Thanks for the information.
Actually what I have in my table are three different fields, the first two are coming each from a different data source, the 3rd one is a calculated field (Difference between the two).
In this case I was not able to apply the information in the link you sent me.
1. Write one more calculated filed on top of your 3rd column to define negative and positive outcome and Name that calculated field as "Result"
observe the below example
2. Now click on the Dimension you required , then select 'Text Tables' in show me control.
3. change its style from 'Automatic' to 'Shape' in Marks card
3. Now drag the calculated field Result (as per my example) to 'Shape' in marks card, then it will automatically adjust for negative and positive default shapes.
4. You can now Edit shapes as per your requirement.
Please try and let me know if this is helpful.