content: /*
   * Copyright 2015 XiNGRZ <chenxingyu92@gmail.com>
   *
   * 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.
   */
  
  /*
   * TouchImageView.java
   * 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.
   *
   * URL:
   * https://github.com/MikeOrtiz/TouchImageView/blob/master/src/com/ortiz/touch/TouchImageView.java
   */
  
  package info.meizi.widget;
  
  import android.annotation.SuppressLint;
  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.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(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
          @SuppressLint("ClickableViewAccessibility")
          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(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(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]);
      }
  }
  