It's easy to write an app that displays arbitrary graphics at 1600 nits on the MacBook Pro. You just have to use the Metal API, an "extended" color space, and a Float colorPixelFormat.
I'm not sure that this blog post author is trying to accomplish, possibly they are trying to use some other API besides Metal?
I’m not trying to draw HDR content. I want to increase to overall UI brightness (basically, make the brightness of where backlight LEDs go past the software defined limit)
I’m testing Apple’s claim of 1000 nits sustained brightness which led many people to believe that they can finally use their laptop in direct sunlight without squinting at the screen.
I’m aware of thermal limitations and that even sustained might not mean “whole screen at 1000 nits for 8 hours”. But it would be nice to be able to use 1 hour of my work time to work in the park outside my apartment with a bright enough screen for that time.
The system has thermal capping implemented from what I saw in the CoreBrightness framework, so it should be safe as long as the system can detect that LEDs are starting to overheat and lower the brightness automatically.
As a suggestion to help you with your quest - try polarised sunglasses. I used them with my M1 mac this summer quite successfully! The macbook screen is polarised so that the screen light goes straight through the sunglasses, while the surrounding sunlight gets dimmed.
"Vertically polarized light is preferentially refracted at the surface, so that the reflected light is left more horizontally polarized" and you use vertically polarised sunglasses to filter out the reflected horizontally polarised light.
> I’m testing Apple’s claim of 1000 nits sustained brightness which led many people to believe that they can finally use their laptop in direct sunlight without squinting at the screen.
Well yes, even that would be useful if working with text. (although I’m sure some will also be doing some graphic work)
But this can’t be done either. That website has the whiter-than-white text because it chose to do that. It’s known that every app has the possibility of rendering HDR content at more than 500 nits.
The problem I was trying to solve is how to do that from the outside, on apps that haven’t implemented HDR logic (which is about all of them)
The author is the author of lunar - https://lunar.fyi/ - an app for controlling screen brightness on external (and internal) screens on the Mac. He is trying to force the system to brighten the entire screen to the levels it will brighten light spots in an HDR video.
Heh, interesting. When I just got my new macbook, I did try to draw something with a "whiter than white" color to see what the display is capable of. But I didn't think of Metal, I poked around in a custom NSView with various NSColor constructors passing values more than 1, and that didn't work.
I'm not sure that this blog post author is trying to accomplish, possibly they are trying to use some other API besides Metal?