Add macos with_disallow_hidpi

[slmjkdbtl]

• Tested on all platforms changed
• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• Created an example program if it would help users understand this functionality

Implemented by gentz and tested myself on macOS, mimicing sdl's SDL_WINDOW_ALLOW_HIGHDPI flag

[goddessfreya]

r? @francesca64

[goddessfreya]

@slmjkdbtl Can you resolve the merge conflict?

r? @mtak-

[goddessfreya]

@Osspial can you just merge this? It's been a week.

[Osspial]

Sorry it took so long to respond to this!

I'm not sure I'm comfortable with exposing another platform-specific DPI override just for macOS. We've already got an override for X11, and I don't want to keep adding platform-specific ways of controlling winit's DPI support until we have several subtly different and incompatible ways to set DPI.

There's talk going on in #796 about the HiDPI API, and I'd like to see that conclude before we decide whether or not to merge this.

[goddessfreya]

@Osspial What's the verdict? I'd rather this gets merged.

[elinorbgr]

Just to be sure I get a clear image, what would be the consequence of this flag precisely?

[goddessfreya]

To quote the macos docs:

You can opt in to high resolution by calling the method setWantsBestResolutionOpenGLSurface: when you initialize the view, and supplying YES as an argument: [..] If you don’t opt in, the system magnifies the rendered results.

Basically, if you disable this flag, the window's size on the screen will stay the same, but it's contents will get magnified. This is unlike changing the dpi, which changes the window's size.

Maybe @slmjkdbtl can provide a screenshot?

[elinorbgr]

Ok, so This is the same as what a non-hidpi wayland app would do, so such a flag would be trivial to replicate on Wayland, and I guess it would only make sense on these platforms.

[goddessfreya]

@slmjkdbtl Could you quickly rebase this against the new master?

[Osspial]

FWIW, I'm going to rescind my objections to this.

We could also implement this on Windows, but it would be an EventLoop-level flag, not a Window-level flag.

[goddessfreya]

Hey, apologizes, but this PR has fallen greatly out of date. Could you rebase this against the new master and open a new PR. Anyways, I'm closing this one. Thanks.