iPhone dev Stupidity 90: SMS Balloon

Using [UIImage stretchableImageWithLeftCapWidth:topCapHeight:] to create the SMS balloon:

UIImage * img = [UIImage imageNamed: @"balloon.png"];

g_balloon_ = [[img stretchableImageWithLeftCapWidth: img.size.width/2 topCapHeight: img.size.height/2] retain];

assert(g_balloon_.leftCapWidth == (int)(img.size.width/2));

and the image looks like: