Wayland Protocol Finally Ready for Fractional Scaling

Post by WhyNotHugo » Mon, Nov 28, 2022, 9:21 AM UTC

Sakos wrote: post #48

WhyNotHugo wrote: post #41

Earlier quoted context omitted.

> For example, my favorite screenshot tool supports automatic timed screenshots, of particular windows or the whole screen or of a specified region, of one desktop or several, and various customizations. Those features aren't supported by my compositor, and I don't have a choice. So Wayland limits my options. Xorg doesn't support his either. Your screenshotting tool runs the timer and takes the screenshot when the ti…

> Xorg doesn't support his either. Your screenshotting tool runs the timer and takes the screenshot when the timer expires. You complaint is like saying "the Linux kernel won't render markdown for me". No, it won't, you're looking at the wrong part of the stack. Xorg also doesn't prevent you from using an application that does have these functions. Wayland does prevent you. > but it's perfectly possible to write with…

I you feel so strongly about missing features, I suggest you report the issue and propose and approaches to it. Complaining on HN that "there's functionality missing" won't change anything.

I believe that the only thing missing is capturing individual windows with screencopy. There's actually an issue for that and ongoing discussion on how to implement it. Nobody's decided it's a bad idea, it's simply a matter of nobody having done it so far.

Xorg never "implemented" this feature. It's just that any client can read what other clients are doing. So Skype can screen-scrape your password manager by default. Obviously this was not a good choice, so Wayland has dedicated protocols for this functionality, with the intent of restricting them only to privileged clients.

Finally, while no _standard_ protocol exists to address this, there are compositor specific ways of capturing a single window, so most users have their needs met.

Post by chrismorgan » Mon, Nov 28, 2022, 1:10 PM UTC

qyron wrote: post #75

chrismorgan wrote: post #21

Earlier quoted context omitted.

On the specific topic here, fractional scaling, macOS gets it disastrously wrong, only supporting downscaling, which means that it’s impossible to get pixel-perfect output on fractional scales, which are the norm on most of their devices. I seriously can’t comprehend how they ended up going that way, given that they were the ones in a position to force developers to get things right, far more than Windows, but no, th…

I don't really know how HiDPI is implemented on Windows, but I do know some very popular VST plugins (music production software, which usually uses its own GUI and scaling integration) which still doesn't scale properly in popular plugin hosts, so you can't really talk about "getting it right in all circumstances". This problem doesn't exist on Mac where the OS is kind of responsible for all the scaling. So, between…

That’s a different matter.

Firstly, your VST situation will be that the plugin, the host or both are not implementing things correctly: one or the other has claimed DPI-awareness inappropriately. That’s on them.

Secondly, you misunderstand the relative situations of macOS and Windows. The difference is not to do with their approach to scaling, but rather their approach to supporting old software, and the diversity of hardware. Social factors, not technical. Apple could absolutely have done fractional scaling, and it’d have worked just fine for them; the present situation in how well high-DPI stuff works across platforms would be indistinguishable: macOS would still have basically nothing broken, and Windows would still have quite a few widely-used pieces of software getting it wrong. Here’s why:

Apple developers are very probably using a high-DPI screen, so they’ll immediately notice if anything is off. Apple is controlling, and anything published through their store will have any obviously-bad scaling noticed and rejected. Apple doesn’t care about long-term compatibility, so earlier software that didn’t implement scaling properly largely just doesn’t run at all any more.

Windows developers are probably using a low-DPI screen, and are publishing to a largely unmoderated platform that still has software from decades ago run just fine.

Functionally there’s no difference between fractional and integral scaling in how well software will support them. If you try to implement things completely from scratch, fractional will be a little harder because you have more rounding decisions, but in practice you always use a library that takes care of that for you (normally a full widget toolkit, but VST plugins will often use something somewhat lower-level but still above the physical-pixels layer except when you deliberately opt for fine control), so there is literally no difference at all. The difference in how well things work on these different platforms is purely other factors.

Re: Wayland Protocol Finally Ready for Fractional Scaling

Re: Wayland Protocol Finally Ready for Fractional Scaling