How to draw a circle after zoom in android

Question

I am using Image view and drawing overlay image using layerDrawable. I have used two bitmaps original and myBitmap. After zoom I am not able draw circle in correct location, it's drawn in different location.

This is the code I am using,

    ImageView view = (ImageView) findViewById(R.id.imageView);
    view.setOnTouchListener(this);

    Options options = new BitmapFactory.Options();
    options.inScaled = false;
    original = BitmapFactory.decodeResource(getResources(), R.drawable.mainscreen,options); 
    original= getResizedBitmap(original, width, 200);
    myBitmap = func(original);

    Resources r = getResources();
    layers = new Drawable[2];
    layers[0] = new BitmapDrawable(original);
    layers[1] = new BitmapDrawable(myBitmap);
    LayerDrawable layerDrawable = new LayerDrawable(layers);
    view.setImageDrawable(layerDrawable);

    bitmap =  Bitmap.createBitmap(width, 200, Config.ARGB_8888);
    pcanvas = new Canvas();
    pcanvas.setBitmap(bitmap);  
    pcanvas.drawBitmap(grayScale, 0, 0, null);


   public boolean onTouch(View v, MotionEvent rawEvent) {
      WrapMotionEvent event = WrapMotionEvent.wrap(rawEvent);
      // ...
      ImageView view = (ImageView) v;

      // Dump touch event to log
     // dumpEvent(event);
      if (isZoomRequired == false)
      {
          x = (int) rawEvent.getX();
          y = (int) rawEvent.getY();
          r = SettingsActivity.brushsize;

          pcanvas.drawCircle(x, y, r, mPaint);
          layers[1] = new BitmapDrawable(bitmap);
          LayerDrawable layerDrawable = new LayerDrawable(layers);
          view.setImageDrawable(layerDrawable);

      }
      else
      {
      // Handle touch events here...
      switch (event.getAction() & MotionEvent.ACTION_MASK) {
      case MotionEvent.ACTION_DOWN:
         savedMatrix.set(matrix);
         start.set(event.getX(), event.getY());
         Log.d(TAG, "mode=DRAG");
         mode = DRAG;
         break;
      case MotionEvent.ACTION_POINTER_DOWN:
         oldDist = spacing(event);
         Log.d(TAG, "oldDist=" + oldDist);
         if (oldDist > 10f) {
            savedMatrix.set(matrix);
            midPoint(mid, event);
            mode = ZOOM;
            Log.d(TAG, "mode=ZOOM");
         }
         break;
      case MotionEvent.ACTION_UP:
      case MotionEvent.ACTION_POINTER_UP:
         mode = NONE;
         Log.d(TAG, "mode=NONE");
         break;
      case MotionEvent.ACTION_MOVE:
         if (mode == DRAG) {
            // ...
            matrix.set(savedMatrix);
            matrix.postTranslate(event.getX() - start.x,
                  event.getY() - start.y);
         }
         else if (mode == ZOOM) {
            float newDist = spacing(event);
            Log.d(TAG, "newDist=" + newDist);
            if (newDist > 10f) {
               matrix.set(savedMatrix);
               float scale = newDist / oldDist;
               matrix.postScale(scale, scale, mid.x, mid.y);
            }
         }
         break;
      }


      view.setImageMatrix(matrix);

      }
      return true; // indicate event was handled
   }

Kindly help me. I need to draw circle in correct location after zoom.

Any help would be appreciated.

Answer 1

Could you add images showing what it is you're trying to get and a pic showing what you get instead?

One thing to keep in mind is that certain operations use a different zero point for the y axis. I've been fighting this on matrix operations on a surfaceview, where I've had to calculate a correction factor because one operation used the top of the view as y=0 and the matrix operation used the bottom of the view as y=0, so the actual matrix operation needed something like: matrixY = (totalHeightY - Yposition).

But showing what you expect and what you're getting would help diagnose the problem quicker than running and working through your code :)