"Ambient mode" brought up-to-date with the launcher branch

[andre]

I'm keeping the Ambient mode branch current for use in my own cabinet ...

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Why and What

The intent of Ambient Mode is to allow your arcade cabinet to assume a low-key presence in a room. For example, in a living room setting, you might not want the cabinet to be a focal point all the time. Ambient Mode allows the cabinet to recede to the background without powering it all the way off.

It's basically a screensaver that is activated by the exit button (but "screensaver" nomenclature is already utilized in the project).

When enabled:

• the "exit" controller combo button from the RetroFE main menu will go to ambient mode instead of exiting RetroFE.
• while in ambient mode, images from the "ambient" directory will be displayed on the main screen, and rotated periodically
• to exit ambient mode, the controller combo button OR the action button will return you to the main RetroFE menu.

Configuration

1. create a directory called "ambient" in the same directory as the RetroFE executable, and populate it with images.
   If you have a 2nd monitor, you should have at least one image name ending with "_marquee.png" (or any other common image extension)

2. in settings.conf:

    controllerComboExit = false
    controllerComboAmbient = true
    ambientModeMinutesPerImage = 30 # OPTIONAL - how often to change to a new image. 

Marquee display

If you have two monitors, the second monitor is assumed to be a marquee display. When a new image is displayed on the main screen, the corresponding marquee image will be displayed if it exists, by looking for "*_marquee.ext". For example, if "sunset.png" is being displayed on the main screen, the system will look for "sunset_marquee.png" to display on the marquee.
If no corresponding marquee image is found, a random marquee image is displayed instead.