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Swipe gesture algorithm rewritten for better recognition and failing

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This commit is contained in:
Pavel fljot 2012-03-06 23:17:23 +02:00
parent 9edcd04878
commit 7cdec34be4
1 changed files with 58 additions and 34 deletions
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92
src/org/gestouch/gestures/SwipeGesture.as
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@ -6,7 +6,6 @@ package org.gestouch.gestures
import flash.display.InteractiveObject;
import flash.geom.Point;
import flash.system.Capabilities;
[Event(name="gestureSwipe", type="org.gestouch.events.SwipeGestureEvent")]
/**
@ -17,16 +16,19 @@ package org.gestouch.gestures
*/
public class SwipeGesture extends Gesture
{
public var slop:Number = Gesture.DEFAULT_SLOP;
public var numTouchesRequired:uint = 1;
public var velocityThreshold:Number = 0.1;
public var minVelocity:Number = 1.5;
public var minDistance:Number = Capabilities.screenDPI * 0.5;
public var minVelocity:Number = 0.8;
public var minOffset:Number = Gesture.DEFAULT_SLOP;
public var direction:uint = SwipeGestureDirection.ORTHOGONAL;
public var maxDirectionalOffset:Number = Gesture.DEFAULT_SLOP << 1;
protected var _offset:Point = new Point();
protected var _startTime:int;
protected var _noDirection:Boolean;
protected var _avrgVel:Point = new Point();
protected var _prevAvrgVel:Point = new Point();
protected var _decelerationCounter:uint = 0;
public function SwipeGesture(target:InteractiveObject = null)
@ -54,6 +56,7 @@ package org.gestouch.gestures
_startTime = 0;
_offset.x = 0;
_offset.y = 0;
_decelerationCounter = 0;
super.reset();
}
@ -66,7 +69,7 @@ package org.gestouch.gestures
// Protected methods
//
// --------------------------------------------------------------------------
override protected function onTouchBegin(touch:Touch):void
{
if (touchesCount > numTouchesRequired)
@ -84,6 +87,7 @@ package org.gestouch.gestures
if (touchesCount == numTouchesRequired)
{
updateLocation();
_avrgVel.x = _avrgVel.y = 0;
// cache direction condition for performance
_noDirection = (SwipeGestureDirection.ORTHOGONAL & direction) == 0;
@ -96,33 +100,46 @@ package org.gestouch.gestures
if (touchesCount < numTouchesRequired)
return;
var prevCentralPointX:Number = _centralPoint.x;
var prevCentralPointY:Number = _centralPoint.y;
updateCentralPoint();
_offset.x = _centralPoint.x - _location.x;
_offset.y = _centralPoint.y - _location.y;
var offsetLength:Number = _offset.length;
var timeDelta:int = touch.time - _startTime;
var vel:Number = offsetLength / timeDelta;
var absVel:Number = vel > 0 ? vel : -vel;//faster Math.abs()
if (offsetLength < Gesture.DEFAULT_SLOP)
if (offsetLength < slop)
{
// no need in processing - we're in the very beginning of movement
return;
}
else if (absVel < velocityThreshold)
// average velocity (total offset to total duration)
_prevAvrgVel.x = _avrgVel.x;
_prevAvrgVel.y = _avrgVel.y;
var absPrevAvrgVel:Number = _prevAvrgVel.length;
var totalTime:int = touch.time - _startTime;
_avrgVel.x = _offset.x / totalTime;
_avrgVel.y = _offset.y / totalTime;
var avrgVel:Number = _avrgVel.length;
if (avrgVel * 0.95 < absPrevAvrgVel)
{
_decelerationCounter++;
}
if (_decelerationCounter > 5 || avrgVel < 0.1)
{
setState(GestureState.FAILED);
return;
}
var velX:Number = _offset.x / timeDelta;
var velY:Number = _offset.y / timeDelta;
if (_noDirection)
{
if (absVel >= minVelocity || (minDistance != minDistance || offsetLength >= minDistance))
// We should quickly fail if we have noticable deceleration
// or first movement happend way later after touch
if (avrgVel >= minVelocity && (minOffset != minOffset || offsetLength >= minOffset))
{
if (setState(GestureState.RECOGNIZED) && hasEventListener(SwipeGestureEvent.GESTURE_SWIPE))
{
@ -134,28 +151,30 @@ package org.gestouch.gestures
}
else
{
var recentOffsetX:Number = _centralPoint.x - prevCentralPointX;
var recentOffsetY:Number = _centralPoint.y - prevCentralPointY;
//faster Math.abs()
var absVelX:Number = velX > 0 ? velX : -velX;
var absVelY:Number = velY > 0 ? velY : -velY;
var absOffsetX:Number = _offset.x > 0 ? _offset.x : -_offset.x;
var absOffsetY:Number = _offset.y > 0 ? _offset.y : -_offset.y;
var absVelX:Number = _avrgVel.x > 0 ? _avrgVel.x : -_avrgVel.x;
var absVelY:Number = _avrgVel.y > 0 ? _avrgVel.y : -_avrgVel.y;
if (absVelX > absVelY)
{
var absOffsetX:Number = _offset.x > 0 ? _offset.x : -_offset.x;
if ((SwipeGestureDirection.HORIZONTAL & direction) == 0)
{
// horizontal velocity is greater then vertical, but we're not interested in any horizontal direction
setState(GestureState.FAILED);
}
else if (velX < 0 && (direction & SwipeGestureDirection.LEFT) == 0)
else if (recentOffsetX < 0 && (direction & SwipeGestureDirection.LEFT) == 0 ||
recentOffsetX > 0 && (direction & SwipeGestureDirection.RIGHT) == 0 ||
Math.abs(_offset.y) > maxDirectionalOffset)
{
// movement in opposite direction
// or too much diagonally
setState(GestureState.FAILED);
}
else if (velX > 0 && (direction & SwipeGestureDirection.RIGHT) == 0)
{
setState(GestureState.FAILED);
}
else if (absVelX >= minVelocity || (minDistance != minDistance || absOffsetX >= minDistance))
else if (absVelX >= minVelocity && (minOffset != minOffset || absOffsetX >= minOffset))
{
if (setState(GestureState.RECOGNIZED) && hasEventListener(SwipeGestureEvent.GESTURE_SWIPE))
{
@ -167,20 +186,22 @@ package org.gestouch.gestures
}
else if (absVelY > absVelX)
{
var absOffsetY:Number = _offset.y > 0 ? _offset.y : -_offset.y;
if ((SwipeGestureDirection.VERTICAL & direction) == 0)
{
// horizontal velocity is greater then vertical, but we're not interested in any horizontal direction
setState(GestureState.FAILED);
}
else if (velY < 0 && (direction & SwipeGestureDirection.UP) == 0)
else if (recentOffsetY < 0 && (direction & SwipeGestureDirection.UP) == 0 ||
recentOffsetY > 0 && (direction & SwipeGestureDirection.DOWN) == 0 ||
Math.abs(_offset.x) > maxDirectionalOffset)
{
// movement in opposite direction
// or too much diagonally
setState(GestureState.FAILED);
}
else if (velY > 0 && (direction & SwipeGestureDirection.DOWN) == 0)
{
setState(GestureState.FAILED);
}
else if (absVelY >= minVelocity || (minDistance != minDistance || absOffsetY >= minDistance))
else if (absVelY >= minVelocity && (minOffset != minOffset || absOffsetY >= minOffset))
{
if (setState(GestureState.RECOGNIZED) && hasEventListener(SwipeGestureEvent.GESTURE_SWIPE))
{
@ -200,7 +221,10 @@ package org.gestouch.gestures
override protected function onTouchEnd(touch:Touch):void
{
setState(GestureState.FAILED);
if (touchesCount < numTouchesRequired)
{
setState(GestureState.FAILED);
}
}
}
}