aaac7fed
 liuqimichale
add
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/**
* Only implements needed gestures for mobile.
*/
import * as eventUtil from './event';
var GestureMgr = function () {
/**
* @private
* @type {Array.<Object>}
*/
this._track = [];
};
GestureMgr.prototype = {
constructor: GestureMgr,
recognize: function (event, target, root) {
this._doTrack(event, target, root);
return this._recognize(event);
},
clear: function () {
this._track.length = 0;
return this;
},
_doTrack: function (event, target, root) {
var touches = event.touches;
if (!touches) {
return;
}
var trackItem = {
points: [],
touches: [],
target: target,
event: event
};
for (var i = 0, len = touches.length; i < len; i++) {
var touch = touches[i];
var pos = eventUtil.clientToLocal(root, touch, {});
trackItem.points.push([pos.zrX, pos.zrY]);
trackItem.touches.push(touch);
}
this._track.push(trackItem);
},
_recognize: function (event) {
for (var eventName in recognizers) {
if (recognizers.hasOwnProperty(eventName)) {
var gestureInfo = recognizers[eventName](this._track, event);
if (gestureInfo) {
return gestureInfo;
}
}
}
}
};
function dist(pointPair) {
var dx = pointPair[1][0] - pointPair[0][0];
var dy = pointPair[1][1] - pointPair[0][1];
return Math.sqrt(dx * dx + dy * dy);
}
function center(pointPair) {
return [
(pointPair[0][0] + pointPair[1][0]) / 2,
(pointPair[0][1] + pointPair[1][1]) / 2
];
}
var recognizers = {
pinch: function (track, event) {
var trackLen = track.length;
if (!trackLen) {
return;
}
var pinchEnd = (track[trackLen - 1] || {}).points;
var pinchPre = (track[trackLen - 2] || {}).points || pinchEnd;
if (pinchPre
&& pinchPre.length > 1
&& pinchEnd
&& pinchEnd.length > 1
) {
var pinchScale = dist(pinchEnd) / dist(pinchPre);
!isFinite(pinchScale) && (pinchScale = 1);
event.pinchScale = pinchScale;
var pinchCenter = center(pinchEnd);
event.pinchX = pinchCenter[0];
event.pinchY = pinchCenter[1];
return {
type: 'pinch',
target: track[0].target,
event: event
};
}
}
// Only pinch currently.
};
export default GestureMgr;
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