set-scroll-range

Arguments: window x-max y-max &optional x-thumb-length y-thumb-length

This function should be called by an application only as part of a custom scrolling scheme that is implemented by overriding several default Common Graphics methods in order to scroll by logical picture objects rather than by pixels. This symbol is exported because it is one of the generic functions that need to be modified. See the example entitled "Scrolling by arbitrary objects rather than pixels" on the Examples tab of the Navigator dialog for a complete example and see the descriptions of horizontal-scroll-bar and vertical-scroll-bar.

When the default Common Graphics scrolling code (which always scrolls by pixels) is used, an application should set the page size of a window rather than calling this function to set the scroll-range. The page size may be set either by passing the :page-width and/or :page-height initargs to make-window or by calling set-page-size later. The page size is the size of the entire canvas that may be scrolled into the window. The scroll-range is the portion of the page size that does not fit into the window interior. So by setting the page size, the scroll-range is determined implicitly, including the "thumb" (scroll-box) lengths which correspond to the interior size of the window compared to the page size.

In releases prior to 6.0, setting the scroll-range of a window would automatically set its page size to match; this is no longer done. Applications should set the page size instead, as described above in this entry.

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Created 2010.1.21.