Android Touch imageview - pinch zoom
/*Cast ImageView to TouchImageView*/
ImageView imageView = (TouchImageView)findViewById(R.id.imageView);
how to define ni XML file
<com.example.TouchImageView android:id="@+id/imageView" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_centerInParent="true" />
Create class in yout Project TouchImageView.java
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(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(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]); } }
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