code: private void mapAbsoluteToRelative(float[] destPoints, float[] srcPoints, int numPoints) {
      for (int i = 0; i < numPoints; i++) {
        destPoints[i * 2 + 0] = (srcPoints[i * 2 + 0] - mImageBounds.left) / mImageBounds.width();
        destPoints[i * 2 + 1] = (srcPoints[i * 2 + 1] - mImageBounds.top)  / mImageBounds.height();
      }
    }
docs: Maps array of 2D points from view-absolute to image-relative coordinates.
  This does NOT take into account the zoomable transformation.
  Points are represented by a float array of [x0, y0, x1, y1, ...].
  
  @param destPoints destination array (may be the same as source array)
  @param srcPoints source array
  @param numPoints number of points to map