I use the HDMI to connect my Droid4 to a projector. I want to project documents that are in Portrait orientation. HDMI is normally a landscape format. I can readily turn my projector on its side so that the projected output appears to be portrait.
The Droid is not so accommodating. If I hold the phone in portrait orientation, I can see my whole document on the phone. However, the image of the phone on the projector only occupies the middle third of the screen (since it is displaying the portrait image of the phone in the middle of the landscape HDMI field.) This results in low image quality. If I rotate the phone, the phone's video out automatically uses the entire HDMI display area which is great. However, it also rotates my document on the phone screen so that it too is in landscape, and I only see the top third of the document.
Here's what I want: I want to have the display on my phone in portrait orientation. I then want to have it rotated for the HDMI output. If I were to put it on my TV, it would appear as if I had taken a picture of my portrait phone and turned it sideways. It would fill up the entire HDMI space with a nice high resolution image, but sideways. Now I take my projector and rotate it 90 degrees and voila, I have a portrait HDMI projection.
It is a bit confusing to describe, but I hope this makes sense. Simply locking the rotation on the phone doesn't work because then turning the phone from portrait to landscape does not rotate the phone screen (good), but it will also not rotate the hdmi output (bad). I also tried making my source document a PDF and rotating it 90 degrees. This works great on my computer screen, but the Droid4 is "too smart" and automatically corrects the orientation for me. Boo.