




Zoom the horizontal scale of a stacked-tree.
The function stacked-tree-zoom-by-factor expands the horizontal dimension of 
stacked-tree
 by 
factor
. If 
factor
 is between 0 and 1, the horizontal dimension contracts.
This is the same operation as is done by the keyboard gestures Ctrl--, Ctrl-+, Ctrl-i and Ctrl-o and you can use it to implement your own gestures.
The returned width-ratio is the value returned by stacked-tree-width-ratio.
(stacked-tree-zoom-by-factor stacked-tree factor)
(setf (stacked-tree-width-ratio stacked-tree)
(* (stacked-tree-width-ratio stacked-tree)
factor))
CAPI User Guide and Reference Manual (Windows version) - 3 Aug 2017