content: /*
   * Copyright (c) 2012 Jason Polites
   * 
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *     http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.polites;
  
  import android.graphics.PointF;
  
  
  /**
   * @author Jason Polites
   *
   */
  public class ZoomAnimation implements Animation {
  
  	private boolean firstFrame = true;
  	
  	private float touchX;
  	private float touchY;
  	
  	private float zoom;
  	
  	private float startX;
  	private float startY;
  	private float startScale;
  	
  	private float xDiff;
  	private float yDiff;
  	private float scaleDiff;
  	
  	private long animationLengthMS = 200;
  	private long totalTime = 0;
  	
  	private ZoomAnimationListener zoomAnimationListener;
  
  	/* (non-Javadoc)
  	 * @see com.polites.android.Animation#update(com.polites.android.GestureImageView, long)
  	 */
  	@Override
  	public boolean update(GestureImageView view, long time) {
  		if(firstFrame) {
  			firstFrame = false;
  			
  			startX = view.getImageX();
  			startY = view.getImageY();
  			startScale = view.getScale();
  			scaleDiff = (zoom * startScale) - startScale;
  			
  			if(scaleDiff > 0) {
  				// Calculate destination for midpoint
  				VectorF vector = new VectorF();
  				
  				// Set the touch point as start because we want to move the end				
  				vector.setStart(new PointF(touchX, touchY));
  				vector.setEnd(new PointF(startX, startY));				
  			
  				vector.calculateAngle();
  				
  				// Get the current length
  				float length = vector.calculateLength();
  				
  				// Multiply length by zoom to get the new length
  				vector.length = length*zoom;
  				
  				// Now deduce the new endpoint
  				vector.calculateEndPoint();
  				
  				xDiff = vector.end.x - startX;
  				yDiff = vector.end.y - startY;
  			}
  			else {
  				// Zoom out to center
  				xDiff = view.getCenterX() - startX;
  				yDiff = view.getCenterY() - startY;
  			}
  		}
  		
  		totalTime += time;
  		
  		float ratio = (float) totalTime / (float) animationLengthMS;
  		
  		if(ratio < 1) {
  			
  			if(ratio > 0) {
  				// we still have time left
  				float newScale = (ratio * scaleDiff) + startScale;
  				float newX = (ratio * xDiff) + startX;
  				float newY = (ratio * yDiff) + startY;
  				
  				if(zoomAnimationListener != null) {
  					zoomAnimationListener.onZoom(newScale, newX, newY);
  				}
  			}
  
  			return true;
  		}
  		else {
  			
  			float newScale = scaleDiff + startScale;
  			float newX = xDiff + startX;
  			float newY = yDiff + startY;
  
  			if(zoomAnimationListener != null) {
  				zoomAnimationListener.onZoom(newScale, newX, newY);
  				zoomAnimationListener.onComplete();
  			}
  			
  			return false;
  		}
  	}
  	
  	public void reset() {
  		firstFrame = true;
  		totalTime = 0;
  	}
  
  	public float getZoom() {
  		return zoom;
  	}
  	
  	public void setZoom(float zoom) {
  		this.zoom = zoom;
  	}
  	
  	public float getTouchX() {
  		return touchX;
  	}
  	
  	public void setTouchX(float touchX) {
  		this.touchX = touchX;
  	}
  	
  	public float getTouchY() {
  		return touchY;
  	}
  	
  	public void setTouchY(float touchY) {
  		this.touchY = touchY;
  	}
  	
  	public long getAnimationLengthMS() {
  		return animationLengthMS;
  	}
  	
  	public void setAnimationLengthMS(long animationLengthMS) {
  		this.animationLengthMS = animationLengthMS;
  	}
  	
  	public ZoomAnimationListener getZoomAnimationListener() {
  		return zoomAnimationListener;
  	}
  	
  	public void setZoomAnimationListener(ZoomAnimationListener zoomAnimationListener) {
  		this.zoomAnimationListener = zoomAnimationListener;
  	}
  }
  