gecko-dev/browser/base/content/browser-gestureSupport.js

1121 lines
37 KiB
JavaScript

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
// Simple gestures support
//
// As per bug #412486, web content must not be allowed to receive any
// simple gesture events. Multi-touch gesture APIs are in their
// infancy and we do NOT want to be forced into supporting an API that
// will probably have to change in the future. (The current Mac OS X
// API is undocumented and was reverse-engineered.) Until support is
// implemented in the event dispatcher to keep these events as
// chrome-only, we must listen for the simple gesture events during
// the capturing phase and call stopPropagation on every event.
let gGestureSupport = {
_currentRotation: 0,
_lastRotateDelta: 0,
_rotateMomentumThreshold: .75,
/**
* Add or remove mouse gesture event listeners
*
* @param aAddListener
* True to add/init listeners and false to remove/uninit
*/
init: function GS_init(aAddListener) {
// Bug 863514 - Make gesture support work in electrolysis
if (gMultiProcessBrowser)
return;
const gestureEvents = ["SwipeGestureStart",
"SwipeGestureUpdate", "SwipeGestureEnd", "SwipeGesture",
"MagnifyGestureStart", "MagnifyGestureUpdate", "MagnifyGesture",
"RotateGestureStart", "RotateGestureUpdate", "RotateGesture",
"TapGesture", "PressTapGesture"];
let addRemove = aAddListener ? window.addEventListener :
window.removeEventListener;
gestureEvents.forEach(function (event) addRemove("Moz" + event, this, true),
this);
},
/**
* Dispatch events based on the type of mouse gesture event. For now, make
* sure to stop propagation of every gesture event so that web content cannot
* receive gesture events.
*
* @param aEvent
* The gesture event to handle
*/
handleEvent: function GS_handleEvent(aEvent) {
if (!Services.prefs.getBoolPref(
"dom.debug.propagate_gesture_events_through_content")) {
aEvent.stopPropagation();
}
// Create a preference object with some defaults
let def = function(aThreshold, aLatched)
({ threshold: aThreshold, latched: !!aLatched });
switch (aEvent.type) {
case "MozSwipeGestureStart":
aEvent.preventDefault();
this._setupSwipeGesture(aEvent);
break;
case "MozSwipeGestureUpdate":
aEvent.preventDefault();
this._doUpdate(aEvent);
break;
case "MozSwipeGestureEnd":
aEvent.preventDefault();
this._doEnd(aEvent);
break;
case "MozSwipeGesture":
aEvent.preventDefault();
this.onSwipe(aEvent);
break;
case "MozMagnifyGestureStart":
aEvent.preventDefault();
#ifdef XP_WIN
this._setupGesture(aEvent, "pinch", def(25, 0), "out", "in");
#else
this._setupGesture(aEvent, "pinch", def(150, 1), "out", "in");
#endif
break;
case "MozRotateGestureStart":
aEvent.preventDefault();
this._setupGesture(aEvent, "twist", def(25, 0), "right", "left");
break;
case "MozMagnifyGestureUpdate":
case "MozRotateGestureUpdate":
aEvent.preventDefault();
this._doUpdate(aEvent);
break;
case "MozTapGesture":
aEvent.preventDefault();
this._doAction(aEvent, ["tap"]);
break;
case "MozRotateGesture":
aEvent.preventDefault();
this._doAction(aEvent, ["twist", "end"]);
break;
/* case "MozPressTapGesture":
break; */
}
},
/**
* Called at the start of "pinch" and "twist" gestures to setup all of the
* information needed to process the gesture
*
* @param aEvent
* The continual motion start event to handle
* @param aGesture
* Name of the gesture to handle
* @param aPref
* Preference object with the names of preferences and defaults
* @param aInc
* Command to trigger for increasing motion (without gesture name)
* @param aDec
* Command to trigger for decreasing motion (without gesture name)
*/
_setupGesture: function GS__setupGesture(aEvent, aGesture, aPref, aInc, aDec) {
// Try to load user-set values from preferences
for (let [pref, def] in Iterator(aPref))
aPref[pref] = this._getPref(aGesture + "." + pref, def);
// Keep track of the total deltas and latching behavior
let offset = 0;
let latchDir = aEvent.delta > 0 ? 1 : -1;
let isLatched = false;
// Create the update function here to capture closure state
this._doUpdate = function GS__doUpdate(aEvent) {
// Update the offset with new event data
offset += aEvent.delta;
// Check if the cumulative deltas exceed the threshold
if (Math.abs(offset) > aPref["threshold"]) {
// Trigger the action if we don't care about latching; otherwise, make
// sure either we're not latched and going the same direction of the
// initial motion; or we're latched and going the opposite way
let sameDir = (latchDir ^ offset) >= 0;
if (!aPref["latched"] || (isLatched ^ sameDir)) {
this._doAction(aEvent, [aGesture, offset > 0 ? aInc : aDec]);
// We must be getting latched or leaving it, so just toggle
isLatched = !isLatched;
}
// Reset motion counter to prepare for more of the same gesture
offset = 0;
}
};
// The start event also contains deltas, so handle an update right away
this._doUpdate(aEvent);
},
/**
* Checks whether a swipe gesture event can navigate the browser history or
* not.
*
* @param aEvent
* The swipe gesture event.
* @return true if the swipe event may navigate the history, false othwerwise.
*/
_swipeNavigatesHistory: function GS__swipeNavigatesHistory(aEvent) {
return this._getCommand(aEvent, ["swipe", "left"])
== "Browser:BackOrBackDuplicate" &&
this._getCommand(aEvent, ["swipe", "right"])
== "Browser:ForwardOrForwardDuplicate";
},
/**
* Sets up the history swipe animations for a swipe gesture event, if enabled.
*
* @param aEvent
* The swipe gesture start event.
*/
_setupSwipeGesture: function GS__setupSwipeGesture(aEvent) {
if (!this._swipeNavigatesHistory(aEvent))
return;
let canGoBack = gHistorySwipeAnimation.canGoBack();
let canGoForward = gHistorySwipeAnimation.canGoForward();
let isLTR = gHistorySwipeAnimation.isLTR;
if (canGoBack)
aEvent.allowedDirections |= isLTR ? aEvent.DIRECTION_LEFT :
aEvent.DIRECTION_RIGHT;
if (canGoForward)
aEvent.allowedDirections |= isLTR ? aEvent.DIRECTION_RIGHT :
aEvent.DIRECTION_LEFT;
let isVerticalSwipe = false;
if (gHistorySwipeAnimation.active) {
if (aEvent.direction == aEvent.DIRECTION_UP) {
isVerticalSwipe = true;
// Force a synchronous scroll to the top of the page.
content.scrollTo(content.scrollX, 0);
}
else if (aEvent.direction == aEvent.DIRECTION_DOWN) {
isVerticalSwipe = true;
// Force a synchronous scroll to the bottom of the page.
content.scrollTo(content.scrollX, content.scrollMaxY);
}
}
gHistorySwipeAnimation.startAnimation(isVerticalSwipe);
this._doUpdate = function GS__doUpdate(aEvent) {
gHistorySwipeAnimation.updateAnimation(aEvent.delta);
};
this._doEnd = function GS__doEnd(aEvent) {
gHistorySwipeAnimation.swipeEndEventReceived();
this._doUpdate = function (aEvent) {};
this._doEnd = function (aEvent) {};
}
},
/**
* Generator producing the powerset of the input array where the first result
* is the complete set and the last result (before StopIteration) is empty.
*
* @param aArray
* Source array containing any number of elements
* @yield Array that is a subset of the input array from full set to empty
*/
_power: function GS__power(aArray) {
// Create a bitmask based on the length of the array
let num = 1 << aArray.length;
while (--num >= 0) {
// Only select array elements where the current bit is set
yield aArray.reduce(function (aPrev, aCurr, aIndex) {
if (num & 1 << aIndex)
aPrev.push(aCurr);
return aPrev;
}, []);
}
},
/**
* Determine what action to do for the gesture based on which keys are
* pressed and which commands are set, and execute the command.
*
* @param aEvent
* The original gesture event to convert into a fake click event
* @param aGesture
* Array of gesture name parts (to be joined by periods)
* @return Name of the executed command. Returns null if no command is
* found.
*/
_doAction: function GS__doAction(aEvent, aGesture) {
let command = this._getCommand(aEvent, aGesture);
return command && this._doCommand(aEvent, command);
},
/**
* Determine what action to do for the gesture based on which keys are
* pressed and which commands are set
*
* @param aEvent
* The original gesture event to convert into a fake click event
* @param aGesture
* Array of gesture name parts (to be joined by periods)
*/
_getCommand: function GS__getCommand(aEvent, aGesture) {
// Create an array of pressed keys in a fixed order so that a command for
// "meta" is preferred over "ctrl" when both buttons are pressed (and a
// command for both don't exist)
let keyCombos = [];
["shift", "alt", "ctrl", "meta"].forEach(function (key) {
if (aEvent[key + "Key"])
keyCombos.push(key);
});
// Try each combination of key presses in decreasing order for commands
for (let subCombo of this._power(keyCombos)) {
// Convert a gesture and pressed keys into the corresponding command
// action where the preference has the gesture before "shift" before
// "alt" before "ctrl" before "meta" all separated by periods
let command;
try {
command = this._getPref(aGesture.concat(subCombo).join("."));
} catch (e) {}
if (command)
return command;
}
return null;
},
/**
* Execute the specified command.
*
* @param aEvent
* The original gesture event to convert into a fake click event
* @param aCommand
* Name of the command found for the event's keys and gesture.
*/
_doCommand: function GS__doCommand(aEvent, aCommand) {
let node = document.getElementById(aCommand);
if (node) {
if (node.getAttribute("disabled") != "true") {
let cmdEvent = document.createEvent("xulcommandevent");
cmdEvent.initCommandEvent("command", true, true, window, 0,
aEvent.ctrlKey, aEvent.altKey,
aEvent.shiftKey, aEvent.metaKey, aEvent);
node.dispatchEvent(cmdEvent);
}
}
else {
goDoCommand(aCommand);
}
},
/**
* Handle continual motion events. This function will be set by
* _setupGesture or _setupSwipe.
*
* @param aEvent
* The continual motion update event to handle
*/
_doUpdate: function(aEvent) {},
/**
* Handle gesture end events. This function will be set by _setupSwipe.
*
* @param aEvent
* The gesture end event to handle
*/
_doEnd: function(aEvent) {},
/**
* Convert the swipe gesture into a browser action based on the direction.
*
* @param aEvent
* The swipe event to handle
*/
onSwipe: function GS_onSwipe(aEvent) {
// Figure out which one (and only one) direction was triggered
for (let dir of ["UP", "RIGHT", "DOWN", "LEFT"]) {
if (aEvent.direction == aEvent["DIRECTION_" + dir]) {
this._coordinateSwipeEventWithAnimation(aEvent, dir);
break;
}
}
},
/**
* Process a swipe event based on the given direction.
*
* @param aEvent
* The swipe event to handle
* @param aDir
* The direction for the swipe event
*/
processSwipeEvent: function GS_processSwipeEvent(aEvent, aDir) {
this._doAction(aEvent, ["swipe", aDir.toLowerCase()]);
},
/**
* Coordinates the swipe event with the swipe animation, if any.
* If an animation is currently running, the swipe event will be
* processed once the animation stops. This will guarantee a fluid
* motion of the animation.
*
* @param aEvent
* The swipe event to handle
* @param aDir
* The direction for the swipe event
*/
_coordinateSwipeEventWithAnimation:
function GS__coordinateSwipeEventWithAnimation(aEvent, aDir) {
if ((gHistorySwipeAnimation.isAnimationRunning()) &&
(aDir == "RIGHT" || aDir == "LEFT")) {
gHistorySwipeAnimation.processSwipeEvent(aEvent, aDir);
}
else {
this.processSwipeEvent(aEvent, aDir);
}
},
/**
* Get a gesture preference or use a default if it doesn't exist
*
* @param aPref
* Name of the preference to load under the gesture branch
* @param aDef
* Default value if the preference doesn't exist
*/
_getPref: function GS__getPref(aPref, aDef) {
// Preferences branch under which all gestures preferences are stored
const branch = "browser.gesture.";
try {
// Determine what type of data to load based on default value's type
let type = typeof aDef;
let getFunc = "get" + (type == "boolean" ? "Bool" :
type == "number" ? "Int" : "Char") + "Pref";
return gPrefService[getFunc](branch + aPref);
}
catch (e) {
return aDef;
}
},
/**
* Perform rotation for ImageDocuments
*
* @param aEvent
* The MozRotateGestureUpdate event triggering this call
*/
rotate: function(aEvent) {
if (!(content.document instanceof ImageDocument))
return;
let contentElement = content.document.body.firstElementChild;
if (!contentElement)
return;
// If we're currently snapping, cancel that snap
if (contentElement.classList.contains("completeRotation"))
this._clearCompleteRotation();
this.rotation = Math.round(this.rotation + aEvent.delta);
contentElement.style.transform = "rotate(" + this.rotation + "deg)";
this._lastRotateDelta = aEvent.delta;
},
/**
* Perform a rotation end for ImageDocuments
*/
rotateEnd: function() {
if (!(content.document instanceof ImageDocument))
return;
let contentElement = content.document.body.firstElementChild;
if (!contentElement)
return;
let transitionRotation = 0;
// The reason that 360 is allowed here is because when rotating between
// 315 and 360, setting rotate(0deg) will cause it to rotate the wrong
// direction around--spinning wildly.
if (this.rotation <= 45)
transitionRotation = 0;
else if (this.rotation > 45 && this.rotation <= 135)
transitionRotation = 90;
else if (this.rotation > 135 && this.rotation <= 225)
transitionRotation = 180;
else if (this.rotation > 225 && this.rotation <= 315)
transitionRotation = 270;
else
transitionRotation = 360;
// If we're going fast enough, and we didn't already snap ahead of rotation,
// then snap ahead of rotation to simulate momentum
if (this._lastRotateDelta > this._rotateMomentumThreshold &&
this.rotation > transitionRotation)
transitionRotation += 90;
else if (this._lastRotateDelta < -1 * this._rotateMomentumThreshold &&
this.rotation < transitionRotation)
transitionRotation -= 90;
// Only add the completeRotation class if it is is necessary
if (transitionRotation != this.rotation) {
contentElement.classList.add("completeRotation");
contentElement.addEventListener("transitionend", this._clearCompleteRotation);
}
contentElement.style.transform = "rotate(" + transitionRotation + "deg)";
this.rotation = transitionRotation;
},
/**
* Gets the current rotation for the ImageDocument
*/
get rotation() {
return this._currentRotation;
},
/**
* Sets the current rotation for the ImageDocument
*
* @param aVal
* The new value to take. Can be any value, but it will be bounded to
* 0 inclusive to 360 exclusive.
*/
set rotation(aVal) {
this._currentRotation = aVal % 360;
if (this._currentRotation < 0)
this._currentRotation += 360;
return this._currentRotation;
},
/**
* When the location/tab changes, need to reload the current rotation for the
* image
*/
restoreRotationState: function() {
// Bug 863514 - Make gesture support work in electrolysis
if (gMultiProcessBrowser)
return;
if (!(content.document instanceof ImageDocument))
return;
let contentElement = content.document.body.firstElementChild;
let transformValue = content.window.getComputedStyle(contentElement, null)
.transform;
if (transformValue == "none") {
this.rotation = 0;
return;
}
// transformValue is a rotation matrix--split it and do mathemagic to
// obtain the real rotation value
transformValue = transformValue.split("(")[1]
.split(")")[0]
.split(",");
this.rotation = Math.round(Math.atan2(transformValue[1], transformValue[0]) *
(180 / Math.PI));
},
/**
* Removes the transition rule by removing the completeRotation class
*/
_clearCompleteRotation: function() {
let contentElement = content.document &&
content.document instanceof ImageDocument &&
content.document.body &&
content.document.body.firstElementChild;
if (!contentElement)
return;
contentElement.classList.remove("completeRotation");
contentElement.removeEventListener("transitionend", this._clearCompleteRotation);
},
};
// History Swipe Animation Support (bug 678392)
let gHistorySwipeAnimation = {
active: false,
isLTR: false,
/**
* Initializes the support for history swipe animations, if it is supported
* by the platform/configuration.
*/
init: function HSA_init() {
if (!this._isSupported())
return;
this.active = false;
this.isLTR = document.documentElement.mozMatchesSelector(
":-moz-locale-dir(ltr)");
this._trackedSnapshots = [];
this._startingIndex = -1;
this._historyIndex = -1;
this._boxWidth = -1;
this._boxHeight = -1;
this._maxSnapshots = this._getMaxSnapshots();
this._lastSwipeDir = "";
this._isVerticalSwipe = false;
// We only want to activate history swipe animations if we store snapshots.
// If we don't store any, we handle horizontal swipes without animations.
if (this._maxSnapshots > 0) {
this.active = true;
gBrowser.addEventListener("pagehide", this, false);
gBrowser.addEventListener("pageshow", this, false);
gBrowser.addEventListener("popstate", this, false);
gBrowser.addEventListener("DOMModalDialogClosed", this, false);
gBrowser.tabContainer.addEventListener("TabClose", this, false);
}
},
/**
* Uninitializes the support for history swipe animations.
*/
uninit: function HSA_uninit() {
gBrowser.removeEventListener("pagehide", this, false);
gBrowser.removeEventListener("pageshow", this, false);
gBrowser.removeEventListener("popstate", this, false);
gBrowser.removeEventListener("DOMModalDialogClosed", this, false);
gBrowser.tabContainer.removeEventListener("TabClose", this, false);
this.active = false;
this.isLTR = false;
},
/**
* Starts the swipe animation and handles fast swiping (i.e. a swipe animation
* is already in progress when a new one is initiated).
*
* @param aIsVerticalSwipe
* Whether we're dealing with a vertical swipe or not.
*/
startAnimation: function HSA_startAnimation(aIsVerticalSwipe) {
this._isVerticalSwipe = aIsVerticalSwipe;
if (this.isAnimationRunning()) {
// If this is a horizontal scroll, or if this is a vertical scroll that
// was started while a horizontal scroll was still running, handle it as
// as a fast swipe. In the case of the latter scenario, this allows us to
// start the vertical animation without first loading the final page, or
// taking another snapshot. If vertical scrolls are initiated repeatedly
// without prior horizontal scroll we skip this and restart the animation
// from 0.
if (!this._isVerticalSwipe || this._lastSwipeDir != "") {
gBrowser.stop();
this._lastSwipeDir = "RELOAD"; // just ensure that != ""
this._canGoBack = this.canGoBack();
this._canGoForward = this.canGoForward();
this._handleFastSwiping();
}
}
else {
this._startingIndex = gBrowser.webNavigation.sessionHistory.index;
this._historyIndex = this._startingIndex;
this._canGoBack = this.canGoBack();
this._canGoForward = this.canGoForward();
if (this.active) {
this._takeSnapshot();
this._installPrevAndNextSnapshots();
this._addBoxes();
this._lastSwipeDir = "";
}
}
this.updateAnimation(0);
},
/**
* Stops the swipe animation.
*/
stopAnimation: function HSA_stopAnimation() {
gHistorySwipeAnimation._removeBoxes();
},
/**
* Updates the animation between two pages in history.
*
* @param aVal
* A floating point value that represents the progress of the
* swipe gesture.
*/
updateAnimation: function HSA_updateAnimation(aVal) {
if (!this.isAnimationRunning())
return;
// We use the following value to decrease the bounce effect when scrolling
// to the top or bottom of the page, or when swiping back/forward past the
// browsing history. This value was determined experimentally.
let dampValue = 4;
if (this._isVerticalSwipe) {
this._prevBox.collapsed = true;
this._nextBox.collapsed = true;
this._positionBox(this._curBox, -1 * aVal / dampValue);
}
else if ((aVal >= 0 && this.isLTR) ||
(aVal <= 0 && !this.isLTR)) {
let tempDampValue = 1;
if (this._canGoBack)
this._prevBox.collapsed = false;
else {
tempDampValue = dampValue;
this._prevBox.collapsed = true;
}
// The current page is pushed to the right (LTR) or left (RTL),
// the intention is to go back.
// If there is a page to go back to, it should show in the background.
this._positionBox(this._curBox, aVal / tempDampValue);
// The forward page should be pushed offscreen all the way to the right.
this._positionBox(this._nextBox, 1);
}
else {
if (aVal < -1)
aVal = -1; // Cap value to avoid sliding the page further than allowed.
// The intention is to go forward. If there is a page to go forward to,
// it should slide in from the right (LTR) or left (RTL).
// Otherwise, the current page should slide to the left (LTR) or
// right (RTL) and the backdrop should appear in the background.
// For the backdrop to be visible in that case, the previous page needs
// to be hidden (if it exists).
if (this._canGoForward) {
this._nextBox.collapsed = false;
let offset = this.isLTR ? 1 : -1;
this._positionBox(this._curBox, 0);
this._positionBox(this._nextBox, offset + aVal);
}
else {
this._prevBox.collapsed = true;
this._positionBox(this._curBox, aVal / dampValue);
}
}
},
/**
* Event handler for events relevant to the history swipe animation.
*
* @param aEvent
* An event to process.
*/
handleEvent: function HSA_handleEvent(aEvent) {
switch (aEvent.type) {
case "TabClose":
let browser = gBrowser.getBrowserForTab(aEvent.target);
this._removeTrackedSnapshot(-1, browser);
break;
case "DOMModalDialogClosed":
this.stopAnimation();
break;
case "pageshow":
case "popstate":
if (aEvent.target != gBrowser.selectedBrowser.contentDocument)
break;
this.stopAnimation();
this._historyIndex = gBrowser.webNavigation.sessionHistory.index;
break;
case "pagehide":
if (aEvent.target == gBrowser.selectedBrowser.contentDocument) {
// Take a snapshot of a page whenever it's about to be navigated away
// from.
this._takeSnapshot();
}
break;
}
},
/**
* Checks whether the history swipe animation is currently running or not.
*
* @return true if the animation is currently running, false otherwise.
*/
isAnimationRunning: function HSA_isAnimationRunning() {
return !!this._container;
},
/**
* Process a swipe event based on the given direction.
*
* @param aEvent
* The swipe event to handle
* @param aDir
* The direction for the swipe event
*/
processSwipeEvent: function HSA_processSwipeEvent(aEvent, aDir) {
if (aDir == "RIGHT")
this._historyIndex += this.isLTR ? 1 : -1;
else if (aDir == "LEFT")
this._historyIndex += this.isLTR ? -1 : 1;
else
return;
this._lastSwipeDir = aDir;
},
/**
* Checks if there is a page in the browser history to go back to.
*
* @return true if there is a previous page in history, false otherwise.
*/
canGoBack: function HSA_canGoBack() {
if (this.isAnimationRunning())
return this._doesIndexExistInHistory(this._historyIndex - 1);
return gBrowser.webNavigation.canGoBack;
},
/**
* Checks if there is a page in the browser history to go forward to.
*
* @return true if there is a next page in history, false otherwise.
*/
canGoForward: function HSA_canGoForward() {
if (this.isAnimationRunning())
return this._doesIndexExistInHistory(this._historyIndex + 1);
return gBrowser.webNavigation.canGoForward;
},
/**
* Used to notify the history swipe animation that the OS sent a swipe end
* event and that we should navigate to the page that the user swiped to, if
* any. This will also result in the animation overlay to be torn down.
*/
swipeEndEventReceived: function HSA_swipeEndEventReceived() {
if (this._lastSwipeDir != "" && this._historyIndex != this._startingIndex)
this._navigateToHistoryIndex();
else
this.stopAnimation();
},
/**
* Checks whether a particular index exists in the browser history or not.
*
* @param aIndex
* The index to check for availability for in the history.
* @return true if the index exists in the browser history, false otherwise.
*/
_doesIndexExistInHistory: function HSA__doesIndexExistInHistory(aIndex) {
try {
gBrowser.webNavigation.sessionHistory.getEntryAtIndex(aIndex, false);
}
catch(ex) {
return false;
}
return true;
},
/**
* Navigates to the index in history that is currently being tracked by
* |this|.
*/
_navigateToHistoryIndex: function HSA__navigateToHistoryIndex() {
if (this._doesIndexExistInHistory(this._historyIndex))
gBrowser.webNavigation.gotoIndex(this._historyIndex);
else
this.stopAnimation();
},
/**
* Checks to see if history swipe animations are supported by this
* platform/configuration.
*
* return true if supported, false otherwise.
*/
_isSupported: function HSA__isSupported() {
return window.matchMedia("(-moz-swipe-animation-enabled)").matches;
},
/**
* Handle fast swiping (i.e. a swipe animation is already in
* progress when a new one is initiated). This will swap out the snapshots
* used in the previous animation with the appropriate new ones.
*/
_handleFastSwiping: function HSA__handleFastSwiping() {
this._installCurrentPageSnapshot(null);
this._installPrevAndNextSnapshots();
},
/**
* Adds the boxes that contain the snapshots used during the swipe animation.
*/
_addBoxes: function HSA__addBoxes() {
let browserStack =
document.getAnonymousElementByAttribute(gBrowser.getNotificationBox(),
"class", "browserStack");
this._container = this._createElement("historySwipeAnimationContainer",
"stack");
browserStack.appendChild(this._container);
this._prevBox = this._createElement("historySwipeAnimationPreviousPage",
"box");
this._container.appendChild(this._prevBox);
this._curBox = this._createElement("historySwipeAnimationCurrentPage",
"box");
this._container.appendChild(this._curBox);
this._nextBox = this._createElement("historySwipeAnimationNextPage",
"box");
this._container.appendChild(this._nextBox);
// Cache width and height.
this._boxWidth = this._curBox.getBoundingClientRect().width;
this._boxHeight = this._curBox.getBoundingClientRect().height;
},
/**
* Removes the boxes.
*/
_removeBoxes: function HSA__removeBoxes() {
this._curBox = null;
this._prevBox = null;
this._nextBox = null;
if (this._container)
this._container.parentNode.removeChild(this._container);
this._container = null;
this._boxWidth = -1;
this._boxHeight = -1;
},
/**
* Creates an element with a given identifier and tag name.
*
* @param aID
* An identifier to create the element with.
* @param aTagName
* The name of the tag to create the element for.
* @return the newly created element.
*/
_createElement: function HSA__createElement(aID, aTagName) {
let XULNS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
let element = document.createElementNS(XULNS, aTagName);
element.id = aID;
return element;
},
/**
* Moves a given box to a given X coordinate position.
*
* @param aBox
* The box element to position.
* @param aPosition
* The position (in X coordinates) to move the box element to.
*/
_positionBox: function HSA__positionBox(aBox, aPosition) {
let transform = "";
if (this._isVerticalSwipe)
transform = "translateY(" + this._boxHeight * aPosition + "px)";
else
transform = "translateX(" + this._boxWidth * aPosition + "px)";
aBox.style.transform = transform;
},
/**
* Takes a snapshot of the page the browser is currently on.
*/
_takeSnapshot: function HSA__takeSnapshot() {
if ((this._maxSnapshots < 1) ||
(gBrowser.webNavigation.sessionHistory.index < 0))
return;
let browser = gBrowser.selectedBrowser;
let r = browser.getBoundingClientRect();
let canvas = document.createElementNS("http://www.w3.org/1999/xhtml",
"canvas");
canvas.mozOpaque = true;
canvas.width = r.width;
canvas.height = r.height;
let ctx = canvas.getContext("2d");
let zoom = browser.markupDocumentViewer.fullZoom;
ctx.scale(zoom, zoom);
ctx.drawWindow(browser.contentWindow, 0, 0, r.width, r.height, "white",
ctx.DRAWWINDOW_DO_NOT_FLUSH | ctx.DRAWWINDOW_DRAW_VIEW |
ctx.DRAWWINDOW_ASYNC_DECODE_IMAGES |
ctx.DRAWWINDOW_USE_WIDGET_LAYERS);
this._installCurrentPageSnapshot(canvas);
this._assignSnapshotToCurrentBrowser(canvas);
},
/**
* Retrieves the maximum number of snapshots that should be kept in memory.
* This limit is a global limit and is valid across all open tabs.
*/
_getMaxSnapshots: function HSA__getMaxSnapshots() {
return gPrefService.getIntPref("browser.snapshots.limit");
},
/**
* Adds a snapshot to the list and initiates the compression of said snapshot.
* Once the compression is completed, it will replace the uncompressed
* snapshot in the list.
*
* @param aCanvas
* The snapshot to add to the list and compress.
*/
_assignSnapshotToCurrentBrowser:
function HSA__assignSnapshotToCurrentBrowser(aCanvas) {
let browser = gBrowser.selectedBrowser;
let currIndex = browser.webNavigation.sessionHistory.index;
this._removeTrackedSnapshot(currIndex, browser);
this._addSnapshotRefToArray(currIndex, browser);
if (!("snapshots" in browser))
browser.snapshots = [];
let snapshots = browser.snapshots;
// Temporarily store the canvas as the compressed snapshot.
// This avoids a blank page if the user swipes quickly
// between pages before the compression could complete.
snapshots[currIndex] = aCanvas;
// Kick off snapshot compression.
aCanvas.toBlob(function(aBlob) {
snapshots[currIndex] = aBlob;
}, "image/png"
);
},
/**
* Removes a snapshot identified by the browser and index in the array of
* snapshots for that browser, if present. If no snapshot could be identified
* the method simply returns without taking any action. If aIndex is negative,
* all snapshots for a particular browser will be removed.
*
* @param aIndex
* The index in history of the new snapshot, or negative value if all
* snapshots for a browser should be removed.
* @param aBrowser
* The browser the new snapshot was taken in.
*/
_removeTrackedSnapshot: function HSA__removeTrackedSnapshot(aIndex, aBrowser) {
let arr = this._trackedSnapshots;
let requiresExactIndexMatch = aIndex >= 0;
for (let i = 0; i < arr.length; i++) {
if ((arr[i].browser == aBrowser) &&
(aIndex < 0 || aIndex == arr[i].index)) {
delete aBrowser.snapshots[arr[i].index];
arr.splice(i, 1);
if (requiresExactIndexMatch)
return; // Found and removed the only element.
i--; // Make sure to revisit the index that we just removed an
// element at.
}
}
},
/**
* Adds a new snapshot reference for a given index and browser to the array
* of references to tracked snapshots.
*
* @param aIndex
* The index in history of the new snapshot.
* @param aBrowser
* The browser the new snapshot was taken in.
*/
_addSnapshotRefToArray:
function HSA__addSnapshotRefToArray(aIndex, aBrowser) {
let id = { index: aIndex,
browser: aBrowser };
let arr = this._trackedSnapshots;
arr.unshift(id);
while (arr.length > this._maxSnapshots) {
let lastElem = arr[arr.length - 1];
delete lastElem.browser.snapshots[lastElem.index];
arr.splice(-1, 1);
}
},
/**
* Converts a compressed blob to an Image object. In some situations
* (especially during fast swiping) aBlob may still be a canvas, not a
* compressed blob. In this case, we simply return the canvas.
*
* @param aBlob
* The compressed blob to convert, or a canvas if a blob compression
* couldn't complete before this method was called.
* @return A new Image object representing the converted blob.
*/
_convertToImg: function HSA__convertToImg(aBlob) {
if (!aBlob)
return null;
// Return aBlob if it's still a canvas and not a compressed blob yet.
if (aBlob instanceof HTMLCanvasElement)
return aBlob;
let img = new Image();
let url = "";
try {
url = URL.createObjectURL(aBlob);
img.onload = function() {
URL.revokeObjectURL(url);
};
}
finally {
img.src = url;
return img;
}
},
/**
* Sets the snapshot of the current page to the snapshot passed as parameter,
* or to the one previously stored for the current index in history if the
* parameter is null.
*
* @param aCanvas
* The snapshot to set the current page to. If this parameter is null,
* the previously stored snapshot for this index (if any) will be used.
*/
_installCurrentPageSnapshot:
function HSA__installCurrentPageSnapshot(aCanvas) {
let currSnapshot = aCanvas;
if (!currSnapshot) {
let snapshots = gBrowser.selectedBrowser.snapshots || {};
let currIndex = this._historyIndex;
if (currIndex in snapshots)
currSnapshot = this._convertToImg(snapshots[currIndex]);
}
document.mozSetImageElement("historySwipeAnimationCurrentPageSnapshot",
currSnapshot);
},
/**
* Sets the snapshots of the previous and next pages to the snapshots
* previously stored for their respective indeces.
*/
_installPrevAndNextSnapshots:
function HSA__installPrevAndNextSnapshots() {
let snapshots = gBrowser.selectedBrowser.snapshots || [];
let currIndex = this._historyIndex;
let prevIndex = currIndex - 1;
let prevSnapshot = null;
if (prevIndex in snapshots)
prevSnapshot = this._convertToImg(snapshots[prevIndex]);
document.mozSetImageElement("historySwipeAnimationPreviousPageSnapshot",
prevSnapshot);
let nextIndex = currIndex + 1;
let nextSnapshot = null;
if (nextIndex in snapshots)
nextSnapshot = this._convertToImg(snapshots[nextIndex]);
document.mozSetImageElement("historySwipeAnimationNextPageSnapshot",
nextSnapshot);
},
};