Trying to create a histogram with ZedGraph

Question

Hello,

I am trying to create a histogram with ZedGraph.

The bars and data are all good, the only thing needed is I would like my bars to be between tics instead of directly on tics.

Sample data :

1, 4
2, 8
3, 1

means that I have :

4 items that are <= 0 and < 1
8 items that are <= 1 and < 2
1 item that is <= 2 and < 3

So currently my bars are of course appearing directly on the tics (x values) 1, 2 and 3.

But I would like to see : the first bar between the tics 0 and 1, the second bar between the tics 1 and 2 and the third bar between the tics 2 and 3

Does anybody know the property to tweak in order to achieve that? I am currently looking in XAxis and XAxis.Scale but found nothing yet...

Answer 1

You probably can't do it with normal BarItem. I use the BoxObj objects to create the histogram.

If histList is the PointPairList containing your pairs of histogram values (breakpoint and value) you can use:

for (int i = 0; i < histList.Count - 1; i++)
{
BoxObj box = new BoxObj(histList[i].X, histList[i].Y, histList[i + 1].X - histList[i].X, histList[i].Y);
box.IsClippedToChartRect = true;
box.Fill.Color = myColor;
pane.GraphObjList.Add(box);
}

Using the BoxObj you have full control on where the bar is located etc. More info in documentation

EDIT
Remember that when using BoxObj (or any GraphObj in general) the X and Y scales are not going to be set automatically. You need to set the scale ranges manually:

pane.XAxis.Scale.Min = ...
pane.XAxis.Scale.Max = ...
pane.YAxis.Scale.Min = ...
pane.YAxis.Scale.Max = ...