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On-the-fly graph generation is useful for dynamic content web sites and automatic report generation. Ploticus is suitable for these situations since it is a non-interactive command line tool with a relatively small code size.
Prefabs may be used, or your plots can be script-based. With scripts, variables
are often passed in via the command line. It is also possible to have your
program build a ploticus script on the fly.
Direct CGI mode
One option for producing dynamic web content is to invoke ploticus in
direct cgi mode.
Within an <img> tag, specify a URL that invokes ploticus
with the desired parameters.
Using a ploticus-enabled dynamic content systemAnother option is to use a new package called Midriff which generates HTML pages dynamically (similarly to php or asp). Ploticus scripts or prefab invocations can be embedded directly within page templates for building dynamic graphs. To try this, build the ploticus API (see Makefile_api), then download midriff and build it with the ploticus option.Invoking pl via the shellThis is appropriate if you are using a dynamic web content system such as PHP, or invoking pl via cron or some other automatic command issuer. Generally the procedure is:
Troubleshooting tipsIn CGI contexts anything written to standard error is unavailable. Use the -diagfile stdout command line option to see diagnostic messages. Version 2.11+ offers the -echo stdout command line option which can be used during debugging to display evaluated script lines. |
![]() data display engine Copyright Steve Grubb ![]() |