NAME
Apache::GD::Graph - Generate Charts in an Apache handler.
SYNOPSIS
In httpd.conf:
PerlModule Apache::GD::Graph
SetHandler perl-script
PerlHandler Apache::GD::Graph
# These are optional.
PerlSetVar Expires 30 # days.
PerlSetVar CacheSize 5242880 # 5 megs.
PerlSetVar ImageType png
# The default image type that graphs should be.
# png is default, gif requires <= GD 1.19.
# Any type supported by the installed version of GD will work.
PerlSetVar JpegQuality 75 # 0 to 100
# Best not to specify this one and let GD figure it out.
Then send requests to:
`http://www.server.com/chart?type=lines&x_labels=[1st,2nd,3rd,4t
h,5th]&data1=[1,2,3,4,5]&data2=[6,7,8,9,10]&dclrs=[blue,yellow,g
reen]'
INSTALLATION
Like any other CPAN module, if you are not familiar with CPAN
modules, see:
http://www.cpan.org/doc/manual/html/pod/perlmodinstall.html .
DESCRIPTION
The primary purpose of this module is to allow a very easy to
use, lightweight and fast charting capability for static pages,
dynamic pages and CGI scripts, with the chart creation process
abstracted and placed on any server.
For example, embedding a pie chart can be as simple as:
And it gets cached both server side, and along any proxies to
the client, and on the client's browser cache. Not to mention,
chart generation is very fast.
Graphs Without Axes
To generate a graph without any axes, do not specify x_labels
and append `y_number_format=""' to your query. Eg.
http://www.some-server.com/chart?data1=[1,2,3,4,5]&y_number_format=""
Implementation
This module is implemented as a simple Apache mod_perl handler
that generates and returns a png format graph (using Martien
Verbruggen's GD::Graph module) based on the arguments passed in
via a query string. It responds with the content-type
"image/png" (or whatever is set via `PerlSetVar ImageType'), and
sends a Expires: header of 30 days (or whatever is set via
`PerlSetVar Expires', or expires in the query string, in days)
ahead.
In addition, it keeps a server-side cache in the file system
using DeWitt Clinton's File::Cache module, whose size can be
specified via `PerlSetVar CacheSize' in bytes.
OPTIONS
type Type of graph to generate, can be lines, bars, points,
linespoints, area, mixed, pie. For a description of
these, see the GD::Graph(3) manpage. Can also be one of
the 3d types if GD::Graph3d is installed, or anything
else with prefix GD::Graph::.
width Width of graph in pixels, 400 by default.
height Height of graph in pixels, 300 by default.
expires Date of Expires header from now, in days. Same as
`PerlSetVar Expires'.
image_type
Same as `PerlSetVar ImageType'. "png" by default, but
can be anything supported by GD.
If not specified via this option or in the config file,
the image type can also be deduced from a single value
in the 'Accepts' header of the request.
jpeg_quality
Same as `PerlSetVar JpegQuality'. A number from 0 to 100
that determines the jpeg quality and the size. If not
set at all, the GD library will determine the optimal
setting. Changing this value doesn't seem to do much as
far as line graphs go, but YMMV.
cache Boolean value which determines whether or not the image will
get cached server-side (for client-side caching, use the
"expires" parameter). It is true (1) by default. Setting
`PerlSetVar CacheSize 0' in the config file will achieve
the same affect as `cache=0' in the query string.
For the following, look at the plot method in the GD::Graph(3)
manpage.
x_labels
Labels used on the X axis, the first array given to the
plot method of GD::Graph. If unspecified or undef, no
labels will be drawn.
dataN Values to plot, where N is a number starting with 1. Can be
given any number of times with N increasing.
ALL OTHER OPTIONS are passed as a hash to the GD::Graph set
method using the following rules for the values:
undef Becomes a real undef.
[one,two,3]
Becomes an array reference.
{one,1,two,2}
Becomes a hash reference.
http://somewhere/file.png
Is pulled into a file and the file name is passed to the
respective option. (Can be any scheme besides http://
that LWP::Simple supports.)
[undef,something,undef] or {key,undef}
You can create an array or hash with undefs.
['foo',bar] or 'baz' or {'key','value'}
Single and double quoted strings are supported, either
as singleton values or inside arrays and hashes.
Nested arrays/hashes are not supported at this time, let
me know if you need them for some reason.
AUTHOR
Rafael Kitover (caelum@debian.org)
COPYRIGHT
This program is Copyright (c) 2000 by Rafael Kitover. This
program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
ACKNOWLEDGEMENTS
This module owes its existance, obviously, to the availability
of the wonderful GD::Graph module from Martien Verbruggen
.
Thanks to my employer, marketingmoney.com, for allowing me to
work on projects as free software.
Thanks to Vivek Khera (khera@kciLink.com) and Scott Holdren
for the bug fixes.
BUGS
Probably a few.
TODO
If possible, a comprehensive test suite. Make it faster?
SEE ALSO
the perl manpage, the GD::Graph manpage, the GD manpage