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MouseSync.js
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MouseSync.js
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/* 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/.
*
* Owner: mark@famo.us
* @license MPL 2.0
* @copyright Famous Industries, Inc. 2015
*/
var EventHandler = require('../core/EventHandler');
var OptionsManager = require('../core/OptionsManager');
/**
* Handles piped in mouse drag events. Outputs an object with the position delta from last frame, position from start,
* current velocity averaged out over the velocitySampleLength (set via options), clientX, clientY, offsetX, and offsetY.
*
* Emits 'start', 'update' and 'end' events. Designed to be used either as a standalone MouseSync, or as part of a
* GenericSync.
*
* @class MouseSync
* @constructor
*
* @example
* var Surface = require('../core/Surface');
* var MouseSync = require('../inputs/MouseSync');
*
* var surface = new Surface({ size: [100, 100] });
* var mouseSync = new MouseSync();
* surface.pipe(mouseSync);
*
* mouseSync.on('start', function (e) { // react to start });
* mouseSync.on('update', function (e) { // react to update });
* mouseSync.on('end', function (e) { // react to end });
*
* @param [options] {Object} An object of the following configurable options.
* @param [options.clickThreshold] {Number} Absolute distance from click origin that will still trigger a click.
* @param [options.direction] {Number} Read from a particular axis. Valid options are: undefined, 0 or 1. 0 corresponds to x, and 1 to y. Default is undefined, which allows both x and y.
* @param [options.rails] {Boolean} Read from axis with the greatest differential.
* @param [options.velocitySampleLength] {Number} Number of previous frames to check velocity against.
* @param [options.propogate] {Boolean} Add a listener to document on mouseleave. This allows drag events to continue across the entire page.
*/
function MouseSync(options) {
this.options = Object.create(MouseSync.DEFAULT_OPTIONS);
this._optionsManager = new OptionsManager(this.options);
if (options) this.setOptions(options);
this._eventInput = new EventHandler();
this._eventOutput = new EventHandler();
EventHandler.setInputHandler(this, this._eventInput);
EventHandler.setOutputHandler(this, this._eventOutput);
this._eventInput.on('mousedown', _handleStart.bind(this));
this._eventInput.on('mousemove', _handleMove.bind(this));
this._eventInput.on('mouseup', _handleEnd.bind(this));
if (this.options.propogate) this._eventInput.on('mouseleave', _handleLeave.bind(this));
else this._eventInput.on('mouseleave', _handleEnd.bind(this));
if (this.options.clickThreshold) {
window.addEventListener('click', function(event) {
if (Math.sqrt(Math.pow(this._displacement[0], 2) + Math.pow(this._displacement[1], 2)) > this.options.clickThreshold) {
event.stopPropagation();
}
}.bind(this), true);
}
this._payload = {
delta : null,
position : null,
velocity : null,
clientX : 0,
clientY : 0,
offsetX : 0,
offsetY : 0
};
this._positionHistory = [];
this._position = null; // to be deprecated
this._prevCoord = undefined;
this._prevTime = undefined;
this._down = false;
this._moved = false;
this._displacement = [0,0];
this._documentActive = false;
}
MouseSync.DEFAULT_OPTIONS = {
clickThreshold: undefined,
direction: undefined,
rails: false,
scale: 1,
propogate: true, // events piped to document on mouseleave
velocitySampleLength: 10,
preventDefault: true
};
MouseSync.DIRECTION_X = 0;
MouseSync.DIRECTION_Y = 1;
var MINIMUM_TICK_TIME = 8;
/**
* Triggered by mousedown.
*
* @method _handleStart
* @private
*/
function _handleStart(event) {
var delta;
var velocity;
if (this.options.preventDefault) event.preventDefault(); // prevent drag
var x = event.clientX;
var y = event.clientY;
this._prevCoord = [x, y];
this._prevTime = Date.now();
this._down = true;
this._move = false;
if (this.options.direction !== undefined) {
this._position = 0;
delta = 0;
velocity = 0;
}
else {
this._position = [0, 0];
delta = [0, 0];
velocity = [0, 0];
}
if (this.options.clickThreshold) {
this._displacement = [0,0];
}
var payload = this._payload;
payload.delta = delta;
payload.position = this._position;
payload.velocity = velocity;
payload.clientX = x;
payload.clientY = y;
payload.offsetX = event.offsetX;
payload.offsetY = event.offsetY;
this._positionHistory.push({
position: payload.position.slice ? payload.position.slice(0) : payload.position,
time: this._prevTime
});
this._eventOutput.emit('start', payload);
this._documentActive = false;
}
/**
* Triggered by mousemove.
*
* @method _handleMove
* @private
*/
function _handleMove(event) {
if (!this._prevCoord) return;
var prevCoord = this._prevCoord;
var prevTime = this._prevTime;
var x = event.clientX;
var y = event.clientY;
var currTime = Date.now();
var diffX = x - prevCoord[0];
var diffY = y - prevCoord[1];
if (this.options.rails) {
if (Math.abs(diffX) > Math.abs(diffY)) diffY = 0;
else diffX = 0;
}
var diffTime = Math.max(currTime - this._positionHistory[0].time, MINIMUM_TICK_TIME); // minimum tick time
var scale = this.options.scale;
var nextVel;
var nextDelta;
if (this.options.direction === MouseSync.DIRECTION_X) {
nextDelta = scale * diffX;
this._position += nextDelta;
nextVel = scale * (this._position - this._positionHistory[0].position) / diffTime;
}
else if (this.options.direction === MouseSync.DIRECTION_Y) {
nextDelta = scale * diffY;
this._position += nextDelta;
nextVel = scale * (this._position - this._positionHistory[0].position) / diffTime;
}
else {
nextDelta = [scale * diffX, scale * diffY];
nextVel = [
scale * (this._position[0] - this._positionHistory[0].position[0]) / diffTime,
scale * (this._position[1] - this._positionHistory[0].position[1]) / diffTime
];
this._position[0] += nextDelta[0];
this._position[1] += nextDelta[1];
}
if (this.options.clickThreshold !== false) {
this._displacement[0] += diffX;
this._displacement[1] += diffY;
}
var payload = this._payload;
payload.delta = nextDelta;
payload.position = this._position;
payload.velocity = nextVel;
payload.clientX = x;
payload.clientY = y;
payload.offsetX = event.offsetX;
payload.offsetY = event.offsetY;
if (this._positionHistory.length === this.options.velocitySampleLength) {
this._positionHistory.shift();
}
this._positionHistory.push({
position: payload.position.slice ? payload.position.slice(0) : payload.position,
time: currTime
});
this._eventOutput.emit('update', payload);
this._prevCoord = [x, y];
this._prevTime = currTime;
this._move = true;
}
/**
* Triggered by mouseup on the element or document body if propagation is enabled, or
* mouseleave if propagation is off.
*
* @method _handleEnd
* @private
*/
function _handleEnd(event) {
if (!this._down) return;
this._eventOutput.emit('end', this._payload);
this._prevCoord = undefined;
this._prevTime = undefined;
this._down = false;
this._move = false;
this._positionHistory = [];
}
/**
* Switches the mousemove listener to the document body, if propagation is enabled.
* @method _handleLeave
* @private
*/
function _handleLeave(event) {
if (!this._down || !this._move) return;
if (!this._documentActive) {
var boundMove = _handleMove.bind(this);
var boundEnd = function(event) {
_handleEnd.call(this, event);
document.removeEventListener('mousemove', boundMove);
document.removeEventListener('mouseup', boundEnd);
}.bind(this, event);
document.addEventListener('mousemove', boundMove);
document.addEventListener('mouseup', boundEnd);
this._documentActive = true;
}
}
/**
* Return entire options dictionary, including defaults.
*
* @method getOptions
* @return {Object} configuration options
*/
MouseSync.prototype.getOptions = function getOptions() {
return this.options;
};
/**
* Set internal options, overriding any default options
*
* @method setOptions
*
* @param [options] {Object} default options overrides
* @param [options.direction] {Number} read from a particular axis
* @param [options.rails] {Boolean} read from axis with greatest differential
* @param [options.propogate] {Boolean} add listened to document on mouseleave
*/
MouseSync.prototype.setOptions = function setOptions(options) {
return this._optionsManager.setOptions(options);
};
module.exports = MouseSync;