GRAPHZOOM
Richard R. Burton 
Last revised: November 8, 1983
Copyright (c) 1983 Xerox Corporation
stored on: <LISP>LIBRARY>GRAPHZOOM


GRAPHZOOM allows the graphs (a la GRAPHER) to be worked with at difference scales.  The interface to it is through the function SHOWZOOMGRAPH which is used instead of SHOWGRAPH.  The resulting grapher window has the capability of being "zoomed" by using a menu that is attached to the top.  To use, call SHOWZOOMGRAPH:

SHOWZOOMGRAPH (GRAPH WINDOW LEFTBUTTONFN MIDDLEBUTTONFN TOPJUSTIFYFLG ALLOWEDITFLG INITSCALE)
The arguments are that same as SHOWGRAPH.  INITSCALE is the initial scale at which the graph is shown. 1.0 (the default) is the same as SHOWGRAPH.  Larger scales make the graph appear smaller.

The window will have a menu above it which contains the items 'LARGER' and 'smaller'.  Selecting in the menu with the left button will cause a small change in scale; with the middle button will cause a larger change in scale.

The graph will zoom toward the center of the window.

The zooming of text is driven off a list of font descriptors stored as the value of the variable DECREASING.FONT.LIST.  The values on this list are Times Roman 72, 36, 30, Helvetica 24, 18, 14, 12, 10, 8, 5, 4, and 3.  Graphs which have fonts other than Helvetica will get printed in the closest Helvetica size.  This is often smaller than the corresponding GACHA font.