Dynamically change the Bar Chart width

[pumi_hasi]

Hi,

  I used iReport and jasper to create a bar chart which displays some graphical information depending on the user selection in the system.The number of bars in the bar chart get changed depending on the query results at each time.Being the defined chart width is a fixed value the bar width in the chart get changed each time.When there is only one bar in the chart, that bar is taking the full width from the chart width. So I want to dynamically change the chart width depending on the sql query results, or is there any way to keep the individual bar width fixed?

Thank You

Hasini

 

[dnvsrikanth]

Hi Hasini,

 

Even I had this problem previously in reports. I overcomed this issue by using Customizer class to customize the graph.

 

You need to know about the JFreeChart API to do this.

 

There is a sample delivered with the JasperReports distribution to demonstrate the customization. check the demo/samples folder in the JasperReports distribution.

 

DNV Srikanth

[sureshvarma]

Hi All,

I am facing the problem with bar chat design,how can i set the fixed width to the bars in bar chart.

Can any one give me the suggestion for over come this problem.

 

Thanks,

varma.

[svenn]

First the charting package does not allow you to set an absolute width. The best you can do is set a relative percentage width with respect to the total width of your chart.

To do this you have to create a customizer class as dnvsrikanth suggested.

In the customize method put the following code

if(jasperChart.getChartType() == JRChart.CHART_TYPE_BAR) {

                       

BarRenderer renderer = (BarRenderer) chart.getCategoryPlot().getRenderer();

 

//Set maximum bar width

renderer.setMaximumBarWidth(0.10);

           

}

 

[sureshvarma]

I dont know anything about customizer class,I am very new to this jasper.Can any one give the details about customizer class.Is there any chance provide the example customizer class.

Thanks in advance,

 

Varma.

[svenn]

If you have the professional version you can look at the samples provide with the distribution. Note that you have to have at least a basic understanding of java to do this.

Here's a example I found on the web

 

[rlfisherpbtgroup.com]

I solved this one by UNIONing my query with some fake rows (zero values) and a LIMIT clause so I would get the correct maximum number of rows - the last rows being zero length to fill out the width.

[mchisty]

 

 

Post Edited by mchisty at 07/13/2011 00:49

[mchisty]

I have a similar problem like yours. Could you please post your code fragment here? Really like to know how you solved it. Thanks.

[stlevkov]

 +svenn