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Comment by the_mitsuhiko | Hacker News Reader

> The major fundamental issues are there for Wayland too.

Which fundamental issues does Wayland have with DPI? I'm not aware of there being any fundamental issues with the DPI handling there.

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A quote from the article.

"If you think this idea is a bit stupid, shed a tear for the future of the display servers: this same mechanism is essentially how Wayland compositors —Wayland being the purported future replacement for X— cope with mixed-DPI setups."

A bit disingenuous to quote an outdated fact. Wayland has supported "proper" DPI (i.e. one without downscaling) for quite a while now, and it's been widely implemented across the ecosystem (on the server side: KDE, GNOME, wlroots-based compositors, Smithay-based compositors, on the client side: GTK, Qt, SDL).

That is only the fallback path in Wayland.

aw I thought one of the advantages of Wayland is better DPI scaling

now where did I hear that, many years ago..

sad that corporate interests (or wetf) are blocking X11 updates, though I don't trust the quality of Xlibre given the regressions the dev introduced previously

was planning to go back to Sway once I finally get a 4K monitor..

I think the fundamental design flaw with the scale all screens approach that wayland(and mac and X11 when set that way) employs is that your application is unable to have better dpi aware rendering. however that may actually be an advantage because it means your application does not need a better dpi aware rendering engine, that is things just work everywhere, it may look theoretically worse in it's scaled context, but at least the application writer does not have to do anything so everything just works.

The fundamental issue that it's a hard problem (no matter if on X11/Wayland/Windows/Mac), which can only be solved by the apps and toolkits themselves.

It's only a hard problem if you want to make it one. Mac and Wayland have a pretty elegant and simple solution that does not complicate things. There is nothing wrong at rendering at higher DPI and scaling down. But that's not the problem with X11, the problems there are deeper as explained in the comment I referenced.

There's nothing wrong with OS level down-scaling? Can you show examples screenshots and videos of this? I will assume that

- it will require a lot more memory for cached textures etc. since these are created in a virtualized pixel space - it will look more blurry and wrong, most importantly the text will be less than crisp.

Apart from that, in many situations you have to scale _up_. Try any older random Windows application (that hasn't declared "DpiAwareness"), even older Windows system dialogs, on a HiDpi monitor (say 27" 4K which is about ~163dpi). They get up-scaled by the system and they look _bad_.

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