The calculate-layout generic function is used to provide a method for laying out the children of a new layout.
The generic function calculate-layout is called by the CAPI to layout the children of a layout. When defining a new class of layout using define-layout , a calculate-layout method must be provided that sets the x , y , width and height of each of the layout's children. This method must try to obey the constraints specified by its children (its minimum and maximum size) and should only break them when it becomes impossible to fit the constraints of all of the children.
To set the x , y , width and height of the layout, use the macro with-geometry which works in a similar way as with-slots .
In LispWorks 3.1, this macro and all of its variable names were in the capi-layouts package. They have been moved into the CAPI package for simplicity.