Great app, definitely gonna add it to my list of must haves for this phone.
One thing however, using MHL requires you be plugged in to the AC charger no? That's 2A not .5A. So even with the screen on, this phones beastly wall charger should put out enough power to charge the phone pretty much no matter what you do with it.
That being said I will still most definitely get this app for my HDMI-out usages. Thanks
Update: downloaded it and sure enough my suspicions were confirmed. After reading in the description how it "turns off the backlight" I had a feeling I knew what was going to happen.
The app doesn't actually turn the display off. The screen is still on, it's just displaying full black. Tested it in a dark room, you can see a slight glow coming from the screen, and pressing the power button causes a substantial drop in darkness to pitch black, meaning screen turned off. So the real question is, what type of impact will this have on battery life, and furthermore does it have any impact on the performance hit we take by doing HDMI mirroring. It obviously takes more GPU power to send an image to 2 displays instead of 1, so I wonder how this really works compared to actually turning the display off. Does the app just place a full black image over our screen, giving the illusion the screen is off? Or does it actually kill all screen draw processing on the GPU, causing an increase in not only battery life but in frame processing performance.
I'll have to wait till I get my MHL adapter to play around with it, probably try running a Quadrant Advanced with both Mirrored HDMI and with this app running, note any differences, and draw conclusions from there.