I have an iPad 3rd gen and a MacBook Air 13" (mid 2013). I am using the software "Air Display" to connect the iPad as a second screen. So far so good. The thing is, since it's a retina display, it goes by default into that resolution, whereas I would like to have a HiDPI resolution, given that a 9" screen is not comfortabe otherwise.
So I just go to System preferences and change the resolution. And it's done.
The thing is, I connect and disconnect the iPad loads of times, and every time I have to repeat the procedure. I contacted Air Display support to ask if they could help me set HiDPI as default and they replied with this:
Thanks for contacting us with your questions about Air Display and glad to hear that you are enjoying Air Display.
Currently we are unable to get the HiDPI resolution to be remembered by OS X as it's hidden by default. This means that if you wish to use this mode you'll have to switch to this resolution manually each time. We are still trying to determine if we can find a workaround to fix this but are hoping we can resolve the problem. We apologize for the inconvenience in the meantime.
If you have any other questions please feel free to ask. I'd be happy to answer them for you.
Avatron Software, Inc.
That being said, is there a way to do this with Automator? Or with an applescript that I leave on my desktop and double click every time I connect the display. I'm not that familiar with Apple systems, but it seems like a reasonable task to be able to automate or "semi-automate".