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package com.almeros.android.multitouch;
import android.content.Context;
import android.util.DisplayMetrics;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
/**
* @author Almer Thie (code.almeros.com)
* Copyright (c) 2013, Almer Thie (code.almeros.com)
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*/
public abstract class TwoFingerGestureDetector extends BaseGestureDetector {
private final float mEdgeSlop;
private float mRightSlopEdge;
private float mBottomSlopEdge;
protected float mPrevFingerDiffX;
protected float mPrevFingerDiffY;
protected float mCurrFingerDiffX;
protected float mCurrFingerDiffY;
private float mCurrLen;
private float mPrevLen;
public TwoFingerGestureDetector(Context context) {
super(context);
ViewConfiguration config = ViewConfiguration.get(context);
mEdgeSlop = config.getScaledEdgeSlop();
}
@Override
protected abstract void handleStartProgressEvent(int actionCode, MotionEvent event);
@Override
protected abstract void handleInProgressEvent(int actionCode, MotionEvent event);
protected void updateStateByEvent(MotionEvent curr){
super.updateStateByEvent(curr);
final MotionEvent prev = mPrevEvent;
mCurrLen = -1;
mPrevLen = -1;
// Previous
final float px0 = prev.getX(0);
final float py0 = prev.getY(0);
final float px1 = prev.getX(1);
final float py1 = prev.getY(1);
final float pvx = px1 - px0;
final float pvy = py1 - py0;
mPrevFingerDiffX = pvx;
mPrevFingerDiffY = pvy;
// Current
final float cx0 = curr.getX(0);
final float cy0 = curr.getY(0);
final float cx1 = curr.getX(1);
final float cy1 = curr.getY(1);
final float cvx = cx1 - cx0;
final float cvy = cy1 - cy0;
mCurrFingerDiffX = cvx;
mCurrFingerDiffY = cvy;
}
/**
* Return the current distance between the two pointers forming the
* gesture in progress.
*
* @return Distance between pointers in pixels.
*/
public float getCurrentSpan() {
if (mCurrLen == -1) {
final float cvx = mCurrFingerDiffX;
final float cvy = mCurrFingerDiffY;
mCurrLen = (float)Math.sqrt(cvx*cvx + cvy*cvy);
}
return mCurrLen;
}
/**
* Return the previous distance between the two pointers forming the
* gesture in progress.
*
* @return Previous distance between pointers in pixels.
*/
public float getPreviousSpan() {
if (mPrevLen == -1) {
final float pvx = mPrevFingerDiffX;
final float pvy = mPrevFingerDiffY;
mPrevLen = (float)Math.sqrt(pvx*pvx + pvy*pvy);
}
return mPrevLen;
}
/**
* MotionEvent has no getRawX(int) method; simulate it pending future API approval.
* @param event
* @param pointerIndex
* @return Raw X value or 0
*/
protected static float getRawX(MotionEvent event, int pointerIndex) {
float offset = event.getX() - event.getRawX();
if(pointerIndex < event.getPointerCount()){
return event.getX(pointerIndex) + offset;
}
return 0f;
}
/**
* MotionEvent has no getRawY(int) method; simulate it pending future API approval.
* @param event
* @param pointerIndex
* @return Raw Y value or 0
*/
protected static float getRawY(MotionEvent event, int pointerIndex) {
float offset = event.getY() - event.getRawY();
if(pointerIndex < event.getPointerCount()){
return event.getY(pointerIndex) + offset;
}
return 0f;
}
/**
* Check if we have a sloppy gesture. Sloppy gestures can happen if the edge
* of the user's hand is touching the screen, for example.
*
* @param event MotionEvent
* @return {@code true} if is a sloppy gesture, {@code false} if not
*/
protected boolean isSloppyGesture(MotionEvent event){
// As orientation can change, query the metrics in touch down
DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();
mRightSlopEdge = metrics.widthPixels - mEdgeSlop;
mBottomSlopEdge = metrics.heightPixels - mEdgeSlop;
final float edgeSlop = mEdgeSlop;
final float rightSlop = mRightSlopEdge;
final float bottomSlop = mBottomSlopEdge;
final float x0 = event.getRawX();
final float y0 = event.getRawY();
final float x1 = getRawX(event, 1);
final float y1 = getRawY(event, 1);
boolean p0sloppy = x0 < edgeSlop || y0 < edgeSlop
|| x0 > rightSlop || y0 > bottomSlop;
boolean p1sloppy = x1 < edgeSlop || y1 < edgeSlop
|| x1 > rightSlop || y1 > bottomSlop;
if (p0sloppy && p1sloppy) {
return true;
} else if (p0sloppy) {
return true;
} else if (p1sloppy) {
return true;
}
return false;
}
}
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