Written by Ian on 26/08/08
I needed a PHP page that would select some data from a whole bunch of files, and then plot it online.
• Although there are many possible ways of doing this, all of them are really clunky and difficult.
So then I
• looked around and found a really excellent tool: Open Flash Chart (OFC).
• This is open source (free) software.
• You just download a few libraries, drop them into the root directory of your webserver - any webserver as far as I can see - then edit some of the examples to produce really amazing graphics.
Check out this one here.
It uses a prebuilt flash executable that simple plays back the graph image. You get to write the graph by making a data file in a JSON format (a standard format). Even better to know is that the author of this OFC gives you the tools to make a JSON file.
I won't spend time here by writing examples, because you can find extensive and useful tutorials on the OFC webpages.
• What I will do though is give you some hints and tips:
1. Go for OFC2.
• It's still in late alpha, but is probably more consistent than OFC and will be developed for longer.
2. If you plot a scatter plot (because you don't have sequential points along the x-axis) then you will find that there is a problem with the x lables. To get around this, create the graph as normal, and then use specific commands to set the x-axis attributes:
this is from one of the code snippets on the OFC website.
• You have already, somewhere, created an x-axis called $x, and now you create a x-labels object:
Then you apply attributes as required:
Then you apply these x-labels with their attributes into the already existing x-axis:
Finally you create the chart as normal (i.e. as in all the examples).
3. You can't (as far as I can see) change the colour and the size of the labels on the y-axis (unless you add a y-axis to the right hand side of the graph), so just keep the x-axis ones as black 10 point text!
• Now you can have great-looking graphs on your website, thanks to the developes of OFC.