InputHandlerDirectSwipePan.java

/**
 * Copyright (C) 2013- Iordan Iordanov
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 * USA.
 */


package com.undatech.opaque.input;

import android.graphics.PointF;
import android.view.MotionEvent;
import android.os.Vibrator;

import com.undatech.opaque.R;
import com.undatech.opaque.RemoteCanvas;
import com.undatech.opaque.RemoteCanvasActivity;

public class InputHandlerDirectSwipePan extends InputHandlerGeneric {
	static final String TAG = "InputHandlerDirectSwipePan";
	public static final String ID = "DirectSwipePan";
	
	public InputHandlerDirectSwipePan(RemoteCanvasActivity activity, RemoteCanvas canvas, Vibrator myVibrator) {
		super(activity, canvas, myVibrator);
	}

	/*
	 * (non-Javadoc)
	 * @see com.undatech.opaque.input.InputHandler#getDescription()
	 */
	@Override
	public String getDescription() {
		return canvas.getResources().getString(R.string.input_method_direct_swipe_pan_description);
	}

	/*
	 * (non-Javadoc)
	 * @see com.undatech.opaque.input.InputHandler#getId()
	 */
	@Override
	public String getId() {
		return ID;
	}

	/*
	 * (non-Javadoc)
	 * @see android.view.GestureDetector.SimpleOnGestureListener#onDown(android.view.MotionEvent)
	 */
	@Override
	public boolean onDown(MotionEvent e) {
		panRepeater.stop();
		return true;
	}

	/*
	 * (non-Javadoc)
	 * @see android.view.GestureDetector.SimpleOnGestureListener#onFling(android.view.MotionEvent, android.view.MotionEvent, float, float)
	 */
	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

		// TODO: Workaround for Android 4.2.
		boolean twoFingers = false;
		if (e1 != null)
			twoFingers = (e1.getPointerCount() > 1);
		if (e2 != null)
			twoFingers = twoFingers || (e2.getPointerCount() > 1);

		// onFling called while scaling/swiping gesture is in effect. We ignore the event and pretend it was
		// consumed. This prevents the mouse pointer from flailing around while we are scaling.
		// Also, if one releases one finger slightly earlier than the other when scaling, it causes Android 
		// to stick a spiteful onFling with a MASSIVE delta here. 
		// This would cause the mouse pointer to jump to another place suddenly.
		// Hence, we ignore onFing after scaling until we lift all pointers up.
		if (twoFingers||disregardNextOnFling||inSwiping||inScaling||scalingJustFinished) {
			return true;
		}

		activity.showKbdIcon();
		panRepeater.start(-velocityX, -velocityY);
		return true;
	}

	/*
	 * (non-Javadoc)
	 * @see android.view.GestureDetector.SimpleOnGestureListener#onScroll(android.view.MotionEvent, android.view.MotionEvent, float, float)
	 */
	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {

		if (!inScaling) {
			// onScroll called while swiping gesture is in effect. We ignore the event and pretend it was
			// consumed. This prevents the mouse pointer from flailing around while we are scaling.
			// Also, if one releases one finger slightly earlier than the other when scaling, it causes Android 
			// to stick a spiteful onScroll with a MASSIVE delta here. 
			// This would cause the mouse pointer to jump to another place suddenly.
			// Hence, we ignore onScroll after scaling until we lift all pointers up.
			boolean twoFingers = false;
			if (e1 != null)
				twoFingers = (e1.getPointerCount() > 1);
			if (e2 != null)
				twoFingers = twoFingers || (e2.getPointerCount() > 1);
	
			if (twoFingers||inSwiping||scalingJustFinished)
				return true;
		}

        if (!inScrolling) {
            inScrolling = true;
            distanceX = getSign(distanceX);
            distanceY = getSign(distanceY);
            distXQueue.clear();
            distYQueue.clear();
        }
        
        distXQueue.add(distanceX);
        distYQueue.add(distanceY);

        // Only after the first two events have arrived do we start using distanceX and Y
        // In order to effectively discard the last two events (which are typically unreliable
        // because of the finger lifting off).
        if (distXQueue.size() > 2) {
            distanceX = distXQueue.poll();
            distanceY = distYQueue.poll();
        } else {
            return true;
        }
       
		float scale = canvas.getZoomFactor();
		activity.showKbdIcon();
		canvas.relativePan((int)(distanceX*scale), (int)(distanceY*scale));
		return true;
	}
}