SAS/GRAPH Software: Reference |
The DATA Step Graphics
Interface (DSGI) enables you to create graphics output within the DATA step
or from within an SCL application. Through DSGI, you can call the graphics
routines used by SAS/GRAPH software
to generate an entire custom graph or to add features to an existing graph.
You can use DSGI to write a custom graphics application in conjunction with
all the power of the programming statements accessible by the DATA step.
DSGI provides many of
the same features as the Annotate facility, but it also has many advantages
over the Annotate facility.
- You can use DSGI functions and routines through
SCL.
- You can save disk space. DSGI graphics can be
generated through the DATA step without creating an output data set. The
graphics output is stored as a catalog entry in the catalog you select and,
optionally, is displayed after the DATA step is submitted.
- DSGI generates graphics faster than the Annotate
facility. With the Annotate facility, you must first create a data set and
then submit a PROC step to display the graphics output. In DSGI, you eliminate
the PROC step because the graphics output is generated after the DATA step.
- DSGI supports viewports and windows, which enable
you to specify the dimensions, position, and scale of the graphics output.
They also allow you to include multiple graphs in the same graphics output.
You should consider using the Annotate facility for
enhancing procedure output and using DSGI for creating custom graphics without
using a graphics procedure.
DSGI is based upon the Graphics Kernal System (GKS) standard,
although it does not follow a strict interpretation, nor is it implemented
on a particular level of GKS. GKS was used to provide a recognizable interface
to the user. Because of its modularity, the standard allows for enhancements
to DSGI without the side effect of converting programs between versions of
SAS/GRAPH software.
This chapter explains the concepts used to create graphics
output with DSGI. The discussion provides an overview of the functions and
routines used in DSGI. For complete details of each function and routine,
see DATA Step Graphics Interface Dictionary.
Exploded Pie Chart Generated with the DSGI
shows a pie chart that was created entirely with DSGI functions. Text Slide Created Using the DSGI is an example of a text
slide that was created with DSGI statements.
Exploded Pie Chart Generated with the DSGI
Text Slide Created Using the DSGI
DSGI uses GASK routines
and functions to draw graphics elements. These statements have the following
syntax:
CALL GASK(operator, arguments);
|
return-code-variable=function-name
(operator, arguments);
|
where
arguments |
are the additional required variables
or values for the routine or function. |
return-code-variable |
is an arbitrary name and can be any
numeric variable name. It will hold the return code upon execution of the
function. |
function-name |
is the DSGI command you want to execute
and must be one of the following: GDRAW, GINIT, GPRINT, GRAPH, GSET, or GTERM. |
operator |
is a character string that names
the function you either want to submit or for which you want the current settings.
When used with functions, operator can take different values
depending on function-name. |
When using
DSGI statements,
the following formats for arguments must be used:
- All x and y coordinates
are expressed in units of the current window system. (See The Current Window System for details.)
- The arguments
used with DSGI functions can be
expressed as either constants or variables. The arguments used with GASK routines
must be variable names since values are returned through them. See DATA Step Graphics Interface Dictionary for a complete explanation
of each argument used with DSGI functions and routines.
- All arguments that are character constants must
be enclosed in either single or double quotation marks.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.