objective c - NSTableView with chat bubbles -

i need create nstableview chat bubbles messages app. there sample code/tutorial can use.

i trying use view based nstableview, custom nstablecellview. added background image , trying use following code stretch chat bubble:

 nsimage *backgroundimage = [nsimage imagenamed:@"background"]; backgroundimage = [backgroundimage stretchableimagewithleftcapwidth:10.0f topcapheight:22.0f]; self.backgroundimageview.image = backgroundimage; 

i following mcimage category https://github.com/drewmccormack/backtothemac, image not getting stretched.