private RectF getDisplayRect(Matrix matrix) {
        Drawable d = mImageView.getDrawable();
        if (d != null) {
            mDisplayRect.set(0, 0, d.getIntrinsicWidth(),
                    d.getIntrinsicHeight());
            matrix.mapRect(mDisplayRect);
            return mDisplayRect;
        }
        return null;
    }
Helper method that maps the supplied Matrix to the current Drawable

@param matrix - Matrix to map Drawable against
@return RectF - Displayed Rectangle
main/src/main/java/com/quxianggif/common/view/photoview/PhotoViewAttacher.java