More evidence of iOS 10 'dark mode' emerges, hints at cellular toggle in Control Center
Further explorations of iOS 10's code may back expectations that the mobile OS will get a "dark mode" in later betas, and/or a cellular connection toggle in its Control Center.
New screenshots show the operating system's hidden "dark mode" working in the Settings app, according to a recent Twitter post by developer Andrew Wiik. That would support speculation that Apple is planning to offer system-wide support, rather than implement app-specific options akin to iBooks.
Wiik was the source of recent screenshots of Messages running in the new mode. Prior to that, various AppleInsider readers noted that asking Siri to turn on dark mode resulted in the assistant saying it's "not able to change that setting," instead of offering a generic response.
Wiik also recently posted a shot of the iOS 10 Simulator with a sixth, blank button near the top of the Control Center. While its purpose is uncertain, Wiik speculated that Apple might be planning a cellular toggle.
iOS 9's Control Center includes options for toggling Wi-Fi, or killing all wireless connections via Airplane Mode, but not a way of just halting cellular data -- something useful when 3G/4G connections are weak or a person is trying to avoid roaming and data cap penalties. At the moment, iOS 9 users have to delve into the Settings app to stop cellular without also affecting Wi-Fi and Bluetooth.
At the moment iOS 10 exists only as a developer beta. A public beta is due in July, followed by an official release in the fall -- most likely in September for new iPhones.


Comments
Just put your phone in airplane mode, then click again on wifi. The cellular remains off. That's it.
this also blocks any incoming/outgoing calls and texts. not the same.
Your airplane explanation is kind of like if someone walked up to me and went "Dude, my iPhone makes loud sounds, I dunno wot to do w it" and I answer "Yeah, fill a bathtub and throw it in, that'll make sure it won't make those sounds anymore".
What happens when you visit a website with a white background?
I would much rather prefer a VPN on/off toggle up there over some "cellular data off" function that hardly anyone would use. And there is already a battery saving function (Low Power Mode), so perhaps it'll be a toggle for that instead. I've never switched off cellular data and I know of no one who does.
Other screen shots I've seen of the iOS 10 Control Center have been lacking the center "Night Shift" toggle in the bottom row. It's conceivable that they may relocate it to the top row.
It will work across the OS and in Apple's core Apps. 3rd party Apps, probably as part of AutoLayout, will have to adopt support for it.
But people are always talking about getting blasted with bright light while in bed. Dark mode solves that.
Except... visiting site like AppleInsider and others with white backgrounds. That's why I was curious.
It would just need some different rules as night mode wouldn't invert dark into light and it shouldn't invert images/videos at all, there would just be some contrast adjustment. In addition to invert in Accessibility, a proper dark mode would be better for people with light sensitivity and contrast controls that don't make an image negative for people with poor eyesight.
There's a Mac utility called Shades:
http://www.charcoaldesign.co.uk/shades
That adds an additional brightness slider to the Mac system. This is good for people with light sensitivity but it doesn't retain low-level detail due to reducing contrast.
The night mode for images/videos can use the brightest parts of an image as a mask. Then have an adjustment curve to pull down the brightest parts by half and then pull the mid-levels down further to bring back some contrast. This keeps the black levels as they were originally so that detail doesn't get clamped and it just compresses the brightest parts:
Inverted mode is top middle, which makes the image unrecognizable and is for people who just want to see shapes moving. In the adjusted images, the dark objects like the bag and dress retain the brightness level but the brightest parts of the image become darker. There can be additional saturation correction and there's an edge filter added in these images to enhance the contrast.
There are night mode apps for jailbroken iOS but they don't always make the right choices on what to make dark:
When it comes to UI elements vs images/videos, they'd invert colors that were above a certain luminance level and then check the contrast level between those changed elements and the surrounding ones. Applying the above adjustments to a UI results in the following middle image:
It would be easier to deal with in the dark than the normal view and is easy to keep consistent but it lacks contrast. The right image would be better.
The changes can be specified by the developer on a per-app basis to make sure it looks right but this would just override an automatic mode that can do a decent job of lowering the brightness. To get to that image on the right, they'd highlight everything that was over 50% luminance and invert the luminance value but keep the hues and saturation the same. Inverting the luminance values in a single pass of the calendar results in the following:
They'd check the contrast between the surrounding elements (difference in luminance) of small elements and if they found that the contrast was too low, they'd undo the inversion for those elements. In the case of the calendar, the contrast of the red can switch back to the original because the original red has higher contrast. The light grey would also go back to the original.
The sequence would go:
UI elements: check how many pixels above a certain luminance value are on the page and invert their luminance if there's a lot (don't invert already dark pages). Then check the contrast of small elements and invert their luminance if the contrast is too low.
images/videos: compress brightest parts of images, retain black levels, correct saturation, optionally enhance edges
developer override: specify special UI options for dark mode
This makes the work less for developers because auto dark mode might do a pretty good job and only mess up one or two buttons. This means they don't have to theme an entire dark mode, they'd just specify dark mode elements to use for the elements that don't look right.
The downside to auto filtering would be extra processing while in dark mode but it's unavoidable with images and videos. There is no way to manually set dark mode for images and video content. The processing should be minimal for the UI as it's just flipping over the luminance values based on how much of the UI those colors take up. They have to look out for composited values though because when elements are anti-aliased, the edges would use the original colors so they'd either change it before compositing or make further adjustments.