This directory contains a variety of  VAX  BASIC  program  examples  that  use
graphics  statements.   They  are  provided to show possible uses of VAX BASIC
graphics statements.  The contents of this directory should not be  considered
a supported part of the product, and may change from release to release.

The following is a summary of what you will find in this directory:

     1.  BASIC_EXAMPLES.COM - A command procedure to run the examples in  this
         directory.

     2.  BASIC$GRAPHICS.TLB - A text  library  containing  the  sources  to  a
         variety  of  subprograms  and  picture  routines.   You  may use this
         library directly via the %INCLUDE %FROM %LIBRARY directive or you may
         link with the compiled forms of these routines in the supplied object
         library.

     3.  BASIC$GRAPHICS.OLB - An object library containing the object code for
         the  routines  in  BASIC$GRAPHICS.TLB.   The  following  routines are
         included in both the text and object library:

          o  ASK_REALIZED_DEVICE_VIEWPORT - This SUB can be called in place of
             the  ASK DEVICE VIEWPORT statement to maintain compatibility with
             VAX GKS V2.0.  If your program's device viewport  boundaries  are
             not proportional to the device window boundaries, VAX GKS adjusts
             the device viewport boundaries to maintain a  1:1  aspect  ratio.
             These  adjusted  or  "realized" device viewport boundaries may be
             different  from  those  specified  in  a  SET   DEVICE   VIEWPORT
             statement.

             When using VAX  GKS  V2.0,  the  ASK  DEVICE  VIEWPORT  statement
             returns  "realized"  device  viewport boundaries.  When using VAX
             GKS V3.0 or later, the ASK DEVICE VIEWPORT statement returns  the
             currently  set  device  viewport  boundaries.  You can obtain the
             "realized"    device    viewport    boundaries     by     calling
             ASK_REALIZED_DEVICE_VIEWPORT.   This  routine  accepts  the  same
             arguments as the ASK DEVICE VIEWPORT statement.

          o  CIRCLE -  When  invoked  with  a  DRAW  statement,  this  PICTURE
             subroutine  will  draw a circle at the X,Y point indicated by the
             first two parameters, with the radius specified in Y  coordinates
             by  the  third  parameter.   This  PICTURE  will  account for any
             transformations that may be in affect at the time the PICTURE  is
             invoked.  This PICTURE calls ASK_REALIZED_DEVICE_VIEWPORT.

          o  ENTIRE_SCREEN - By default, GKS graphics  output  uses  a  square
             portion  of  the output device.  This SUB can be CALLed to modify
             the transformations so that any further graphic output  will  use
             the  entire  graphic  output  device.   Beware that the VIEWPORT,
             DEVICE WINDOW, and  DEVICE  VIEWPORT  are  modified  during  this
             operation.

          o  PIE - This SUB will plot a pie chart from a  set  of  values  and
             labels.   The program PIE_DRIVER is provided as an example of the
             use of PIE and allows the user to  input  a  set  of  labels  and
             values to plot in pie chart form.

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          o  PLOT - This SUB will accept arrays of X,Y points and plot a graph
             of the values in the arrays.  PLOT_DRIVER.BAS is provided to show
             an example of the use of PLOT, and allows the user to either plot
             a  pre-determined  set of X,Y pairs or enter a group of X,Y pairs
             to plot.

          o  SQUARE - This PICTURE routine will plot a square of  a  specified
             color and size.

          o  HISTOGRAM - This is a PICTURE routine that draws histograms.


     4.  CLOCK.BAS displays a running analog clock.

     5.  DRAW_HISTOGRAM.BAS demonstrates the use of the HISTOGRAM subroutine.

     6.  FONT_DEMO.BAS demonstrates the available text fonts.

     7.  ELLIPSE.BAS, ROTATED_SQUARES.BAS, CREATE_SWAN_SWIM.BAS,  PARTY.BAS  -
         These  routines  are general output examples, many which can be found
         in the V3.0 documentation.  There  are  many  examples  which  invoke
         PICTURE   subprograms   with  various  transformations  within  these
         programs.

     8.  SINE.BAS produces a simple SINE curve.