Prima(3) User Contributed Perl Documentation Prima(3)NAME
PDL::Demos::Prima - PDL demo for PDL::Graphics::Prima
SYNOPSIS
You can enjoy this demo in any number of ways. First, you can invoke
the demo from the command line by saying
perl -MPDL::Demos::Prima
Second, you can invoke the demo from with the pdl shell by saying
pdl> demo prima
Finally, all of the content is in the pod documentation, so you can
simply read this, though it won't be quite so interactive. :-)
perldoc PDL::Demos::Prima
podview PDL::Demos::Prima
DESCRIPTION
The documentation in this module is meant to give a short, hands-on
introduction to PDL::Graphics::Prima, a plotting library written on top
of the Prima GUI toolkit.
use PDL::Graphics::Prima::Simple
To get started, you will want to use PDL::Graphics::Prima::Simple. This
module provides a set of friendly wrappers for simple, first-cut data
visualization. PDL::Graphics::Prima, the underlying library, is a
general-purpose 2D plotting library built as a widget in the Prima GUI
toolkit, but we don't need the full functionality for the purposes of
this demo.
use PDL::Graphics::Prima::Simple;
my $x = sequence(100)/10;
line_plot($x, $x->sin);
More than just lines!
In addition to numerous ways to plot x/y data, you can also plot
distributions and images. The best run-down of the simple plotting
routines can be found in the Synopsis for PDL::Graphics::Prima::Simple.
$distribution = grandom(100);
hist_plot($distribution);
$x = sequence(100)/10;
cross_plot($x, $x->sin);
$image = rvals(100, 100);
matrix_plot($image);
Mouse Interaction
Plots allow for mouse interaction, herein referred to as twiddling. You
can resize the window, zoom with the scroll wheel, or click and drag
the canvas around. There is also a right-click zoom-rectangle, and a
right-click context menu.
hist_plot(grandom(100));
# Run this, then try using your mouse
In your Perl scripts, and in the PDL shell for some operating systems
and some versions of Term::ReadLine, twiddling will cause your script
to pause when you create a new plot. To resume your script or return
execution to the shell, either close the window or press 'q'.
# If your PDL shell supports simultaneous
# input and plot interaction, running this
# should display both plots simultaneously:
$x = sequence(100)/10;
cross_plot($x, $x->sin);
line_plot($x, $x->cos);
Multiple plots without blocking
The blocking behavior just discussed is due to what is called
autotwiddling. To turn this off, simply send a boolean false value to
auto_twiddle. Then, be sure to invoke twiddling when you're done
creating your plots.
auto_twiddle(0);
hist_plot(grandom(100));
matrix_plot(rvals(100, 100));
twiddle();
Once turned off, autotwiddling will remain off until you turn it back
on.
# autotwiddling still off
hist_plot(grandom(100));
matrix_plot(rvals(100, 100));
twiddle();
Adding a title and axis labels
Functions like hist_plot, cross_plot, and matrix_plot actually create
and return plot objects which you can subsequently modify. For example,
adding a title and axis labels are pretty easy. For titles, you call
the title method on the plot object. For axis labels, you call the
label method on the axis objects.
# Make sure autotwiddling is off in your script
auto_twiddle(0);
# Build the plot
my $x = sequence(100)/10;
my $plot = line_plot($x, $x->sin);
# Add the title and labels
$plot->title('Harmonic Oscillator');
$plot->x->label('Time [s]');
$plot->y->label('Displacement [cm]');
# Manually twiddle once everything is finished
twiddle();
Saving to a file
PDL::Graphics::Prima::Simple excels at user interaction, but you can
save your plots to a file using save_to_file or save_to_postscript
methods, or by right-clicking and selecting the appropriate menu
option.
auto_twiddle(0);
$x = sequence(100)/10;
line_plot($x, $x->sin)->save_to_postscript;
# You can supply a filename to the method if you like.
# Also available is save_to_file, which saves to raster
# file formats. Expect save_to_postscript to be merged
# into save_to_file in the future.
Adding additional data to the plot
Once you have created a plot, you can add additional data to it. You
achieve this by adding a new DataSet with the data you want displayed.
auto_twiddle(0);
my $plot = hist_plot(grandom(100));
# Add a Gaussian curve that "fits" the data
use PDL::Constants qw(PI);
my $fit_xs = zeroes(100)->xlinvals(-2, 2);
my $fit_ys = exp(-$fit_xs**2 / 2) / sqrt(2*PI);
$plot->dataSets->{fit_curve} = ds::Pair($fit_xs, $fit_ys);
twiddle();
The default plot type for pairwise data is Diamonds. You can choose a
different pairwise plot type, or even mix and match multiple pairwise
plot types.
auto_twiddle(0);
my $plot = hist_plot(grandom(100));
# Add a Gaussian curve that "fits" the data
use PDL::Constants qw(PI);
my $fit_xs = zeroes(200)->xlinvals(-5, 5);
my $fit_ys = exp(-$fit_xs**2 / 2) / sqrt(2*PI);
$plot->dataSets->{fit_curve} = ds::Pair($fit_xs, $fit_ys,
# Use lines
plotTypes => [
ppair::Lines(
# with a thickness of three pixels
lineWidth => 3,
# And the color red
color => cl::LightRed,
),
ppair::Diamonds,
],
);
twiddle();
The plot command
If you want to specify everything in one command, you can use the plot
function. This lets you put everything together that we've already
discussed, including multiple DataSets in a single command, title
specification, and x and y axis options.
# Generate some data:
my $xs = sequence(100)/10 + 0.1;
my $ys = $xs->sin + $xs->grandom / 10;
my $y_err = $ys->grandom/10;
# Plot the data and the fit
plot(
-data => ds::Pair($xs, $ys,
plotTypes => [
ppair::Triangles(filled => 1),
ppair::ErrorBars(y_err => $y_err),
],
),
-fit => ds::Func(\&PDL::sin,
lineWidth => 3,
color => cl::LightRed,
),
-note => ds::Note(
pnote::Text('Incoming Signal',
x => 0.2,
y => sin(0.2) . '-3em',
),
),
title => 'Noisey Sine Wave',
x => {
label => 'Time [s]',
scaling => sc::Log,
},
y => { label => 'Measurement [Amp]' },
);
Enjoy PDL::Graphics::Prima!
I hope you've enjoyed the tour, and I hope you find
PDL::Graphics::Prima to be a useful plotting tool!
# Thanks!
AUTHOR
David Mertens "dcmertens.perl@gmail.com"
LICENSE AND COPYRIGHT
Copyright (c) 2013, David Mertens. All righs reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.
perl v5.18.1 2013-05-12 Prima(3)
