Forum Discussion

coopdaddyswag's avatar
coopdaddyswag
Binge Watcher
7 years ago

Ability to Dim the Roku's Screen?

I am investigating a potential feature to my application which I can programmatically dim the brightness of the screen. I get I will not be able to change the brightness of the TV but I was wondering if:


  1. If there are any objects available in the SDK that provide that functionality? To dim the screen.

  2. Or, I was thinking of potentially creating an overlay, with a set color and opacity that would have a higher z-index? I was thinking if you use a view or you use a roBitmap to create a drawing and set it to the size of the visible screen.

Thanks
Roku Developer Program
  • squirreltown's avatar
    squirreltown
    Roku Guru
    7 years ago
    1. No.
    2. You can certainly do this, but It doesn't look like a dimmed screen, it looks like you put something over it.
  • NB_'s avatar
    NB_
    Roku Guru
    7 years ago
    "squirreltown" wrote:
    2. You can certainly do this, but It doesn't look like a dimmed screen, it looks like you put something over it.

    why not? cover it with black at certain alpha and that will darken the screen, no?
    talking w/o thought much but seems doable. since linear may not play well with gamma correction but if i try to imagine in what way, best i can get is prolly a headache 😄
  • coopdaddyswag's avatar
    coopdaddyswag
    Binge Watcher
    7 years ago
    I think it would be nice to have the ability to, but I think I may give it a shot - #2. I guess it doesn’t hurt to try.

    I’m just looking for a black overlay with a set alpha value. As an idea, I can see it working, but that’s different when you actually implement it haha!

    My screensaver is a simple black background with all white text and icons. If anything, I need it to dim the readable text and icons. I think it should work in my case.

    I’ll report back after I try this out.
  • squirreltown's avatar
    squirreltown
    Roku Guru
    7 years ago
    "RokuNB" wrote:
    "squirreltown" wrote:
    2. You can certainly do this, but It doesn't look like a dimmed screen, it looks like you put something over it.

    why not? cover it with black at certain alpha and that will darken the screen, no?
    talking w/o thought much but seems doable. since linear may not play well with gamma correction but if i try to imagine in what way, best i can get is prolly a headache  ðŸ˜„

    To me a "dimmed screen" is an actual thing, that you've seen on your laptop or phone or whatever. It's accomplished by reducing the brightness of the backlight. It looks very much different than putting a transparent grey layer on top of the image. If that's OK then fine, but that wasn't the question asked.
  • NB_'s avatar
    NB_
    Roku Guru
    7 years ago
    "squirreltown" wrote:
    To me a "dimmed screen" is an actual thing, that you've seen on your laptop or phone or whatever. It's accomplished by reducing the brightness of the backlight. It looks very much different than putting a transparent grey layer on top of the image. If that's OK then fine, but that wasn't the question asked.

    oh yeah, i don't think that can be done - not from STB over HDMI anyway. But does it matter if screen can be dimmed down to "TV black", even if backlight is still blasting full behind LCD screen? (in case of local dimming on LED-backlit screens that may turn down the lights - and with OLED that'd be true dimming)
  • coopdaddyswag's avatar
    coopdaddyswag
    Binge Watcher
    7 years ago
    I was able to get a working version of a dimmed screen. As the thread has mentioned, there is no way to actually dim the TV's screen. That makes sense and I totally get that, however, I wanted to see if adding an overlay could artificially dim the colors of my screensaver on the screen. The TV screen backlight stays the same brightness but after adding the overlay, I can see a noticeable effect "artificially".

    By using the z-index, I added a new rectangle object to the screen, added a transition and size, with a color with an opacity level. Here are results:



    Obviously, these pictures do not show the physical brightness of the screen but it did lower the apparent brightness of the white. Give it a try!