question: private boolean calculateBounds ( RectF rect ) { float left = BitmapUtils . getRectLeft ( mBoundsPoints ) ; float top = BitmapUtils . getRectTop ( mBoundsPoints ) ; float right = BitmapUtils . getRectRight ( mBoundsPoints ) ; float bottom = BitmapUtils . getRectBottom ( mBoundsPoints ) ; if ( isNonStraightAngleRotated ( ) ) { mCalcBounds . set ( left , top , right , bottom ) ; return false ; } else { float x0 = mBoundsPoints [ 0 ] ; float y0 = mBoundsPoints [ 1 ] ; float x2 = mBoundsPoints [ 4 ] ; float y2 = mBoundsPoints [ 5 ] ; float x3 = mBoundsPoints [ 6 ] ; float y3 = mBoundsPoints [ 7 ] ; if ( mBoundsPoints [ 7 ] < mBoundsPoints [ 1 ] ) { if ( mBoundsPoints [ 1 ] < mBoundsPoints [ 3 ] ) { x0 = mBoundsPoints [ 6 ] ; y0 = mBoundsPoints [ 7 ] ; x2 = mBoundsPoints [ 2 ] ; y2 = mBoundsPoints [ 3 ] ; x3 = mBoundsPoints [ 4 ] ; y3 = mBoundsPoints [ 5 ] ; } else { x0 = mBoundsPoints [ 4 ] ; y0 = mBoundsPoints [ 5 ] ; x2 = mBoundsPoints [ 0 ] ; y2 = mBoundsPoints [ 1 ] ; x3 = mBoundsPoints [ 2 ] ; y3 = mBoundsPoints [ 3 ] ; } } else if ( mBoundsPoints [ 1 ] > mBoundsPoints [ 3 ] ) { x0 = mBoundsPoints [ 2 ] ; y0 = mBoundsPoints [ 3 ] ; x2 = mBoundsPoints [ 6 ] ; y2 = mBoundsPoints [ 7 ] ; x3 = mBoundsPoints [ 0 ] ; y3 = mBoundsPoints [ 1 ] ; } float a0 = ( y3 - y0 ) / ( x3 - x0 ) ; float a1 = - 1f / a0 ; float b0 = y0 - a0 * x0 ; float b1 = y0 - a1 * x0 ; float b2 = y2 - a0 * x2 ; float b3 = y2 - a1 * x2 ; float c0 = ( rect . centerY ( ) - rect . top ) / ( rect . centerX ( ) - rect . left ) ; float c1 = - c0 ; float d0 = rect . top - c0 * rect . left ; float d1 = rect . top - c1 * rect . right ; left = Math . max ( left , ( d0 - b0 ) / ( a0 - c0 ) < rect . right ? ( d0 - b0 ) / ( a0 - c0 ) : left ) ; left = Math . max ( left , ( d0 - b1 ) / ( a1 - c0 ) < rect . right ? ( d0 - b1 ) / ( a1 - c0 ) : left ) ; left = Math . max ( left , ( d1 - b3 ) / ( a1 - c1 ) < rect . right ? ( d1 - b3 ) / ( a1 - c1 ) : left ) ; right = Math . min ( right , ( d1 - b1 ) / ( a1 - c1 ) > rect . left ? ( d1 - b1 ) / ( a1 - c1 ) : right ) ; right = Math . min ( right , ( d1 - b2 ) / ( a0 - c1 ) > rect . left ? ( d1 - b2 ) / ( a0 - c1 ) : right ) ; right = Math . min ( right , ( d0 - b2 ) / ( a0 - c0 ) > rect . left ? ( d0 - b2 ) / ( a0 - c0 ) : right ) ; top = Math . max ( top , Math . max ( a0 * left + b0 , a1 * right + b1 ) ) ; bottom = Math . min ( bottom , Math . min ( a1 * left + b3 , a0 * right + b2 ) ) ; mCalcBounds . left = left ; mCalcBounds . top = top ; mCalcBounds . right = right ; mCalcBounds . bottom = bottom ; return true ; } }
target:  Calculate the bounding rectangle for current crop window, handle non-straight rotation angles.<br> If the rotation angle is straight then the bounds rectangle is the bitmap rectangle, otherwsie we find the max rectangle that is within the image bounds starting from the crop window rectangle.