question: protected Size2D arrangeFN ( BlockContainer container , Graphics2D g2 , RectangleConstraint constraint ) { List blocks = container . getBlocks ( ) ; Block b = ( Block ) blocks . get ( 0 ) ; Size2D s = b . arrange ( g2 , RectangleConstraint . NONE ) ; double width = constraint . getWidth ( ) ; Rectangle2D bounds = new Rectangle2D . Double ( ( width - s . width ) / 2.0 , 0.0 , s . width , s . height ) ; b . setBounds ( bounds ) ; return new Size2D ( ( width - s . width ) / 2.0 , s . height ) ; }
target:  Arranges the blocks in the container with a fixed width and no height constraint.