OpenImageIO/oiio — pull request #679 by lgritz (2013-09-29 04:50:52+00:00)
Title: ImageBufAlgo::checker minor fixes

1. Fixed bug where the pattern was wrong when using nonzero offsets (got the math wrong for negative pixel coordinates relative to the offsets).

2. Change the function call so that it defaults to 0 for the offset values (you don't need to specify them explicitly).