shifting bars or range label

Is there a way to shift the bars in the histogram graph to make it look more like a histogram or change the x-axis's scales' labels?

The label that I am getting is a set of x-axis scales (in CDateTime format), so it is something like 07/ 28 05:00, 7/28 10:00, 7/28 15:00, 7/28 20:00. I have already gotten the frequencies for the time range, and I would like to make it look like a histogram rather than a bar graph. I can either set the scales' label to a set of ranges (07/ 28 00:00 - 07/ 28 05:00, 07/ 28 05:00 - 7/28 10:00, etc) or insert a beginning scale label with no value and shift all the bars to the left.

Again, attached is what my graph currently looks like.

Code snippet:

xAxis = chart.getPrimaryBaseAxes()[0];
xAxis.getLabel().getCaption().getFont().setRotation(45);
// xAxis.setLabelPosition(Position.RIGHT_LITERAL); //error
xAxis.setGapWidth(10); //??
xAxis.getTitle().getCaption().setValue("Time");
xAxis.getTitle().getCaption().setColor(ColorDefinitionImpl.CREAM());
xAxis.getTitle().setVisible(true);
String k=xAxis.getLabel().getCaption().getValue();
System.out.println("Value: "+k); -->print out "Value: " no k value?

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Comments

JasonW

Are you just wanting to remove the space between the bars?

You can do this by setting the unit spacing on the chart:
cwaBar.setUnitSpacing(1);

Jason

markcheung

The space does not really matter. I would like to insert an initial value as the starting point for the histogram. It would have no correspondance on my dataset . Then shift the bars to the left to make it looks like a histogram rather than a bargraph (something likes this: <a class='bbc_url' href='http://media.techtarget.com/digitalguide/images/Misc/iw_histogram.gif'>http://media.techtarget.com/digitalguide/images/Misc/iw_histogram.gif</a> ).<br />
<br />
Right now it is something likes <a class='bbc_url' href='http://www.neuroscience.com/bargraph.gif'>http://www.neuroscience.com/bargraph.gif</a>.

JasonW

Would adding to the dataset do what you want? Take a look at the attached example which adds a value to the beginning and end of the chart using the afterDatasetFilledScript.

Jason

markcheung

ok, attached is what I have.

Is there a way to shift the bars to the left (with BIRT Chart Engine), so they will illustratively shows that it is a histogram and not a bar graph. (such that the labels would be at the sides of the bars, rather than the center).

JasonW

You can set a script using the api. Try a script something like the following:
cwaBar.setScript("function beforeDrawSeries( series, seriesRenderer, context )"
+"{if( series.getSeriesIdentifier() == "Series 1" ){"
+"var dpharray = seriesRenderer.getSeriesRenderingHints().getDataPoints();"
+"for( j=0;j<dpharray.length;j++){"
+"var xval = dpharray[j].getLocation().getX();"
+"dpharray[j].getLocation().setX(xval-30);}}}");

Make sure to set the identifier for the bar series like:

bs.setSeriesIdentifier("Series 1");

Jason

markcheung

Worked perfectly. Thanks!