Arguments: stream scroll-type new-position
This function is called by the system whenever the user makes a scrolling gesture. It should not be called directly by the program, but may be modified to customize scrolling behavior on the program's own window classes.
scroll-type is one of :left, :right, :up, :down, :thumb-continuous, :thumb-finished. The thumb values indicate a dragged scroll-box (also known as "the thumb" or "slider"), while the other values indicate single-click page or line scrolling.
new-position is either :character or :page. :character indicates that a small (line or character) scroll was requested, typically by mousing one of the arrows at the end of the scroll bar or by pressing the arrow keys on the keyboard. :page indicates that a large (page) scroll was requested, typically by mousing the body of the scroll bar or pressing the page-up or page-down keys.
An application may override the default method of this and several
other generic functions in order to implement a custom scrolling
scheme that scrolls by logical picture objects rather than by
pixels. See the source code of the Navigator example entitled
'Scrolling by arbitrary objects rather than pixels' for a complete
example." More on this point and a list of the relevant generic
functions can be found on the horizontal-scroll-bar and vertical-scroll-bar
pages.
See About events in the IDE in cgide.htm.
Common Graphics and IDE documentation is described in About Common Graphics and IDE documentation in cgide.htm.
The documentation is described in introduction.htm and the index is in index.htm.
Copyright (c) 1998-2000, Franz Inc. Berkeley, CA., USA. All rights reserved.
Created 2000.10.5.