I use Matrix to scale images, but how can I know the scaled image size in a simple manner?
My code is as follows:
public class MainActivity extends Activity {
private final String TAG = "MainActivity";
private ImageView mImageView;
private Button btnin, btnout;
int imageid = 0;
LinearLayout mlayout;
private float scaleWidth = 1, scaleHeight = 1;
private final static int NONE = 0;
private final static int DRAG = 1;
private final static int ZOOM = 2;
private int mode = NONE;
private Matrix matrix;
private Matrix currentMatrix;
private PointF startPoint;
private PointF midPoint;
private float startDistance;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mlayout = (LinearLayout) findViewById(R.id.mlayout);
mImageView = (ImageView) findViewById(R.id.myImageView);
matrix = new Matrix();
currentMatrix = new Matrix();
startPoint = new PointF();
btnin = (Button) findViewById(R.id.myButton1);
btnout = (Button) findViewById(R.id.myButton2);
btnout.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
zoomOut();
}
});
btnin.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
zoomIn();
}
});
mImageView.setOnTouchListener(new ImageViewOnTouchListener());
}
private void reSetImage(double d) {
Matrix matrix=new Matrix();
scaleWidth *= d;
scaleHeight *= d;
matrix.postScale(scaleWidth, scaleHeight);
mImageView.setImageMatrix(matrix);
}
private void zoomIn() {
reSetImage(0.8);
}
private void zoomOut() {
reSetImage(1.2);
}
@SuppressLint("NewApi")
class ImageViewOnTouchListener implements OnTouchListener {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
matrix.set(view.getImageMatrix());
currentMatrix.set(matrix);
startPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_UP:
mode = NONE;
Log.i(TAG, "up");
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
Log.i(TAG, "pointer up");
break;
case MotionEvent.ACTION_POINTER_DOWN: {
startDistance = distance(event);
if (startDistance > 15f) {
currentMatrix.set(matrix);
midPoint = getMidPoint(event);
Log.i(TAG, "midpoint:" + "X:" + midPoint.x + " Y:"
+ midPoint.y);
mode = ZOOM;
}
}
break;
case MotionEvent.ACTION_MOVE: {
if (mode == DRAG) {
float dx = event.getX() - startPoint.x;
float dy = event.getY() - startPoint.y;
matrix.set(currentMatrix);
matrix.postTranslate(dx, dy);
Log.i(TAG, "action move");
} else if (mode == ZOOM) {
float distance = distance(event);
if (distance > 15f) {
matrix.set(currentMatrix);
float scale = distance / startDistance;
matrix.postScale(scale, scale, midPoint.x, midPoint.y);
}
}
}
break;
default:
break;
}
mImageView.setImageMatrix(matrix);
mImageView.invalidate();
return true;
}
}
private float distance(MotionEvent event) {
float ex = event.getX(1) - event.getX(0);
float ey = event.getY(1) - event.getY(0);
return FloatMath.sqrt(ex * ex + ey * ey);
}
private PointF getMidPoint(MotionEvent event) {
float x = (event.getX(1) + event.getX(0)) / 2;
float y = (event.getY(1) + event.getY(0)) / 2;
return new PointF(x, y);
}
}
ImageView class inherits from View class, which has getWidth() and getHeight(). These methods return the measurements in pixels for you. So all you need to do is call mImageView.getWidth() and it will return an int.