Change the chart size dynamically

Hi All,
I have a small problem ,i am not able to change the size of the chart and the bar in the bar chart dynamically.

The only items that grow horizontally are matrix and chart. Some people have created reports with multple copies of the chart and had a flag that hid all but one of them. Also, custom report items will have the ability to grow dynamically. The width of the bars in the chart are determined based on the number of points.|||thanks for the reply
but how to grow the chart horizantally.