Creating Custom Charts in Java

I am working on an application that required me to draw custom charts. This is what I was required to do: Draw a chart that consists of smaller graphs (which should each have tool tips) and the chart itself should be scrollable. This blog explains how this can be done and the problems I am facing.

This is what I had as a plan before I started coding,

1. For the chart, it has to extend JComponent, so that we can add the graphs to it and to make it scrollable depending on the number of graphs added.
2. The graphs too should extend JComponent so that we can have tool tips on them.

So the code came up something like this

The most important thing in this is to overload the getPreferredSize() method in the graph Component. If this is not done then the graph are given a default size of (0, 0) and the graphs don’t appear. So it’s important to calculate the size of the graph and return it in that method.
The main problem that I am facing is, in deciding the layout manager and the size of the graphs (which is being worked on).