How to move name and measure in vtkMRMLAnnotationRulerNode

Development
1

Hi guys,

I have created a new scripted module that uses two rulers to do measure airways and veins on a CT image.

I know the rulers’ name and measure are automatically placed next to the Ruler. However, many times these are on the way and make the measure difficult.

Do you know a way to make them selectable (I don’t see any appropriate function in the three display nodes of the rulers), so that they can be moved away when needed?

Thanks a lot,
Pietro

2

Hi Pietro,

It is not possible to directly move the text around. That said, as illustrated below, you could change the visibility, opacity or scale of the text.

annotations-edit
annotations-edit1440×851 326 KB

3

Hi JC,

thanks for your reply! OK, I see. And there is a way in python to at least remove the measure and just leave the name next to the ruler? Setting opacity to 0 removes both name and measure, but I need the name next to the ruler.

Thanks a lot,
Pietro

4

Do you mean displaying only 41.7mm instead of M: 41.7mm ?

5

Nope, the other way around, displaying only M instead of M: 41.7mm.

6

It is not currently possible to selectively display one or the other.

The code responsible for formatting the “name: value” string can be found here:

and here:

To achieve you describe, the annotation would have to be updated.

7

We had a similar need in SlicerIGT extension’s BreachWarning module. We ended up creating a string with custom content and set it as node name. If this does not work for you then submit a feature request at https://issues.slicer.org/ .

8

In the Modify Annotation properties pop up for the ruler, under Advanced,
Lines, you can move the position of the text along the ruler, from 0 at one
point to 1 at the other end point. From python:
displayNode = ruler.GetDisplayNode()
print displayNode.GetLabelPosition()
displayNode.SetLabelPosition(0.8)
So you’d have to set up a slider similar to the Label Position slider in
your module if you wanted to have a GUI interface to it.

The label format got over written when the Units code was integrated, the
ruler.Get/SetDistanceAnnotationFormat calls are there but the settings are
ignored by the annotation ruler displayable manager in GetLabelFormat.

Nicole