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/* Copyright (c) 2006-2013 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the 2-clause BSD license.
* See license.txt in the OpenLayers distribution or repository for the
* full text of the license. */
/**
* @requires OpenLayers/BaseTypes/Class.js
* @requires OpenLayers/Animation.js
*/
OpenLayers.Kinetic = OpenLayers.Class({
/**
* Property: threshold
* In most cases changing the threshold isn't needed.
* In px/ms, default to 0.
*/
threshold: 0,
/**
* Property: deceleration
* {Float} the deseleration in px/ms², default to 0.0035.
*/
deceleration: 0.0035,
/**
* Property: nbPoints
* {Integer} the number of points we use to calculate the kinetic
* initial values.
*/
nbPoints: 100,
/**
* Property: delay
* {Float} time to consider to calculate the kinetic initial values.
* In ms, default to 200.
*/
delay: 200,
/**
* Property: points
* List of points use to calculate the kinetic initial values.
*/
points: undefined,
/**
* Property: timerId
* ID of the timer.
*/
timerId: undefined,
/**
* Constructor: OpenLayers.Kinetic
*
* Parameters:
* options - {Object}
*/
initialize: function(options) {
OpenLayers.Util.extend(this, options);
},
/**
* Method: begin
* Begins the dragging.
*/
begin: function() {
OpenLayers.Animation.stop(this.timerId);
this.timerId = undefined;
this.points = [];
},
/**
* Method: update
* Updates during the dragging.
*
* Parameters:
* xy - {<OpenLayers.Pixel>} The new position.
*/
update: function(xy) {
this.points.unshift({xy: xy, tick: new Date().getTime()});
if (this.points.length > this.nbPoints) {
this.points.pop();
}
},
/**
* Method: end
* Ends the dragging, start the kinetic.
*
* Parameters:
* xy - {<OpenLayers.Pixel>} The last position.
*
* Returns:
* {Object} An object with two properties: "speed", and "theta". The
* "speed" and "theta" values are to be passed to the move
* function when starting the animation.
*/
end: function(xy) {
var last, now = new Date().getTime();
for (var i = 0, l = this.points.length, point; i < l; i++) {
point = this.points[i];
if (now - point.tick > this.delay) {
break;
}
last = point;
}
if (!last) {
return;
}
var time = new Date().getTime() - last.tick;
var dist = Math.sqrt(Math.pow(xy.x - last.xy.x, 2) +
Math.pow(xy.y - last.xy.y, 2));
var speed = dist / time;
if (speed == 0 || speed < this.threshold) {
return;
}
var theta = Math.asin((xy.y - last.xy.y) / dist);
if (last.xy.x <= xy.x) {
theta = Math.PI - theta;
}
return {speed: speed, theta: theta};
},
/**
* Method: move
* Launch the kinetic move pan.
*
* Parameters:
* info - {Object} An object with two properties, "speed", and "theta".
* These values are those returned from the "end" call.
* callback - {Function} Function called on every step of the animation,
* receives x, y (values to pan), end (is the last point).
*/
move: function(info, callback) {
var v0 = info.speed;
var fx = Math.cos(info.theta);
var fy = -Math.sin(info.theta);
var initialTime = new Date().getTime();
var lastX = 0;
var lastY = 0;
var timerCallback = function() {
if (this.timerId == null) {
return;
}
var t = new Date().getTime() - initialTime;
var p = (-this.deceleration * Math.pow(t, 2)) / 2.0 + v0 * t;
var x = p * fx;
var y = p * fy;
var args = {};
args.end = false;
var v = -this.deceleration * t + v0;
if (v <= 0) {
OpenLayers.Animation.stop(this.timerId);
this.timerId = null;
args.end = true;
}
args.x = x - lastX;
args.y = y - lastY;
lastX = x;
lastY = y;
callback(args.x, args.y, args.end);
};
this.timerId = OpenLayers.Animation.start(
OpenLayers.Function.bind(timerCallback, this)
);
},
CLASS_NAME: "OpenLayers.Kinetic"
});
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