acornejo/jquery-cropbox — pull request #5 by KidkArolis (2014-01-30 12:19:18+00:00)
Title: Fix getBlob, getDataURL when image isn't dragged

Initialize the top (and left) to 0px - otherwise top is undefined if the image isn't dragged. This causes a NaN to be passed into context.drawImage in getDataURL and results in a transparent png being returned by canvas.toDataURL().