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I don't think there's anything stopping an X server from doing per-window alpha blending, by simply letting the client know that it is never obscured. I'm not sure why none of the servrers do this, and application-based fake blending (like rxvt, konsole, and others) just looks stupid.

As for lower-level aplha blending, it may require a new extension, which is one of the nicer facilities of the X protocol.. The X Render extension may be enough.

They don't (or at least it depends what you mean with hardware rendered, as anything is hardware rendered).

Hardware 3D stuff is already there including network transparency through GLX
and 2D alpha-transparency is provided by the XRender extension.

Network transparency just means, that you have to have the possibility of doing remote calls (in one way or another) without being actually aware of it. It doesn't mean, that all calls have to be done over the network. The network is transparent (in other words invisible) to the application. That is what abstraction is for.

The app makes a call "Draw text with 50% transparency at X,Y". The underlying system makes a local function call, which, depending on the current situation, might or might not translate in to marshalling of the call, transporting it over the net, unmarshalling at the client, who might or might not use the graphics hardware in drawing the text.
Should the situation permit it, it could translate into a driver call, which draws the text directly by using the given hardware.

sure

http://www.eax.com :-)

The MITSHM documentation [reptiles.org] was written by Jonathan Corbet (of Linux Weekly News?) and Keith Packard in 1991. That's over 11 years ago! Is there a lack of good documentation because people are really too busy to write the documentation or is it because they do not want to write documentation?

Well, MITSHM is over 11 years old and there's little value in writing new instructions for MITSHM because there's nothing new to add. Some of the newer extensions have good documentation (eg, XRender).

But whether individual developers don't write documentation because they don't have time or simply don't want to is something I can't answer. I daresay it's a bit of both.

XRender is only for fonts. The translucent menus in KDE are a hack.


Not true. I suggest you check the Developers Guide to XRENDER before making false statements. Even a perfunctory glance at the screenshots on the page show alpha blended geometries other than fonts.

And I am quite sure for KDE 3.0.1 KDE->Control Center->Look and Feel->Style->Effects->Menu Translucency Type has an option for "XRender Blend". XRender, not just for fonts anymore.

FreeType is a software font engine that can be used in graphics libraries, display servers, font conversion tools, text image generation tools, etc. to produce high quality glyphs and characters. The important thing here is that FreeType supports Adobe Type1 and TrueType (that is, Windows) scalable fonts.

the X Rendering Extension is a protocol that represents a new way to render (that is, draw) stuff on your screen in X windows.

thus, Xft's incorporation into Mozilla gives us smooth, high quality, Windows compatible fonts while surfing the web on Linux or *BSD

Can someone *please* come up with a spec for overhauling font management in X? Overhauling X in general? Just steal display PDF from Apple/Adobe?

Xrender is an extension to the X protocol implemented in XFree86 that is resposible for the anti-aliasing in Qt/KDE. It supports Porter/Duff operations for image composition (true alpha blending) and elements found in DisplayPDF (paths, transformations, etc...). A good introduction to Xrender ideas and why the current X protocol was "blundered" are here. I especially like the part:

At one meeting, members of the X11 team looked around the table and discovered that not one of them had any clue about splines. Instead of doing something wrong, they left them out.

That pretty much sums up the hackery that is the X Window System.

The necessary support for this is in the XFree86 CVS already. There is a screenshot (check the Hello World! window) and the source code for this. Don't worry, Keith Packard has thought of everything. ;)

The necessary support for this is in the XFree86 CVS already. There is a screenshot (check the Hello World! window) and the source code for this. Don't worry, Keith Packard has thought of everything. ;)