custom control where style changes depending on value

Hi,

I have to create a custom control. The requirement goes like this.

There should be a square with a horizontal line in the center. The consumer of this control
will send some negative (-) and positive (+) value to this control. If the value is negative
I have to show a colored,  kind of rectangle. below the horizontal line. This rectangle should increase and decrease depending
on the value. It means if the value sent by client is 2, the colored rectangle should be small, if 3 little
big and so on.
Similarly, if the value is positive, the colored rectangle should grow above the horizontal line.

Could you please tell which base control should be best for this. Also, can you please suggest some
idea how can I achieve this so that the control becomes very flexible for the consumer?

Thanks.