The generic function simple-pane-visible-width
returns the width in pixels of the visible part of
pane
, that is the width of the viewport, not including any borders or scroll bars. If
pane
is not displayed the function returns nil
.
See Width and height hints for a description of the visible size of a pane.
CAPI User Guide and Reference Manual (Macintosh version) - 3 Aug 2017