Zoom the horizontal scale of a stacked-tree.
capi
stacked-tree-zoom-by-factor stacked-tree factor => width-ratio
| stacked-tree⇩ | 
A stacked-tree. | 
| factor⇩ | 
A non-negative real. | 
| width-ratio⇩ | 
A real. | 
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.
Evaluating the form:
(stacked-tree-zoom-by-factor stacked-tree factor)
is equivalent to:
(setf (stacked-tree-width-ratio stacked-tree)
      (* (stacked-tree-width-ratio stacked-tree)
         factor))
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:32:42