3

I have an Android Wear watch face that I recently put on the Google Play store: https://play.google.com/store/apps/details?id=com.watchfuldesign.wearboy&hl=en

I recently got this review:

"Please add options to add a small day of month on the gameboy screen as well as not going black and white since that doesn't save battery for everyone."

Is that true? I had thought that by going black and white in ambient mode that it saves battery - is that not the case for particular devices?

I read the following on Android's Developer website:

"One reduced color space power saving method is to use a "low-bit" mode. In low-bit mode, the available colors are limited to black, white, blue, red, magenta, green, cyan, and yellow. When designing for low-bit ambient mode, use a black or a white background. For OLED screens, you must use a black background. Non-background pixels must be less than 10 percent of total pixels. You can use low-bit color for up to 5 percent of pixels on screens that support it." https://developer.android.com/design/wear/watchfaces.html#SpecialScreens

I believe that seems to contradict what the reviewer said but am not sure. Does anyone know exactly which modes should go BW and which ones don't need to for saving power?

(My watch face looks muuuuch better in color so I'd love to not make it BW in power saving mode - and it could really help my slumping sales!)

Thanks in advance!

trx25
  • 359
  • 3
  • 12
  • The second quote seems to imply it is the "non-background" (ie. non-black) pixels that defeat the minimized power savings.. which makes sense of [O]LED (as there is no universal back-light so black pixels are truly "off", although I have no idea how much this would affect overall power consumption). In any case I would expect any "on" pixels to take about the same amount of power for an equivalent luminosity - white, cyan, or otherwise. (Or the second quote could just be stating that nobody wants small black text on a magenta background Dx) – user2864740 Mar 03 '15 at 03:28

1 Answers1

4

Yes, it does. On different screens in different way.

Check out for example this article: http://blog.stevemould.com/phone-battery-save-black-wallpaper/ Full brightness of pixel on AMOLED uses 5.8 time battery than black pixel.

Sony Smartwatch uses transflective screen which power comes from reflecting light. But if it needs to actually brighten its pixels (no outside light) it uses even more power.

On top of that, for OLED screen you have to worry about burn-in, so you should always go into black and white and not use brighten too many pixels.

We gave these recommendations for a reason. Please adhere to them and we guarantee you will provide the best experience to your users (in terms of battery life, preserving screen and still maintaining good UI).

gruszczy
  • 40,948
  • 31
  • 128
  • 181
  • Thanks! That makes sense, I'll continue to adhere to the guidelines. – trx25 Mar 03 '15 at 15:40
  • Example is down. I have found out that for example moto 360 sport it does not consume significantly much more power. I cannot really measure this due to lack of software and skills I suppose but from every day normal use there is no apparent difference. – Jimmy Kane Jun 13 '16 at 17:47