Talk:Desktop Window Manager

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The Desktop Window Manager is a very interesting concept for most computer users who like graphical user interfaces with stunning views. And the DWM just offers that. Anyone with links for screenshots of some of the views can add them to this talk page. —The preceding unsigned comment was added by Annex (talk • contribs) .

Yeah, ok, it was here for AGES under Linux. Ignorant windows users, as always. 93.129.10.16 (talk) 09:36, 27 August 2012 (UTC)

General

The term Desktop Window Manager can be used also to Linux KDE, GNOME, XFCE and others. —Preceding unsigned comment added by 200.216.226.249 (talk) 16:58, 8 October 2009 (UTC)

Its not called "Desktop Window Manager", it is called "Window Manager". Those, who can do hardware 3D acceleration are called "Window Managers with composite functionality". Apparently, microsoft is very good at copying and reselling that - as always. 93.129.10.16 (talk) 09:36, 27 August 2012 (UTC)

XGL et al.

I'm finding it weird that XGL can have a reference to DWM, but DWM can't have a reference back to XGL. Why aren't XGL and Project Looking Glass considered relevent, but Mac OS X is?

Generally speaking, it's not good form to spend a good chunk of an article talking about what a subejct compares to, or to be a clearing-house of what other platforms offer. This article is sorely in need of more information on what the DWM -- a component of Vista -- actually is, and how it works. A section for XGL and Looking Glass doesn't contribute to the informational value of an article about the Vista DWM. The mention of Quartz isn't really all that great, either, but at least it's a point of reference that is familiar (and has been in a popular, shipping product for years). Ideally, all these different compositing engines would co-exist in a wikipedia Category, and we would have an article that generally describes the concept of DCE's as it applies equally to all platforms. We're not there yet, but it's going to have to come soon, given that every significant OS is going to have a DCE by default within a year's time, the way things are going. Warrens 21:10, 15 March 2006 (UTC)

XGL/Compiz

XGL isn't a window manager -- its a graphical system. Compiz is what handles windows in an xgl configuration. Fixed. --69.158.143.230 02:02, 15 August 2006 (UTC)

First Paragraph of Architecture

The first paragraph of the architecture section seems incorrect. It states that the offscreen buffers are in system memory but also that the GPU does the compositing, which seems to be a contradiction. It also says that the GPU does the rendering then in the very next sentence says that the CPU handles the rendering. I think it would be more correct to say that the offscreen buffer(s) are in virtualized video memory that WDM handles, and that WDM directs the GPU to composite the buffers together with the background and render to it's frame buffer. I list this in the discussion section only because I want someone to correct me if I'm wrong. -Doug

Could you please pick out the lines that suggests to you: "states that the offscreen buffers are in system memory but also that the GPU does the compositing, which seems to be a contradiction. It also says that the GPU does the rendering then in the very next sentence says that the CPU handles the rendering." Anyways, I read the architecture section, could not find anything wrong. Confusing, might be (thats why I am asking for the sentences). This is what happens when DWM is used:

Each application process renders the screen as a bitmap, which is stored on some off screen buffer. Each app to a different buffer. The reference says system memory, whether the system memory is due to being paged out from system memory or not, is not known. So, unless a reputed source says so, we cannot say they are in virtualized video memory.

Secondly the DWM process picks up the bitmaps from the per-app buffers periodically (as in several times a second). This DWM process runs independent of the application processes. It is DWM which then uses the GPU to string the bitmaps together and paints on screen. This compostition part is done on the GPU. How the application renders it to the offscreen buffers is of no concern to DWM or the composition process. It might use the CPU (GDI+) or the GPU (WPF) or pull it out of somebody's ass, DWM does not care. The only part WDM plays is that it allows DWM to access the buffers that are a part of some other process. --soum ^talk 08:29, 30 November 2007 (UTC)

Ok, that makes sense. However, if what you say is true, then there is alot of back and forth going on beteween system and video memory just to render a single frame. For example, take an application that uses WPF and thus the GPU for it's own application window. It must go to the video memory (to be handled by GPU), then be copied back to one of the system memory's back buffers, then copied back again with all the other back buffers into video memory by DWM so it can finally be rendered into the frame buffer. If that is the case, then the DWM way of rendering applications is incredibly inefficient for WPF applications, which considering they are the new way of doing things, should be efficient. -Doug

Things are a bit different for WPF apps. WPF apps, which are essentially DirectX apps, render to a in-video memory DirectX surface (the back buffer). By virtue of WDDM drivers in vista, this surface is shared with the DWM process. So, for DirectX apps, there is no concept of the intermediate buffer. (see the redirection secn for both GDI and DX redirection procedure). Note that by video memory I am also referring to video memory contents paged out to system memory (as the paging is transparent to applications). This special mode of handling surfaces is only for DirectX. Thats why OpenGL apps natively perform very badly in Vista. However, if the graphics cards drivers implement surface sharing inside the driver (without any assistance from DWM), the problem is resolved. Thats how ATI and NVidia provide high performance OpenGL implementation. --soum ^talk 05:20, 16 December 2007 (UTC)

Thumbnail public API

Quoting the article: "Windows Flip 3D uses the thumbnail APIs to get the window representations as bitmaps, and then uses that as texture for 2D rectangles,". This contradict MSDN as far as I can tell: "Note: DWM thumbnails do not enable developers to create applications like the Windows Vista Flip3D (WINKEY-TAB) feature. Thumbnails are rendered directly to the destination window in 2-D" —Preceding unsigned comment added by 129.241.129.157 (talk) 18:56, 8 December 2007 (UTC)

Bump: The reference cited in the article is not relevant to the statement.

References

Article Not Encyclopedic

This article reads too much like a technical manual. The average reader interested in the topic has no idea what it is saying. It needs to include at least more basic information. It needs to begin at the beginning. Technical info is fine, but here the reader is left without really knowing what Aero is. It should read more like an encyclopedia article.Randi75 (talk) 11:00, 22 February 2008 (UTC)

This is the article for the Desktop Window Manager -- Windows Aero is a seperate article. This article is rightly aimed at a more technical audience because it is on a technical topic: the engine behine Aero, rather than Aero itself. Similarly to how the Quartz Compositor article is much more technical than the Aqua (user interface) article. There is a clear link to Windows Aero in the introductory paragraph of this article for users who want the user interface details rather than the technical details. -- simxp (talk) 16:39, 21 April 2008 (UTC)

Important Information Needed

How does one turn the thing OFF? What will the effects be? —Preceding unsigned comment added by Mendori (talk • contribs) 02:47, 12 October 2008 (UTC)

Switch to the "Vista Basic" theme. -- simxp (talk) 14:13, 13 October 2008 (UTC)

Actually that does not switch DWM off, although it does disable most of its functionality. Disabling the 'Desktop Window Manager Session Manager' service switches DWM off entirely. The reason you might want to do that is that DWM interacts very badly with some applications, such as Thunderbird, when many windows are open, even in "Vista Basic" mode. --David-Sarah Hopwood ⚥ (talk) 02:36, 29 October 2009 (UTC)

Oh, and the effects are: your system runs slightly faster, with lower memory usage, and incompatibilities with some applications are fixed. --David-Sarah Hopwood ⚥ (talk) 02:39, 29 October 2009 (UTC)

How to resolve problems

The article is overly geek, and contains little that the average (or even a little above average) user needs. Wikipedia is surely not intended to simply ape technical manuals?

There really should be some info on problems and how to deal with them; there isn't even an indication of how to access control features.

The article is not just too technical; it is unhelpful. Heenan73 (talk) 11:25, 27 November 2011 (UTC)

Sharpe Shell

I like sharpe shell better. Way faster. 66.157.20.5 (talk) 19:00, 25 March 2009 (UTC)

Yes, they are doing a fine job supporting proprietary closed source system. So more people stay with it, instead of switching to much better systems that have dozens of WMs; not 1 official and 3-4 half-backed like Sharpe. Just keep on using Windows, be a good paying slave. 93.129.10.16 (talk) 09:40, 27 August 2012 (UTC)