This samples shows how you can extend ArcObjects to build a new custom textbackground. ArcMap ships with
several textbackgrounds including: Balloon Callout, Line Callout, Marker Text Background, and Simple Line Callout.
This new textbackground is a Circle Line Callout and it is very similar to the Balloon callout except, like its name
suggests, it is circle and for simplicity sake, its leader line is just a straight line. The image below shows an example:
How to use:
Register the dll.
Add TextCallouts.PropertyPage to the 'Text Background Property Pages' component category.
Add TextCallouts.CircleCallout to the 'Text Backgrounds' component category.
Add a text element onto your map.
Right-click on the selected element and select 'Properties' from the context menu.
Select 'Change Symbol'.
Select the 'Advanced Text' tab.
Click on 'Text Background', then select its related 'Properties' button.
In 'Type', select 'Circle Line Callout'.
Its property sheet is displayed and from here you can set its size and color.
Hit 'OK' on all subsequent dialogs to get back to ArcMap.