Hi ! 
  
I think that I ask is not possible but I try  
  
I want to do multiplications and divisions with macros of annotations. 
  
For exemple here the JSFiddle : 
http://jsfiddle.net/x5FBh/620/ 
  
I try to put the green circle (last annotation in code) in the center of the canvas, how can I do that ? 
I tried like the JSFiddle exemple : $canvasStartX + ($canvasWidth / 2) 
But the ($canvasWidth / 2) is ignored, when i remove brackets / 2 is ignored. 
  
Do you have any other solution for me ? 
Keep in mind the chart is dynamically resized, so fixed values don't work. 
  
  
Thank you, 
Sébastien