanged: function TextZoom_onLocationChanged(aURI, aName, aValue) {
this._applyPrefToSetting(aValue);
},
//**************************************************************************//
// Setting & Pref Manipulation
reduce: function TextZoom_reduce() {
this._zoomManager.reduce();
this._applySettingToPref();
},
enlarge: function TextZoom_enlarge() {
this._zoomManager.enlarge();
this._applySettingToPref();
},
reset: function TextZoom_reset() {
if (typeof this.globalValue != "undefined")
this._zoomManager.textZoom = this.globalValue;
else
this._zoomManager.reset();
this._removePref();
},
/**
* Set the text zoom for the current tab.
*
* Per DocumentViewerImpl::SetTextZoom in nsDocumentViewer.cpp, it looks
* like we can set the zoom to its current value without significant impact
* on performance, as the setting is only applied if it differs from the
* current setting.
*
* And perhaps we should always set the zoom even if it were to incur
* a performance penalty, since SetTextZoom claims that child documents
* may have a different zoom under unusual circumstances, and it implies
* that those child zooms should get updated when the parent zoom gets set.
*
* So when we apply new zoom values to the browser, we simply set the zoom.
* We don't check first to see if the new value is the same as the current
* one.
**/
_applyPrefToSetting: function TextZoom__applyPrefToSetting(aValue) {
// Bug 375918 means this will sometimes throw, so we catch it
// and don't do anything in those cases.
try {
if (typeof aValue != "undefined")
this._zoomManager.textZoom = this._ensureValid(aValue);
else if (typeof this.globalValue != "undefined")
this._zoomManager.textZoom = this.globalValue;
else
this._zoomManager.reset();
}
catch(ex) {}
},
_applySettingToPref: function TextZoom__applySettingToPref() {
var textZoom = this._zoomManager.textZoom;
this._cps.setPref(gBrowser.currentURI, this.name, textZoom);
},
_removePref: function TextZoom__removePref() {
this._cps.removePref(gBrowser.currentURI, this.name);
},
//**************************************************************************//
// Utilities
_ensureValid: function TextZoom__ensureValid(aValue) {
if (isNaN(aValue))
return this.defaultValue;
if (aValue < this.minValue)
return this.minValue;
if (aValue > this.maxValue)
return this.maxValue;
return aValue;
},
/**
* Get a value from a pref or a default value if the pref doesn't exist.
*
* @param aPrefName
* @param aDefaultValue
* @returns the pref's value or the default (if it is missing)
*/
_getAppPref: function TextZoom__getAppPref(aPrefName, aDefaultValue) {
try {
switch (this._prefBranch.getPrefType(aPrefName)) {
case this._prefBranch.PREF_STRING:
return this._prefBranch.getCharPref(aPrefName);
case this._prefBranch.PREF_BOOL:
return this._prefBranch.getBoolPref(aPrefName);
case this._prefBranch.PREF_INT:
return this._prefBranch.getIntPref(aPrefName);
}
}
catch (ex) { /* return the default value */ }
return aDefaultValue;
}
};