Fonts specified in points are correctly rendered using the DPI setting correctly, as it has always been. So, as far as 99% of my work is concerned (terminals and text editors), there is no problem.

However GUI elements of most programs are still specified using pixels, so buttons, menus and some icons might look "tight" around the text if the theme is sized using pixels. Recent GTK/QT versions do support point units, so it mostly depends on the theme you choose. These toolkits also always (historically) had resizable dialogs, contrarily to window and mac, so even with "bad" support for high DPI, the text will be readable and the interface will be scalable.

Legacy apps, such as WindowMaker dockapps (which are historically sized as 64x64) though will be unreadable. Frankly, I can already cannot read them anymore.

Given the configurability of most programs, I would say it's really not a problem. Most of the other programs will be adapted very quickly.

Some basic support was introduced in Gnome 3.10 (and Gtk+) (http://www.phoronix.com/scan.php?page=news_item&px=MTQzMDY) thanks to some Chromebook Pixels donated by individuals and Intel (http://www.gnome.org/news/2013/07/gnome-receives-hardware-do...). After googling for about five seconds I found a review and the TL;DR is "it kinda works, but there are bugs" (like Windows, see http://keithcu.com/wordpress/?p=3270).

Never tried first hand, hope to have a chance with the Retina MacBook Pro I'm buying at the end of March.

KDE looked like this at the late 90's. Then they added settings for the default font size (or did I just find it by then?), and started improving. Now, with KDE 4, everything scales all the time, there aren't even many bitmaps anymore because they break in any kind of display.

But, yeah, a few applications can't deal with it.

Gnome 3.10 has it mostly right. I find there are less issues on Gnome than on Windows.

But then there's the problem when you open an app which is not native GTK/Gnome, for example Libre Office, where the fonts look OK but the icons are minuscule.

The Desktop itself and the Gnome applications look awesome on high DPIs.

Also Firefox works flawlessly, though on Linux you have to manually set the option "layout.css.devPixelsPerPx" on about:config.

I took a screenshot of the GIMP on 256 DPI: http://i.imgur.com/2GpqyND.png (XFCE4)

Well... X knows about dpi for ages. Unfortunately, people have been using pixel-based shortcuts for ages too for almost everything. The way Apple used to "fix" it is curious considering NeXT was, AFAIK, dpi-aware from the start.

Not very well. Chromium/Chrome is almost unusable, ditto for Skype. Firefox is ok, but many of the icons are quite small and hard to decipher, and you have to use NoSquint to make the pages readable. The Dev Tools are even worse.

Gnome terminal looks good though :) Many Gnome apps are fine, but Gnome 3 itself has problem.s

Openbox looks good on my Chromebook Pixel:

https://github-camo.global.ssl.fastly.net/52b6558796f033771c...

Elementary doesn't. They don't support high-DPI.

I had the same question. A 3200x1800 resolution on a laptop sounds wonderful!