The margin is proportional to the size of the image. It increases the view port beyond the value returned by viewPort or set by ViewPort.
i1 : Circle{"fill"=>"red","stroke"=>"none",Margin=>0} o1 = Circle{cache => CacheTable{}} Center => | 0 | | 0 | | 0 | | 1 | fill => red Margin => 0 Radius => 50 stroke => none o1 : Circle |
i2 : Circle{"fill"=>"red","stroke"=>"none",Margin=>0.5} o2 = Circle{cache => CacheTable{}} Center => | 0 | | 0 | | 0 | | 1 | fill => red Margin => .5 Radius => 50 stroke => none o2 : Circle |