Adding an Annotation to a Category Chart

Ignition
1

I found a way to do it here :

viewtopic.php?f=70&t=6402&p=18059&hilit=xytextAnnotation#p18059

Unfortunately I am not very familiar with java and am having a tough time navigating the jfreechart API to do the same thing with a category chart.

Could someone point me in the right direction?

Thanks,

Mike

2

You would do something similar but use the category text annotation:from org.jfree.chart.annotations import CategoryTextAnnotation chart = event.source.parent.getComponent("Chart") plot = chart.getChart().getCategoryPlot() plot.addAnnotation(CategoryTextAnnotation("Hello World", "Category", 25.0))

3

Thanks. This worked.

I am confused though because the categoryItemRenderer had nothing about addAnnotation(). addAnnotation only appears under Interface XYItemRenderer.

4

The categoryItemRenderer isn’t the object being used to add the annotation. The CategoryPlot object returned by the chart.getChart().getCategoryPlot() is what has the addAnnotation() method.

5

I tried to extend this to change the font/color of the Annotation and i’m running into some syntax errors.

[code]from org.jfree.chart.annotations import CategoryTextAnnotation
chart = event.source.parent.getComponent(“Chart”)
plot = chart.getChart().getCategoryPlot()
from java.util import Date

data = system.dataset.toPyDataSet(event.source.parent.getComponent(‘Chart’).Data)
for row in data:
a1 = CategoryTextAnnotation((“Hours: %s” % row[1]), row[0], 1.02)
a1.setFont(Font(‘Courier New’, Font.ITALIC, 12))
plot.addAnnotation(a1)
[/code]

NameError: name ‘Font’ is not defined

I seem to be missing something here, help? :slight_smile:

6

Looks like you forgot to import Font:

from java.awt import Font
7

Ohh it is always the little things…

Thanks James

8

AttributeError: 'org.jfree.chart.renderer.category.LineAndShapeRend' object has no attribute 'addAnnotation'

9

That is explained above.