What is the optimal size for a control page on an iPad 3 so that no rescaling need take place?

We've documented control page sizes for the various iOS devices in this wiki article. For the retina display enabled devices (iPhone 4/4S, iPad 2012), you can double the size of the control page and the resolution of any images you supply and Indigo will scale them to fit - which will then cause the images to look as good as possible. Note, however, that the built-in images don't have 2x versions so they'll all look half the size. So if you want to make a retina-enabled control page you'll need to provide all the images yourself.

Control pages that use the pre-retina iPad size indicated above will continue to look pretty much exactly as they did before.

OK, then optimal landscape mode on the iPad 3 is 2048×1408 ... correct?

Probably. I haven't personally tested it but that should be right.

Doesn' work for portrait ...

Actually ... those dimensions are correct for landscape, but not in reverse for portrait. Very odd. Will figure out dimensions in portrait and post.

For some reason, when in Portrait mode optimal size is 1408w x 1776h. However, Landscape is 2048w x 1408h.

Here is a test control page on the iPad3 at 1408w x 1776h in portrait ... no scaling and no scrolling. For some reason, any bigger on the height or width and the entire page is not displayed thus causing you to scroll to see it all. Any smaller, and Indigo has to upscale it to fill the screen.

pwfletcher wrote:For some reason, when in Portrait mode optimal size is 1408w x 1776h. However, Landscape is 2048w x 1408h.

Thanks for posting - I'll update the wiki page with the info.