mirror of
https://github.com/ionic-team/ionic-framework.git
synced 2025-11-07 06:57:02 +08:00
300 lines
8.7 KiB
JavaScript
300 lines
8.7 KiB
JavaScript
(function(ionic) {
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'use strict';
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ionic.views.ScrollView = function(opts) {
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var _this = this;
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// Extend the options with our defaults
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ionic.Utils.extend(opts, {
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decelerationRate: ionic.views.ScrollView.prototype.DECEL_RATE_NORMAL,
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dragThresholdY: 10,
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resistance: 2,
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scrollEventName: 'momentumScrolled',
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intertialEventInterval: 50,
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bounceTime: 600 //how long to take when bouncing back in a rubber band
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});
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ionic.Utils.extend(this, opts);
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this.el = opts.el;
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// Listen for drag and release events
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ionic.onGesture('drag', function(e) {
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_this._handleDrag(e);
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}, this.el);
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ionic.onGesture('release', function(e) {
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_this._handleEndDrag(e);
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}, this.el);
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ionic.on('webkitTransitionEnd', function(e) {
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_this._endTransition();
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});
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};
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ionic.views.ScrollView.prototype = {
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DECEL_RATE_NORMAL: 0.998,
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DECEL_RATE_FAST: 0.99,
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DECEL_RATE_SLOW: 0.996,
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_getMomentum: function (current, start, time, lowerMargin, wrapperSize) {
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var distance = current - start,
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speed = Math.abs(distance) / time,
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destination,
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duration,
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deceleration = 0.0006;
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// Calculate the final desination
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destination = current + ( speed * speed ) / ( 2 * deceleration ) * ( distance < 0 ? -1 : 1 );
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duration = speed / deceleration;
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// Check if the final destination needs to be rubber banded
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if ( destination < lowerMargin ) {
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// We have dragged too far down, snap back to the maximum
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destination = wrapperSize ? lowerMargin - ( wrapperSize / 2.5 * ( speed / 8 ) ) : lowerMargin;
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distance = Math.abs(destination - current);
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duration = distance / speed;
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} else if ( destination > 0 ) {
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// We have dragged too far up, snap back to 0
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destination = 0;//wrapperSize ? wrapperSize / 2.5 * ( speed / 8 ) : 0;
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distance = Math.abs(current) + destination;
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duration = distance / speed;
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}
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console.log('Momentum of time', time, speed, destination, duration);
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return {
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destination: Math.round(destination),
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duration: duration
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};
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},
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/**
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* Scroll to the given X and Y point, taking
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* the given amount of time, with the given
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* easing function defined as a CSS3 timing function.
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*
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* @param {float} the x position to scroll to (CURRENTLY NOT SUPPORTED!)
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* @param {float} the y position to scroll to
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* @param {float} the time to take scrolling to the new position
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* @param {easing} the animation function to use for easing
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*/
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scrollTo: function(x, y, time, easing) {
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var _this = this;
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easing = easing || 'cubic-bezier(0.1, 0.57, 0.1, 1)';
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var el = this.el;
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el.style.webkitTransitionTimingFunction = easing;
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el.style.webkitTransitionDuration = time;
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el.style.webkitTransform = 'translate3d(0,' + y + 'px, 0)';
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// Start triggering events as the element scrolls from inertia.
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// This is important because we need to receive scroll events
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// even after a "flick" and adjust, etc.
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this._momentumStepTimeout = setTimeout(function eventNotify() {
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var scrollTop = parseFloat(_this.el.style.webkitTransform.replace('translate3d(', '').split(',')[1]) || 0;
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ionic.trigger(_this.scrollEventName, {
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target: _this.el,
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scrollTop: -scrollTop
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});
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if(_this._isDragging) {
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_this._momentumStepTimeout = setTimeout(eventNotify, _this.inertialEventInterval);
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}
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}, this.inertialEventInterval)
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console.log('TRANSITION ADDED!');
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},
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_initDrag: function() {
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this._endTransition();
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this._isStopped = false;
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},
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_endTransition: function() {
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this._isDragging = false;
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this._drag = null;
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this.el.classList.remove('scroll-scrolling');
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console.log('REMOVING TRANSITION');
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this.el.style.webkitTransitionDuration = '0';
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clearTimeout(this._momentumStepTimeout)
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},
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/**
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* Initialize a drag by grabbing the content area to drag, and any other
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* info we might need for the dragging.
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*/
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_startDrag: function(e) {
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var offsetX, content;
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this._initDrag();
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var scrollTop = parseFloat(this.el.style.webkitTransform.replace('translate3d(', '').split(',')[1]) || 0;
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this._drag = {
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direction: 'v',
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y: scrollTop,
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pointY: e.gesture.touches[0].pageY,
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startY: scrollTop,
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resist: 1,
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startTime: Date.now()
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};
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},
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/**
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* Process the drag event to move the item to the left or right.
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*/
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_handleDrag: function(e) {
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var _this = this;
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var content;
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// The drag stopped already, don't process this one
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if(_this._isStopped) {
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_this._initDrag();
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return;
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}
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// We really aren't dragging
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if(!_this._drag) {
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_this._startDrag(e);
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}
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// Stop any default events during the drag
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e.preventDefault();
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var py = e.gesture.touches[0].pageY;
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var deltaY = py - _this._drag.pointY;
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console.log("Delta y", deltaY);
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_this._drag.pointY = py;
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// Check if we should start dragging. Check if we've dragged past the threshold.
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if(!_this._isDragging && (Math.abs(e.gesture.deltaY) > _this.dragThresholdY)) {
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_this._isDragging = true;
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}
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if(_this._isDragging) {
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var drag = _this._drag;
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window.requestAnimationFrame(function() {
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// We are dragging, grab the current content height
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// and the height of the parent container
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var totalHeight = _this.el.offsetHeight;
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var parentHeight = _this.el.parentNode.offsetHeight;
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var timestamp = Date.now();
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// Calculate the new Y point for the container
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var newY = drag.y + deltaY;
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// Check if the dragging is beyond the bottom or top
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if(newY > 0 || (-newY + parentHeight) > totalHeight) {
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// Rubber band
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newY = drag.y + deltaY / 3;//(-_this.resistance);
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}
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// Update the new translated Y point of the container
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_this.el.style.webkitTransform = 'translate3d(0,' + newY + 'px, 0)';
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drag.y = newY;
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// Check if we need to reset the drag initial states if we've
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// been dragging for a bit
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if(timestamp - drag.startTime > 300) {
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console.log('Resetting timer');
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drag.startTime = timestamp;
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drag.startY = drag.y;
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}
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ionic.trigger(_this.scrollEventName, {
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target: _this.el,
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scrollTop: -newY
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});
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});
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}
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},
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_handleEndDrag: function(e) {
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// We didn't have a drag, so just init and leave
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if(!this._drag) {
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this._initDrag();
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return;
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}
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// Set a flag in case we don't cleanup completely after the
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// drag animation so we can cleanup the next time a drag starts
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this._isStopped = true;
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// Animate to the finishing point
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this._animateToStop(e);
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},
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// Find the stopping point given the current velocity and acceleration rate, and
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// animate to that position
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_animateToStop: function(e) {
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var _this = this;
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if(this._drag.direction == 'v') {
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this._animateToStopVertical(e);
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} else {
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this._animateToStopHorizontal(e);
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}
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},
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_animateToStopHorizontal: function(e) {
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},
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_animateToStopVertical: function(e) {
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var _this = this;
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window.requestAnimationFrame(function() {
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var drag = _this._drag;
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// Calculate the viewport height and the height of the content
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var totalHeight = _this.el.offsetHeight;
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var parentHeight = _this.el.parentNode.offsetHeight;
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// Calculate how long we've been dragging for, with a max of 300ms
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var duration = Math.min(300, (Date.now()) - _this._drag.startTime);
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//var newX = Math.round(this.x),
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var newY = Math.round(drag.y);
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//distanceX = Math.abs(newX - this.startX),
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//var distanceY = Math.abs(newY - drag.startY);
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var momentum = _this._getMomentum(drag.y, drag.startY, duration, parentHeight - totalHeight, parentHeight);
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//var newX = momentumX.destination;
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newY = momentum.destination;
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var time = momentum.duration;
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if(drag.y > 0) {
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_this.scrollTo(0, 0, _this.bounceTime);
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return;
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} else if ((-drag.y + parentHeight) > totalHeight) {
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_this.scrollTo(0, totalHeight - parentHeight, _this.bounceTime);
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return;
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}
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var el = _this.el;
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// Turn on animation
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_this.scrollTo(0, newY, time);
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});
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}
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};
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})(ionic);
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