Xft Hack Improves Antialiased Font Rendering

Eugenia writes: "Font antialiasing first made its way to XFree through Qt/KDE only a year ago and GTK+/Gnome followed some time after. Even with the latest version of Freetype 2.08, which reportedly brings better quality, the result is still not up to par with the rendering quality found on some commercial OSes. David Chester has hacked through the Xft library and he achieved an incredibly good quality on antialias rendering under XFree86. With this hack, at last, XFree can deliver similar aesthetic results to Mac OS X's or Windows' rendering engines. Check the two brand-new screenshots ('before' and 'after') at his web page and notice the difference with your own eyes."

Comments

that's something completely different

[markj02]

Computer text is usually rendered onto a solid color and displayed on a high-quality, high-bandwidth device. That has almost nothing to do with rendering text for overlay onto a pictorial background and display on a low-pass, noisy device like broadcast television. Rendering text for GUIs the way you render it for television would be like slapping people in the face to get their attention and just would drive them crazy.

Anti-aliasing for computer displays is overrated anyway. Whether it helps or hurts readability depends on the font and font size, and on high resolution displays it is pointless. Printed matter isn't anti-aliased either, and printed matter is the gold standard for good looking text.

So, if you want text that looks nice, get yourself a 150dpi or higher monitor and don't bother with anti-aliasing. Anything else is a kludge.

Re:Font rendering in the X server

[kcbrown]

Look, my comment is in no way a criticism of RENDER. I can see lots of advantages to having that extension, and it's excellent work.

What I'm talking about is fonts, and only fonts.

Antialiased text might be an interesting and cool use of the RENDER extension, but it's not a particularly good use, and here's why:

1. Every toolkit for which you want antialiased text must be compiled with Xft support (or whatever client-side font handler supports the RENDER extension).
2. Every client machine on which you're running an X application must not only have the above mentioned toolkits, but must also have a set of fonts to be used by the client.
3. You now have to concern yourself with whether or not the fonts are all the same on all of the client machines you're going to use.
4. If you want to use a font on multiple clients, you have to install it on all of those clients, instead of simply sticking it on the font server.
5. Since there's no guarantee that the X server supports the RENDER extension, every client (or toolkit that the client uses -- this could be included in Xft, for instance) has to have fallback code which uses the standard X font calls in case the RENDER extension is unavailable. But this is a big problem, because now you have to concern yourself with whether your font metrics (among other things) for your standard server-side fonts are the same as the ones for the fonts on the client, since the font set being used by the X server is different than the font set being used by the client.
6. Proprietary toolkits and clients (particularly those that are statically linked) gain no benefit at all -- they use non-antialiased fonts as usual.
7. All the world isn't Unix, you know. What are you going to do about those X clients that are running on systems on which your toolkits won't even compile (VMS comes to mind, outdated as it may be)? X isn't just supposed to be network-based, it's supposed to be platform independent, but this method of font handling is anything but.

The end result that I see is that client side font rendering doesn't give you any real advantages over server side rendering, with the sole exception (that I can think of, at any rate) that the client will know that the font being displayed on the screen and the font being used for printing will have the same metrics and appearance. Other than that, you take a performance hit (client has to upload the font to the server every time it wants to use it, the same font will be uploaded multiple times by multiple clients or at least multiple toolkits, since it's possible for the toolkit to cache the font locally in shared memory or something. I'm making certain assumptions about the implementation here, though), you get inconsistent font handling and rendering (what says that toolkit A will use the same font set as toolkit B?), you'll probably use a lot more in the way of server resources if you're running clients on lots of different machines, and worst of all your desktop looks really inconsistent. The only time you don't really run into most of this is when the client and server are on the same machine. While I'll admit that this is most of the time, if you're going to give up some of the advantages of a networked display system why stop there?

It seems to me that this way of handling fonts does exactly the same thing for fonts that client-side GUI toolkits does for look and feel: causes a ton of confusion, makes it difficult to get a consistent look and feel on the desktop, and causes a lot of waste in the process.

So the bottom line is that, as far as I can see, what we really need is the RENDER extension and server-side antialiased font handling. (We also need server-side toolkits, but that's a discussion for another day).