mirror of https://github.com/M66B/FairEmail.git
M66B
6 years ago
parent
a087e79c5e
commit
cebd727209
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package eu.faircode.email;
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import android.content.Context;
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import android.graphics.Matrix;
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import android.graphics.PointF;
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import android.graphics.drawable.Drawable;
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import android.util.AttributeSet;
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import android.view.MotionEvent;
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import android.view.ScaleGestureDetector;
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import android.widget.ImageView;
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/**
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* Created by alex on 23/02/16.
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* Based on code posted by Nicolas Tyler here:
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* https://stackoverflow.com/questions/6650398/android-imageview-zoom-in-and-zoom-out
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*/
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public class ZoomableImageView extends ImageView {
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private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
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@Override
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public boolean onScaleBegin(ScaleGestureDetector detector) {
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mode = ZOOM;
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return true;
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}
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@Override
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public boolean onScale(ScaleGestureDetector detector) {
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float scaleFactor = detector.getScaleFactor();
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float newScale = saveScale * scaleFactor;
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if (newScale < maxScale && newScale > minScale) {
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saveScale = newScale;
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float width = getWidth();
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float height = getHeight();
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right = (originalBitmapWidth * saveScale) - width;
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bottom = (originalBitmapHeight * saveScale) - height;
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float scaledBitmapWidth = originalBitmapWidth * saveScale;
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float scaledBitmapHeight = originalBitmapHeight * saveScale;
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if (scaledBitmapWidth <= width || scaledBitmapHeight <= height) {
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matrix.postScale(scaleFactor, scaleFactor, width / 2, height / 2);
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} else {
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matrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY());
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}
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}
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return true;
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}
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}
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static final int NONE = 0;
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static final int DRAG = 1;
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static final int ZOOM = 2;
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static final int CLICK = 3;
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private int mode = NONE;
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private Matrix matrix = new Matrix();
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private PointF last = new PointF();
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private PointF start = new PointF();
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private float minScale = 0.5f;
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private float maxScale = 4f;
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private float[] m;
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private float redundantXSpace, redundantYSpace;
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private float saveScale = 1f;
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private float right, bottom, originalBitmapWidth, originalBitmapHeight;
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private ScaleGestureDetector mScaleDetector;
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public ZoomableImageView(Context context) {
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super(context);
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init(context);
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}
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public ZoomableImageView(Context context, AttributeSet attrs) {
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super(context, attrs);
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init(context);
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}
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public ZoomableImageView(Context context, AttributeSet attrs, int defStyleAttr) {
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super(context, attrs, defStyleAttr);
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init(context);
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}
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private void init(Context context) {
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super.setClickable(true);
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mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
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m = new float[9];
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setImageMatrix(matrix);
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setScaleType(ScaleType.MATRIX);
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}
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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super.onMeasure(widthMeasureSpec, heightMeasureSpec);
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int bmHeight = getBmHeight();
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int bmWidth = getBmWidth();
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float width = getMeasuredWidth();
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float height = getMeasuredHeight();
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//Fit to screen.
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float scale = width > height ? height / bmHeight : width / bmWidth;
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matrix.setScale(scale, scale);
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saveScale = 1f;
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originalBitmapWidth = scale * bmWidth;
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originalBitmapHeight = scale * bmHeight;
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// Center the image
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redundantYSpace = (height - originalBitmapHeight);
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redundantXSpace = (width - originalBitmapWidth);
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matrix.postTranslate(redundantXSpace / 2, redundantYSpace / 2);
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setImageMatrix(matrix);
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}
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@Override
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public boolean onTouchEvent(MotionEvent event) {
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mScaleDetector.onTouchEvent(event);
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matrix.getValues(m);
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float x = m[Matrix.MTRANS_X];
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float y = m[Matrix.MTRANS_Y];
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PointF curr = new PointF(event.getX(), event.getY());
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switch (event.getAction()) {
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//when one finger is touching
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//set the mode to DRAG
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case MotionEvent.ACTION_DOWN:
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last.set(event.getX(), event.getY());
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start.set(last);
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mode = DRAG;
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break;
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//when two fingers are touching
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//set the mode to ZOOM
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case MotionEvent.ACTION_POINTER_DOWN:
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last.set(event.getX(), event.getY());
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start.set(last);
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mode = ZOOM;
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break;
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//when a finger moves
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//If mode is applicable move image
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case MotionEvent.ACTION_MOVE:
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//if the mode is ZOOM or
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//if the mode is DRAG and already zoomed
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if (mode == ZOOM || (mode == DRAG && saveScale > minScale)) {
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float deltaX = curr.x - last.x;// x difference
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float deltaY = curr.y - last.y;// y difference
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float scaleWidth = Math.round(originalBitmapWidth * saveScale);// width after applying current scale
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float scaleHeight = Math.round(originalBitmapHeight * saveScale);// height after applying current scale
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boolean limitX = false;
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boolean limitY = false;
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//if scaleWidth is smaller than the views width
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//in other words if the image width fits in the view
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//limit left and right movement
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if (scaleWidth < getWidth() && scaleHeight < getHeight()) {
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// don't do anything
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}
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else if (scaleWidth < getWidth()) {
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deltaX = 0;
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limitY = true;
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}
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//if scaleHeight is smaller than the views height
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//in other words if the image height fits in the view
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//limit up and down movement
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else if (scaleHeight < getHeight()) {
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deltaY = 0;
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limitX = true;
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}
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//if the image doesnt fit in the width or height
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//limit both up and down and left and right
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else {
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limitX = true;
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limitY = true;
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}
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if (limitY) {
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if (y + deltaY > 0) {
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deltaY = -y;
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} else if (y + deltaY < -bottom) {
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deltaY = -(y + bottom);
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}
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}
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if (limitX) {
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if (x + deltaX > 0) {
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deltaX = -x;
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} else if (x + deltaX < -right) {
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deltaX = -(x + right);
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}
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}
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//move the image with the matrix
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matrix.postTranslate(deltaX, deltaY);
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//set the last touch location to the current
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last.set(curr.x, curr.y);
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}
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break;
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//first finger is lifted
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case MotionEvent.ACTION_UP:
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mode = NONE;
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int xDiff = (int) Math.abs(curr.x - start.x);
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int yDiff = (int) Math.abs(curr.y - start.y);
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if (xDiff < CLICK && yDiff < CLICK)
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performClick();
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break;
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// second finger is lifted
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case MotionEvent.ACTION_POINTER_UP:
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mode = NONE;
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break;
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}
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setImageMatrix(matrix);
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invalidate();
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return true;
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}
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public void setMaxZoom(float x) {
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maxScale = x;
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}
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private int getBmWidth() {
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Drawable drawable = getDrawable();
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if (drawable != null) {
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return drawable.getIntrinsicWidth();
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}
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return 0;
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}
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private int getBmHeight() {
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Drawable drawable = getDrawable();
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if (drawable != null) {
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return drawable.getIntrinsicHeight();
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}
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return 0;
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}
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}
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