Graphics Programs Reference
In-Depth Information
warning message about a nonexistent file the first time you run the script.)
You can also get extraneous output in a diary file if you type
CTRL+C
to halt a
script containing a
diary
command. If this happens, you should type
diary
off
in the Command Window before running the script again.
Presenting Graphics
As indicated in Chapters 1 and 2, graphics appear in a separate window. You
can print the current figure by selecting
File
:
Print...
in the graphics window.
Alternatively, the command
print
(without any arguments) causes the figure
in the current graphics window to be printed on your default printer. Since
you probably don't want to print the graphics every time you run a script, you
should not include a bare
print
statement in an M-file. Instead, you should
use a form of
print
that sends the output to a file. It is also helpful to give
reasonable titles to your figures and to insert
pause
statements into your
script so that viewers have a chance to see the figure before the rest of the
script executes. For example,
xx = 2*pi*(0:0.02:1);
plot(xx, sin(xx))
% Put a title on the figure.
title('Figure A: Sine Curve')
pause
% Store the graph in the file figureA.eps.
print -deps figureA
The form of
print
used in this script does not send anything to the printer.
Instead, it causes the current figure to be written to a file in the current
working directory called
figureA.eps
in Encapsulated PostScript
format.
This file can be printed later on a PostScript printer, or it can be imported into
another program that recognizes the EPS format. Type
help print
to see
how to save your graph in a variety of other formats that may be suitable for
your particular printer or application.
As a final example involving graphics, let's consider the problem of plotting
the functions sin(
x
), sin(2
x
), and sin(3
x
) on the same set of axes. This is a
typical example; we often want to plot several similar curves whose equations
depend on a parameter. Here is a script M-file solution to the problem:
echo on
% Define the x values.
x = 2*pi*(0:0.01:1);
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