A window is a CLIM stream pane that supports all window and stream operations. Windows are primarily included for compatibility with CLIM 1.1, although it is sometimes useful to be able to perform operations directly on a window.
Clearing and Refreshing the Drawing Plane
CLIM supports the following operators for clearing and refreshing the drawing plane:
window-clear[Generic Function]
Summary: Clears the entire drawing plane of window, filling it with the background ink.
window-erase-viewport[Generic Function]
Summary: Clears the visible part of window's drawing plane, filling it with background ink.
window-refresh[Generic Function]
Summary: Clears the visible part of the drawing plane of window, and then replays all of the output records in the visible part of the drawing plane.
A window stream viewport is the region of the drawing plane that is visible through the window. You can change the viewport by scrolling or by reshaping the window. The viewport does not change if the window is covered by another window (that is, the viewport is the region of the drawing plane that would be visible if the window were on top).
A window stream has an end-of-line action and an end-of-page action, which control what happens when the cursor position moves out of the viewport ( with-end-of-line-action and with-end-of-page-action , respectively).
Viewport and Scrolling Operators
window-viewport[Generic Function]
Summary: Returns a region that is the window's current viewport, an object of type area . (10.2.3, Composite Pane Generic Functions for the generic function pane-viewport , which returns a viewport.)
window-viewport-position*[Generic Function]
Summary: Returns the x and y coordinates of the top-left corner of the window's viewport.
window-set-viewport-position*[Generic Function]
Summary: Moves the top-left corner of the window 's viewport. Use this to scroll a window.
Common Lisp Interface Manager 2.0 User's Guide - 7 Aug 2017