Android Open Source - TouchImageView Touch Image View






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The source code is released under:

opyright (c) 2012 Michael Ortiz Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Softw...

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Java Source Code

/*
 * TouchImageView.java/*  w  ww.  j a  v a2 s  .com*/
 * By: Michael Ortiz
 * Updated By: Patrick Lackemacher
 * Updated By: Babay88
 * Updated By: @ipsilondev
 * Updated By: hank-cp
 * Updated By: singpolyma
 * -------------------
 * Extends Android ImageView to include pinch zooming, panning, fling and double tap zoom.
 */

package com.ortiz.touch;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Build;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.ImageView;
import android.widget.OverScroller;
import android.widget.Scroller;

public class TouchImageView extends ImageView {
  
  private static final String DEBUG = "DEBUG";
  
  //
  // SuperMin and SuperMax multipliers. Determine how much the image can be
  // zoomed below or above the zoom boundaries, before animating back to the
  // min/max zoom boundary.
  //
  private static final float SUPER_MIN_MULTIPLIER = .75f;
  private static final float SUPER_MAX_MULTIPLIER = 1.25f;

    //
    // Scale of image ranges from minScale to maxScale, where minScale == 1
    // when the image is stretched to fit view.
    //
    private float normalizedScale;
    
    //
    // Matrix applied to image. MSCALE_X and MSCALE_Y should always be equal.
    // MTRANS_X and MTRANS_Y are the other values used. prevMatrix is the matrix
    // saved prior to the screen rotating.
    //
  private Matrix matrix, prevMatrix;

    private static enum State { NONE, DRAG, ZOOM, FLING, ANIMATE_ZOOM };
    private State state;

    private float minScale;
    private float maxScale;
    private float superMinScale;
    private float superMaxScale;
    private float[] m;
    
    private Context context;
    private Fling fling;
    
    private ScaleType mScaleType;
    
    private boolean imageRenderedAtLeastOnce;
    private boolean onDrawReady;
    
    private ZoomVariables delayedZoomVariables;

    //
    // Size of view and previous view size (ie before rotation)
    //
    private int viewWidth, viewHeight, prevViewWidth, prevViewHeight;
    
    //
    // Size of image when it is stretched to fit view. Before and After rotation.
    //
    private float matchViewWidth, matchViewHeight, prevMatchViewWidth, prevMatchViewHeight;
    
    private ScaleGestureDetector mScaleDetector;
    private GestureDetector mGestureDetector;
    private GestureDetector.OnDoubleTapListener doubleTapListener = null;
    private OnTouchListener userTouchListener = null;
    private OnTouchImageViewListener touchImageViewListener = null;

    public TouchImageView(Context context) {
        super(context);
        sharedConstructing(context);
    }

    public TouchImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
        sharedConstructing(context);
    }
    
    public TouchImageView(Context context, AttributeSet attrs, int defStyle) {
      super(context, attrs, defStyle);
      sharedConstructing(context);
    }
    
    private void sharedConstructing(Context context) {
        super.setClickable(true);
        this.context = context;
        mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
        mGestureDetector = new GestureDetector(context, new GestureListener());
        matrix = new Matrix();
        prevMatrix = new Matrix();
        m = new float[9];
        normalizedScale = 1;
        if (mScaleType == null) {
          mScaleType = ScaleType.FIT_CENTER;
        }
        minScale = 1;
        maxScale = 3;
        superMinScale = SUPER_MIN_MULTIPLIER * minScale;
        superMaxScale = SUPER_MAX_MULTIPLIER * maxScale;
        setImageMatrix(matrix);
        setScaleType(ScaleType.MATRIX);
        setState(State.NONE);
        onDrawReady = false;
        super.setOnTouchListener(new PrivateOnTouchListener());
    }

    @Override
    public void setOnTouchListener(View.OnTouchListener l) {
        userTouchListener = l;
    }
    
    public void setOnTouchImageViewListener(OnTouchImageViewListener l) {
      touchImageViewListener = l;
    }

    public void setOnDoubleTapListener(GestureDetector.OnDoubleTapListener l) {
        doubleTapListener = l;
    }

    @Override
    public void setImageResource(int resId) {
      super.setImageResource(resId);
      savePreviousImageValues();
      fitImageToView();
    }
    
    @Override
    public void setImageBitmap(Bitmap bm) {
      super.setImageBitmap(bm);
      savePreviousImageValues();
      fitImageToView();
    }
    
    @Override
    public void setImageDrawable(Drawable drawable) {
      super.setImageDrawable(drawable);
      savePreviousImageValues();
      fitImageToView();
    }
    
    @Override
    public void setImageURI(Uri uri) {
      super.setImageURI(uri);
      savePreviousImageValues();
      fitImageToView();
    }
    
    @Override
    public void setScaleType(ScaleType type) {
      if (type == ScaleType.FIT_START || type == ScaleType.FIT_END) {
        throw new UnsupportedOperationException("TouchImageView does not support FIT_START or FIT_END");
      }
      if (type == ScaleType.MATRIX) {
        super.setScaleType(ScaleType.MATRIX);
        
      } else {
        mScaleType = type;
        if (onDrawReady) {
          //
          // If the image is already rendered, scaleType has been called programmatically
          // and the TouchImageView should be updated with the new scaleType.
          //
          setZoom(this);
        }
      }
    }
    
    @Override
    public ScaleType getScaleType() {
      return mScaleType;
    }
    
    /**
     * Returns false if image is in initial, unzoomed state. False, otherwise.
     * @return true if image is zoomed
     */
    public boolean isZoomed() {
      return normalizedScale != 1;
    }
    
    /**
     * Return a Rect representing the zoomed image.
     * @return rect representing zoomed image
     */
    public RectF getZoomedRect() {
      if (mScaleType == ScaleType.FIT_XY) {
        throw new UnsupportedOperationException("getZoomedRect() not supported with FIT_XY");
      }
      PointF topLeft = transformCoordTouchToBitmap(0, 0, true);
      PointF bottomRight = transformCoordTouchToBitmap(viewWidth, viewHeight, true);
      
      float w = getDrawable().getIntrinsicWidth();
      float h = getDrawable().getIntrinsicHeight();
      return new RectF(topLeft.x / w, topLeft.y / h, bottomRight.x / w, bottomRight.y / h);
    }
    
    /**
     * Save the current matrix and view dimensions
     * in the prevMatrix and prevView variables.
     */
    private void savePreviousImageValues() {
      if (matrix != null && viewHeight != 0 && viewWidth != 0) {
        matrix.getValues(m);
        prevMatrix.setValues(m);
        prevMatchViewHeight = matchViewHeight;
          prevMatchViewWidth = matchViewWidth;
          prevViewHeight = viewHeight;
          prevViewWidth = viewWidth;
      }
    }
    
    @Override
    public Parcelable onSaveInstanceState() {
      Bundle bundle = new Bundle();
      bundle.putParcelable("instanceState", super.onSaveInstanceState());
      bundle.putFloat("saveScale", normalizedScale);
      bundle.putFloat("matchViewHeight", matchViewHeight);
      bundle.putFloat("matchViewWidth", matchViewWidth);
      bundle.putInt("viewWidth", viewWidth);
      bundle.putInt("viewHeight", viewHeight);
      matrix.getValues(m);
      bundle.putFloatArray("matrix", m);
      bundle.putBoolean("imageRendered", imageRenderedAtLeastOnce);
      return bundle;
    }
    
    @Override
    public void onRestoreInstanceState(Parcelable state) {
        if (state instanceof Bundle) {
          Bundle bundle = (Bundle) state;
          normalizedScale = bundle.getFloat("saveScale");
          m = bundle.getFloatArray("matrix");
          prevMatrix.setValues(m);
          prevMatchViewHeight = bundle.getFloat("matchViewHeight");
          prevMatchViewWidth = bundle.getFloat("matchViewWidth");
          prevViewHeight = bundle.getInt("viewHeight");
          prevViewWidth = bundle.getInt("viewWidth");
          imageRenderedAtLeastOnce = bundle.getBoolean("imageRendered");
          super.onRestoreInstanceState(bundle.getParcelable("instanceState"));
          return;
        }

        super.onRestoreInstanceState(state);
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
      onDrawReady = true;
      imageRenderedAtLeastOnce = true;
      if (delayedZoomVariables != null) {
        setZoom(delayedZoomVariables.scale, delayedZoomVariables.focusX, delayedZoomVariables.focusY, delayedZoomVariables.scaleType);
        delayedZoomVariables = null;
      }
      super.onDraw(canvas);
    }
    
    @Override
    public void onConfigurationChanged(Configuration newConfig) {
      super.onConfigurationChanged(newConfig);
      savePreviousImageValues();
    }
    
    /**
     * Get the max zoom multiplier.
     * @return max zoom multiplier.
     */
    public float getMaxZoom() {
      return maxScale;
    }

    /**
     * Set the max zoom multiplier. Default value: 3.
     * @param max max zoom multiplier.
     */
    public void setMaxZoom(float max) {
        maxScale = max;
        superMaxScale = SUPER_MAX_MULTIPLIER * maxScale;
    }
    
    /**
     * Get the min zoom multiplier.
     * @return min zoom multiplier.
     */
    public float getMinZoom() {
      return minScale;
    }
    
    /**
     * Get the current zoom. This is the zoom relative to the initial
     * scale, not the original resource.
     * @return current zoom multiplier.
     */
    public float getCurrentZoom() {
      return normalizedScale;
    }
    
    /**
     * Set the min zoom multiplier. Default value: 1.
     * @param min min zoom multiplier.
     */
    public void setMinZoom(float min) {
      minScale = min;
      superMinScale = SUPER_MIN_MULTIPLIER * minScale;
    }
    
    /**
     * Reset zoom and translation to initial state.
     */
    public void resetZoom() {
      normalizedScale = 1;
      fitImageToView();
    }
    
    /**
     * Set zoom to the specified scale. Image will be centered by default.
     * @param scale
     */
    public void setZoom(float scale) {
      setZoom(scale, 0.5f, 0.5f);
    }
    
    /**
     * Set zoom to the specified scale. Image will be centered around the point
     * (focusX, focusY). These floats range from 0 to 1 and denote the focus point
     * as a fraction from the left and top of the view. For example, the top left 
     * corner of the image would be (0, 0). And the bottom right corner would be (1, 1).
     * @param scale
     * @param focusX
     * @param focusY
     */
    public void setZoom(float scale, float focusX, float focusY) {
      setZoom(scale, focusX, focusY, mScaleType);
    }
    
    /**
     * Set zoom to the specified scale. Image will be centered around the point
     * (focusX, focusY). These floats range from 0 to 1 and denote the focus point
     * as a fraction from the left and top of the view. For example, the top left 
     * corner of the image would be (0, 0). And the bottom right corner would be (1, 1).
     * @param scale
     * @param focusX
     * @param focusY
     * @param scaleType
     */
    public void setZoom(float scale, float focusX, float focusY, ScaleType scaleType) {
      //
      // setZoom can be called before the image is on the screen, but at this point, 
      // image and view sizes have not yet been calculated in onMeasure. Thus, we should
      // delay calling setZoom until the view has been measured.
      //
      if (!onDrawReady) {
        delayedZoomVariables = new ZoomVariables(scale, focusX, focusY, scaleType);
        return;
      }
      
      if (scaleType != mScaleType) {
        setScaleType(scaleType);
      }
      resetZoom();
      scaleImage(scale, viewWidth / 2, viewHeight / 2, true);
      matrix.getValues(m);
      m[Matrix.MTRANS_X] = -((focusX * getImageWidth()) - (viewWidth * 0.5f));
      m[Matrix.MTRANS_Y] = -((focusY * getImageHeight()) - (viewHeight * 0.5f));
      matrix.setValues(m);
      fixTrans();
      setImageMatrix(matrix);
    }
    
    /**
     * Set zoom parameters equal to another TouchImageView. Including scale, position,
     * and ScaleType.
     * @param TouchImageView
     */
    public void setZoom(TouchImageView img) {
      PointF center = img.getScrollPosition();
      setZoom(img.getCurrentZoom(), center.x, center.y, img.getScaleType());
    }
    
    /**
     * Return the point at the center of the zoomed image. The PointF coordinates range
     * in value between 0 and 1 and the focus point is denoted as a fraction from the left 
     * and top of the view. For example, the top left corner of the image would be (0, 0). 
     * And the bottom right corner would be (1, 1).
     * @return PointF representing the scroll position of the zoomed image.
     */
    public PointF getScrollPosition() {
      Drawable drawable = getDrawable();
      if (drawable == null) {
        return null;
      }
      int drawableWidth = drawable.getIntrinsicWidth();
        int drawableHeight = drawable.getIntrinsicHeight();
        
        PointF point = transformCoordTouchToBitmap(viewWidth / 2, viewHeight / 2, true);
        point.x /= drawableWidth;
        point.y /= drawableHeight;
        return point;
    }
    
    /**
     * Set the focus point of the zoomed image. The focus points are denoted as a fraction from the
     * left and top of the view. The focus points can range in value between 0 and 1. 
     * @param focusX
     * @param focusY
     */
    public void setScrollPosition(float focusX, float focusY) {
      setZoom(normalizedScale, focusX, focusY);
    }
    
    /**
     * Performs boundary checking and fixes the image matrix if it 
     * is out of bounds.
     */
    private void fixTrans() {
        matrix.getValues(m);
        float transX = m[Matrix.MTRANS_X];
        float transY = m[Matrix.MTRANS_Y];
        
        float fixTransX = getFixTrans(transX, viewWidth, getImageWidth());
        float fixTransY = getFixTrans(transY, viewHeight, getImageHeight());
        
        if (fixTransX != 0 || fixTransY != 0) {
            matrix.postTranslate(fixTransX, fixTransY);
        }
    }
    
    /**
     * When transitioning from zooming from focus to zoom from center (or vice versa)
     * the image can become unaligned within the view. This is apparent when zooming
     * quickly. When the content size is less than the view size, the content will often
     * be centered incorrectly within the view. fixScaleTrans first calls fixTrans() and 
     * then makes sure the image is centered correctly within the view.
     */
    private void fixScaleTrans() {
      fixTrans();
      matrix.getValues(m);
      if (getImageWidth() < viewWidth) {
        m[Matrix.MTRANS_X] = (viewWidth - getImageWidth()) / 2;
      }
      
      if (getImageHeight() < viewHeight) {
        m[Matrix.MTRANS_Y] = (viewHeight - getImageHeight()) / 2;
      }
      matrix.setValues(m);
    }

    private float getFixTrans(float trans, float viewSize, float contentSize) {
        float minTrans, maxTrans;

        if (contentSize <= viewSize) {
            minTrans = 0;
            maxTrans = viewSize - contentSize;
            
        } else {
            minTrans = viewSize - contentSize;
            maxTrans = 0;
        }

        if (trans < minTrans)
            return -trans + minTrans;
        if (trans > maxTrans)
            return -trans + maxTrans;
        return 0;
    }
    
    private float getFixDragTrans(float delta, float viewSize, float contentSize) {
        if (contentSize <= viewSize) {
            return 0;
        }
        return delta;
    }
    
    private float getImageWidth() {
      return matchViewWidth * normalizedScale;
    }
    
    private float getImageHeight() {
      return matchViewHeight * normalizedScale;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        Drawable drawable = getDrawable();
        if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0) {
          setMeasuredDimension(0, 0);
          return;
        }
        
        int drawableWidth = drawable.getIntrinsicWidth();
        int drawableHeight = drawable.getIntrinsicHeight();
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        viewWidth = setViewSize(widthMode, widthSize, drawableWidth);
        viewHeight = setViewSize(heightMode, heightSize, drawableHeight);
        
        //
        // Set view dimensions
        //
        setMeasuredDimension(viewWidth, viewHeight);
        
        //
        // Fit content within view
        //
        fitImageToView();
    }
    
    /**
     * If the normalizedScale is equal to 1, then the image is made to fit the screen. Otherwise,
     * it is made to fit the screen according to the dimensions of the previous image matrix. This
     * allows the image to maintain its zoom after rotation.
     */
    private void fitImageToView() {
      Drawable drawable = getDrawable();
        if (drawable == null || drawable.getIntrinsicWidth() == 0 || drawable.getIntrinsicHeight() == 0) {
          return;
        }
        if (matrix == null || prevMatrix == null) {
          return;
        }
        
        int drawableWidth = drawable.getIntrinsicWidth();
        int drawableHeight = drawable.getIntrinsicHeight();
      
      //
      // Scale image for view
      //
        float scaleX = (float) viewWidth / drawableWidth;
        float scaleY = (float) viewHeight / drawableHeight;
        
        switch (mScaleType) {
        case CENTER:
          scaleX = scaleY = 1;
          break;
          
        case CENTER_CROP:
          scaleX = scaleY = Math.max(scaleX, scaleY);
          break;
          
        case CENTER_INSIDE:
          scaleX = scaleY = Math.min(1, Math.min(scaleX, scaleY));
          
        case FIT_CENTER:
          scaleX = scaleY = Math.min(scaleX, scaleY);
          break;
          
        case FIT_XY:
          break;
          
      default:
        //
        // FIT_START and FIT_END not supported
        //
        throw new UnsupportedOperationException("TouchImageView does not support FIT_START or FIT_END");
          
        }

        //
        // Center the image
        //
        float redundantXSpace = viewWidth - (scaleX * drawableWidth);
        float redundantYSpace = viewHeight - (scaleY * drawableHeight);
        matchViewWidth = viewWidth - redundantXSpace;
        matchViewHeight = viewHeight - redundantYSpace;
        if (!isZoomed() && !imageRenderedAtLeastOnce) {
          //
          // Stretch and center image to fit view
          //
          matrix.setScale(scaleX, scaleY);
          matrix.postTranslate(redundantXSpace / 2, redundantYSpace / 2);
          normalizedScale = 1;
          
        } else {
          //
          // These values should never be 0 or we will set viewWidth and viewHeight
          // to NaN in translateMatrixAfterRotate. To avoid this, call savePreviousImageValues
          // to set them equal to the current values.
          //
          if (prevMatchViewWidth == 0 || prevMatchViewHeight == 0) {
            savePreviousImageValues();
          }
          
          prevMatrix.getValues(m);
          
          //
          // Rescale Matrix after rotation
          //
          m[Matrix.MSCALE_X] = matchViewWidth / drawableWidth * normalizedScale;
          m[Matrix.MSCALE_Y] = matchViewHeight / drawableHeight * normalizedScale;
          
          //
          // TransX and TransY from previous matrix
          //
            float transX = m[Matrix.MTRANS_X];
            float transY = m[Matrix.MTRANS_Y];
            
            //
            // Width
            //
            float prevActualWidth = prevMatchViewWidth * normalizedScale;
            float actualWidth = getImageWidth();
            translateMatrixAfterRotate(Matrix.MTRANS_X, transX, prevActualWidth, actualWidth, prevViewWidth, viewWidth, drawableWidth);
            
            //
            // Height
            //
            float prevActualHeight = prevMatchViewHeight * normalizedScale;
            float actualHeight = getImageHeight();
            translateMatrixAfterRotate(Matrix.MTRANS_Y, transY, prevActualHeight, actualHeight, prevViewHeight, viewHeight, drawableHeight);
            
            //
            // Set the matrix to the adjusted scale and translate values.
            //
            matrix.setValues(m);
        }
        fixTrans();
        setImageMatrix(matrix);
    }
    
    /**
     * Set view dimensions based on layout params
     * 
     * @param mode 
     * @param size
     * @param drawableWidth
     * @return
     */
    private int setViewSize(int mode, int size, int drawableWidth) {
      int viewSize;
      switch (mode) {
    case MeasureSpec.EXACTLY:
      viewSize = size;
      break;
      
    case MeasureSpec.AT_MOST:
      viewSize = Math.min(drawableWidth, size);
      break;
      
    case MeasureSpec.UNSPECIFIED:
      viewSize = drawableWidth;
      break;
      
    default:
      viewSize = size;
       break;
    }
      return viewSize;
    }
    
    /**
     * After rotating, the matrix needs to be translated. This function finds the area of image 
     * which was previously centered and adjusts translations so that is again the center, post-rotation.
     * 
     * @param axis Matrix.MTRANS_X or Matrix.MTRANS_Y
     * @param trans the value of trans in that axis before the rotation
     * @param prevImageSize the width/height of the image before the rotation
     * @param imageSize width/height of the image after rotation
     * @param prevViewSize width/height of view before rotation
     * @param viewSize width/height of view after rotation
     * @param drawableSize width/height of drawable
     */
    private void translateMatrixAfterRotate(int axis, float trans, float prevImageSize, float imageSize, int prevViewSize, int viewSize, int drawableSize) {
      if (imageSize < viewSize) {
          //
          // The width/height of image is less than the view's width/height. Center it.
          //
          m[axis] = (viewSize - (drawableSize * m[Matrix.MSCALE_X])) * 0.5f;
          
        } else if (trans > 0) {
          //
          // The image is larger than the view, but was not before rotation. Center it.
          //
          m[axis] = -((imageSize - viewSize) * 0.5f);
          
        } else {
          //
          // Find the area of the image which was previously centered in the view. Determine its distance
          // from the left/top side of the view as a fraction of the entire image's width/height. Use that percentage
          // to calculate the trans in the new view width/height.
          //
          float percentage = (Math.abs(trans) + (0.5f * prevViewSize)) / prevImageSize;
          m[axis] = -((percentage * imageSize) - (viewSize * 0.5f));
        }
    }
    
    private void setState(State state) {
      this.state = state;
    }
    
    public boolean canScrollHorizontallyFroyo(int direction) {
        return canScrollHorizontally(direction);
    }
    
    @Override
    public boolean canScrollHorizontally(int direction) {
      matrix.getValues(m);
      float x = m[Matrix.MTRANS_X];
      
      if (getImageWidth() < viewWidth) {
        return false;
        
      } else if (x >= -1 && direction < 0) {
        return false;
        
      } else if (Math.abs(x) + viewWidth + 1 >= getImageWidth() && direction > 0) {
        return false;
      }
      
      return true;
    }
    
    /**
     * Gesture Listener detects a single click or long click and passes that on
     * to the view's listener.
     * @author Ortiz
     *
     */
    private class GestureListener extends GestureDetector.SimpleOnGestureListener {
      
        @Override
        public boolean onSingleTapConfirmed(MotionEvent e)
        {
            if(doubleTapListener != null) {
              return doubleTapListener.onSingleTapConfirmed(e);
            }
          return performClick();
        }
        
        @Override
        public void onLongPress(MotionEvent e)
        {
          performLongClick();
        }
        
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
        {
          if (fling != null) {
            //
            // If a previous fling is still active, it should be cancelled so that two flings
            // are not run simultaenously.
            //
            fling.cancelFling();
          }
          fling = new Fling((int) velocityX, (int) velocityY);
          compatPostOnAnimation(fling);
          return super.onFling(e1, e2, velocityX, velocityY);
        }
        
        @Override
        public boolean onDoubleTap(MotionEvent e) {
          boolean consumed = false;
            if(doubleTapListener != null) {
              consumed = doubleTapListener.onDoubleTap(e);
            }
          if (state == State.NONE) {
            float targetZoom = (normalizedScale == minScale) ? maxScale : minScale;
            DoubleTapZoom doubleTap = new DoubleTapZoom(targetZoom, e.getX(), e.getY(), false);
            compatPostOnAnimation(doubleTap);
            consumed = true;
          }
          return consumed;
        }

        @Override
        public boolean onDoubleTapEvent(MotionEvent e) {
            if(doubleTapListener != null) {
              return doubleTapListener.onDoubleTapEvent(e);
            }
            return false;
        }
    }
    
    public interface OnTouchImageViewListener {
      public void onMove();
    }
    
    /**
     * Responsible for all touch events. Handles the heavy lifting of drag and also sends
     * touch events to Scale Detector and Gesture Detector.
     * @author Ortiz
     *
     */
    private class PrivateOnTouchListener implements OnTouchListener {
      
      //
        // Remember last point position for dragging
        //
        private PointF last = new PointF();
      
      @Override
        public boolean onTouch(View v, MotionEvent event) {
            mScaleDetector.onTouchEvent(event);
            mGestureDetector.onTouchEvent(event);
            PointF curr = new PointF(event.getX(), event.getY());
            
            if (state == State.NONE || state == State.DRAG || state == State.FLING) {
              switch (event.getAction()) {
                  case MotionEvent.ACTION_DOWN:
                    last.set(curr);
                      if (fling != null)
                        fling.cancelFling();
                      setState(State.DRAG);
                      break;
                      
                  case MotionEvent.ACTION_MOVE:
                      if (state == State.DRAG) {
                          float deltaX = curr.x - last.x;
                          float deltaY = curr.y - last.y;
                          float fixTransX = getFixDragTrans(deltaX, viewWidth, getImageWidth());
                          float fixTransY = getFixDragTrans(deltaY, viewHeight, getImageHeight());
                          matrix.postTranslate(fixTransX, fixTransY);
                          fixTrans();
                          last.set(curr.x, curr.y);
                      }
                      break;
  
                  case MotionEvent.ACTION_UP:
                  case MotionEvent.ACTION_POINTER_UP:
                      setState(State.NONE);
                      break;
              }
            }
            
            setImageMatrix(matrix);
            
            //
        // User-defined OnTouchListener
        //
        if(userTouchListener != null) {
          userTouchListener.onTouch(v, event);
        }
            
        //
        // OnTouchImageViewListener is set: TouchImageView dragged by user.
        //
        if (touchImageViewListener != null) {
          touchImageViewListener.onMove();
        }
        
            //
            // indicate event was handled
            //
            return true;
        }
    }

    /**
     * ScaleListener detects user two finger scaling and scales image.
     * @author Ortiz
     *
     */
    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScaleBegin(ScaleGestureDetector detector) {
            setState(State.ZOOM);
            return true;
        }

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
          scaleImage(detector.getScaleFactor(), detector.getFocusX(), detector.getFocusY(), true);
          
          //
          // OnTouchImageViewListener is set: TouchImageView pinch zoomed by user.
          //
          if (touchImageViewListener != null) {
            touchImageViewListener.onMove();
          }
            return true;
        }
        
        @Override
        public void onScaleEnd(ScaleGestureDetector detector) {
          super.onScaleEnd(detector);
          setState(State.NONE);
          boolean animateToZoomBoundary = false;
          float targetZoom = normalizedScale;
          if (normalizedScale > maxScale) {
            targetZoom = maxScale;
            animateToZoomBoundary = true;
            
          } else if (normalizedScale < minScale) {
            targetZoom = minScale;
            animateToZoomBoundary = true;
          }
          
          if (animateToZoomBoundary) {
            DoubleTapZoom doubleTap = new DoubleTapZoom(targetZoom, viewWidth / 2, viewHeight / 2, true);
            compatPostOnAnimation(doubleTap);
          }
        }
    }
    
    private void scaleImage(double deltaScale, float focusX, float focusY, boolean stretchImageToSuper) {
      
      float lowerScale, upperScale;
      if (stretchImageToSuper) {
        lowerScale = superMinScale;
        upperScale = superMaxScale;
        
      } else {
        lowerScale = minScale;
        upperScale = maxScale;
      }
      
      float origScale = normalizedScale;
        normalizedScale *= deltaScale;
        if (normalizedScale > upperScale) {
            normalizedScale = upperScale;
            deltaScale = upperScale / origScale;
        } else if (normalizedScale < lowerScale) {
            normalizedScale = lowerScale;
            deltaScale = lowerScale / origScale;
        }
        
        matrix.postScale((float) deltaScale, (float) deltaScale, focusX, focusY);
        fixScaleTrans();
    }
    
    /**
     * DoubleTapZoom calls a series of runnables which apply
     * an animated zoom in/out graphic to the image.
     * @author Ortiz
     *
     */
    private class DoubleTapZoom implements Runnable {
      
      private long startTime;
      private static final float ZOOM_TIME = 500;
      private float startZoom, targetZoom;
      private float bitmapX, bitmapY;
      private boolean stretchImageToSuper;
      private AccelerateDecelerateInterpolator interpolator = new AccelerateDecelerateInterpolator();
      private PointF startTouch;
      private PointF endTouch;

      DoubleTapZoom(float targetZoom, float focusX, float focusY, boolean stretchImageToSuper) {
        setState(State.ANIMATE_ZOOM);
        startTime = System.currentTimeMillis();
        this.startZoom = normalizedScale;
        this.targetZoom = targetZoom;
        this.stretchImageToSuper = stretchImageToSuper;
        PointF bitmapPoint = transformCoordTouchToBitmap(focusX, focusY, false);
        this.bitmapX = bitmapPoint.x;
        this.bitmapY = bitmapPoint.y;
        
        //
        // Used for translating image during scaling
        //
        startTouch = transformCoordBitmapToTouch(bitmapX, bitmapY);
        endTouch = new PointF(viewWidth / 2, viewHeight / 2);
      }

    @Override
    public void run() {
      float t = interpolate();
      double deltaScale = calculateDeltaScale(t);
      scaleImage(deltaScale, bitmapX, bitmapY, stretchImageToSuper);
      translateImageToCenterTouchPosition(t);
      fixScaleTrans();
      setImageMatrix(matrix);
      
      //
      // OnTouchImageViewListener is set: double tap runnable updates listener
      // with every frame.
      //
      if (touchImageViewListener != null) {
        touchImageViewListener.onMove();
      }
      
      if (t < 1f) {
        //
        // We haven't finished zooming
        //
        compatPostOnAnimation(this);
        
      } else {
        //
        // Finished zooming
        //
        setState(State.NONE);
      }
    }
    
    /**
     * Interpolate between where the image should start and end in order to translate
     * the image so that the point that is touched is what ends up centered at the end
     * of the zoom.
     * @param t
     */
    private void translateImageToCenterTouchPosition(float t) {
      float targetX = startTouch.x + t * (endTouch.x - startTouch.x);
      float targetY = startTouch.y + t * (endTouch.y - startTouch.y);
      PointF curr = transformCoordBitmapToTouch(bitmapX, bitmapY);
      matrix.postTranslate(targetX - curr.x, targetY - curr.y);
    }
    
    /**
     * Use interpolator to get t
     * @return
     */
    private float interpolate() {
      long currTime = System.currentTimeMillis();
      float elapsed = (currTime - startTime) / ZOOM_TIME;
      elapsed = Math.min(1f, elapsed);
      return interpolator.getInterpolation(elapsed);
    }
    
    /**
     * Interpolate the current targeted zoom and get the delta
     * from the current zoom.
     * @param t
     * @return
     */
    private double calculateDeltaScale(float t) {
      double zoom = startZoom + t * (targetZoom - startZoom);
      return zoom / normalizedScale;
    }
    }
    
    /**
     * This function will transform the coordinates in the touch event to the coordinate 
     * system of the drawable that the imageview contain
     * @param x x-coordinate of touch event
     * @param y y-coordinate of touch event
     * @param clipToBitmap Touch event may occur within view, but outside image content. True, to clip return value
     *       to the bounds of the bitmap size.
     * @return Coordinates of the point touched, in the coordinate system of the original drawable.
     */
    private PointF transformCoordTouchToBitmap(float x, float y, boolean clipToBitmap) {
         matrix.getValues(m);
         float origW = getDrawable().getIntrinsicWidth();
         float origH = getDrawable().getIntrinsicHeight();
         float transX = m[Matrix.MTRANS_X];
         float transY = m[Matrix.MTRANS_Y];
         float finalX = ((x - transX) * origW) / getImageWidth();
         float finalY = ((y - transY) * origH) / getImageHeight();
         
         if (clipToBitmap) {
           finalX = Math.min(Math.max(finalX, 0), origW);
           finalY = Math.min(Math.max(finalY, 0), origH);
         }
         
         return new PointF(finalX , finalY);
    }
    
    /**
     * Inverse of transformCoordTouchToBitmap. This function will transform the coordinates in the
     * drawable's coordinate system to the view's coordinate system.
     * @param bx x-coordinate in original bitmap coordinate system
     * @param by y-coordinate in original bitmap coordinate system
     * @return Coordinates of the point in the view's coordinate system.
     */
    private PointF transformCoordBitmapToTouch(float bx, float by) {
        matrix.getValues(m);        
        float origW = getDrawable().getIntrinsicWidth();
        float origH = getDrawable().getIntrinsicHeight();
        float px = bx / origW;
        float py = by / origH;
        float finalX = m[Matrix.MTRANS_X] + getImageWidth() * px;
        float finalY = m[Matrix.MTRANS_Y] + getImageHeight() * py;
        return new PointF(finalX , finalY);
    }
    
    /**
     * Fling launches sequential runnables which apply
     * the fling graphic to the image. The values for the translation
     * are interpolated by the Scroller.
     * @author Ortiz
     *
     */
    private class Fling implements Runnable {
      
        CompatScroller scroller;
      int currX, currY;
      
      Fling(int velocityX, int velocityY) {
        setState(State.FLING);
        scroller = new CompatScroller(context);
        matrix.getValues(m);
        
        int startX = (int) m[Matrix.MTRANS_X];
        int startY = (int) m[Matrix.MTRANS_Y];
        int minX, maxX, minY, maxY;
        
        if (getImageWidth() > viewWidth) {
          minX = viewWidth - (int) getImageWidth();
          maxX = 0;
          
        } else {
          minX = maxX = startX;
        }
        
        if (getImageHeight() > viewHeight) {
          minY = viewHeight - (int) getImageHeight();
          maxY = 0;
          
        } else {
          minY = maxY = startY;
        }
        
        scroller.fling(startX, startY, (int) velocityX, (int) velocityY, minX,
                    maxX, minY, maxY);
        currX = startX;
        currY = startY;
      }
      
      public void cancelFling() {
        if (scroller != null) {
          setState(State.NONE);
          scroller.forceFinished(true);
        }
      }
      
    @Override
    public void run() {
      
      //
      // OnTouchImageViewListener is set: TouchImageView listener has been flung by user.
      // Listener runnable updated with each frame of fling animation.
      //
      if (touchImageViewListener != null) {
        touchImageViewListener.onMove();
      }
      
      if (scroller.isFinished()) {
            scroller = null;
            return;
          }
      
      if (scroller.computeScrollOffset()) {
            int newX = scroller.getCurrX();
              int newY = scroller.getCurrY();
              int transX = newX - currX;
              int transY = newY - currY;
              currX = newX;
              currY = newY;
              matrix.postTranslate(transX, transY);
              fixTrans();
              setImageMatrix(matrix);
              compatPostOnAnimation(this);
          }
    }
    }
    
    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
  private class CompatScroller {
      Scroller scroller;
      OverScroller overScroller;
      boolean isPreGingerbread;
      
      public CompatScroller(Context context) {
        if (VERSION.SDK_INT < VERSION_CODES.GINGERBREAD) {
          isPreGingerbread = true;
          scroller = new Scroller(context);
          
        } else {
          isPreGingerbread = false;
          overScroller = new OverScroller(context);
        }
      }
      
      public void fling(int startX, int startY, int velocityX, int velocityY, int minX, int maxX, int minY, int maxY) {
        if (isPreGingerbread) {
          scroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY);
        } else {
          overScroller.fling(startX, startY, velocityX, velocityY, minX, maxX, minY, maxY);
        }
      }
      
      public void forceFinished(boolean finished) {
        if (isPreGingerbread) {
          scroller.forceFinished(finished);
        } else {
          overScroller.forceFinished(finished);
        }
      }
      
      public boolean isFinished() {
        if (isPreGingerbread) {
          return scroller.isFinished();
        } else {
          return overScroller.isFinished();
        }
      }
      
      public boolean computeScrollOffset() {
        if (isPreGingerbread) {
          return scroller.computeScrollOffset();
        } else {
          overScroller.computeScrollOffset();
          return overScroller.computeScrollOffset();
        }
      }
      
      public int getCurrX() {
        if (isPreGingerbread) {
          return scroller.getCurrX();
        } else {
          return overScroller.getCurrX();
        }
      }
      
      public int getCurrY() {
        if (isPreGingerbread) {
          return scroller.getCurrY();
        } else {
          return overScroller.getCurrY();
        }
      }
    }
    
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
  private void compatPostOnAnimation(Runnable runnable) {
      if (VERSION.SDK_INT >= VERSION_CODES.JELLY_BEAN) {
            postOnAnimation(runnable);
            
        } else {
            postDelayed(runnable, 1000/60);
        }
    }
    
    private class ZoomVariables {
      public float scale;
      public float focusX;
      public float focusY;
      public ScaleType scaleType;
      
      public ZoomVariables(float scale, float focusX, float focusY, ScaleType scaleType) {
        this.scale = scale;
        this.focusX = focusX;
        this.focusY = focusY;
        this.scaleType = scaleType;
      }
    }
    
    private void printMatrixInfo() {
      float[] n = new float[9];
      matrix.getValues(n);
      Log.d(DEBUG, "Scale: " + n[Matrix.MSCALE_X] + " TransX: " + n[Matrix.MTRANS_X] + " TransY: " + n[Matrix.MTRANS_Y]);
    }
}




Java Source Code List

com.ortiz.touch.ExtendedViewPager.java
com.ortiz.touch.MainActivity.java
com.ortiz.touch.MirroringExampleActivity.java
com.ortiz.touch.SingleTouchImageViewActivity.java
com.ortiz.touch.SwitchImageExampleActivity.java
com.ortiz.touch.SwitchScaleTypeExampleActivity.java
com.ortiz.touch.TouchImageView.java
com.ortiz.touch.ViewPagerExampleActivity.java