Another limitation--if you frequently connect an external display to your MacBook Pro--is that Pupil is optimized for a single display. On multiple-display setups, you must choose which display Pupil should control, and if you later want to change the resolution of the other display, you must first take a trip back to Pupil's preferences and tell it to control that display. Finally, Pupil doesn't provide any keyboard shortcuts--a deal killer for some users.
Louder Than Ten and Padraig Kennedy, who collaborated on Pupil, put some thought into the design of the app. It's convenient and pleasing to use, despite a few minor quirks. Retina MacBook Pro owners should have a screen resolution switching utility, and Pupil is one to consider. A 14-day demo of Pupil is available if you want to try before paying $5.
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