ImageView Zoom in And Zoom out

May 30, 2016 , 0 Comments

Use this imageview :

How to use this :
<com.view.TouchImageView              \\ this package name whereever your keep this class.
android:id="@+id/iv"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
android:src="@drawable/backgroundimage"
android:transitionName="@string/venueImage"
android:visibility="visible" />


this ImageClass What we are used




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 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) {
return doubleTapListener != null && doubleTapListener.onDoubleTapEvent(e);
}
}

public interface OnTouchImageViewListener {
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, velocityX, 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]);
}
}

Contributer

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