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I use Ubuntu Natty, urxvt (with 256 colours), and Imagemagick (display -window root [...]) to set the root window to a picture. When I use the transparancy (-tr) option on urxvt, I get the Ubuntu X login screen background (The pink/purple one) and not the image that is currently on the root window. See picture at the bottom.

Note that the same problem exists if I run gnome-terminal and set its transparency.

I suspect that imagemagick is not drawing on the right X11 layer but I (and google) cannot figure out what the right option is.

Could the problem be with either the xorg configuration or with window composition?

enter image description here

Edit: Added a bounty since either no one is interested or no one knows...

Finally, here is the full command I use in debug mode:

$ display -window root -geometry '-0-0' -resize '1920x1080>' -debug X11 /media/MediaVault/Images/Wallpapers//347852_1257250176_large.jpg
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeStandardColormap/8206/X11
  Standard Colormap:
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeStandardColormap/8207/X11
    colormap id: 0x20
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeStandardColormap/8209/X11
    red, green, blue max: 255 255 255
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeStandardColormap/8212/X11
    red, green, blue mult: 65536 256 1
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5588/X11
  XImage:
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5589/X11
    width, height: 1200x717
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5591/X11
    format: 2
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5593/X11
    byte order: 0
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5595/X11
    bitmap unit, bit order, pad: 32 0 32
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5598/X11
    depth: 24
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5600/X11
    bytes per line: 4800
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5602/X11
    bits per pixel: 32
2011-08-24T15:47:49+01:00 0:00.070 0.060u 6.6.2 X11 display[8318]: xwindow.c/XMakeImage/5604/X11
    red, green, blue masks: 0xff0000 0xff00 0xff
2011-08-24T15:47:49+01:00 0:00.090 0.070u 6.6.2 X11 display[8318]: xwindow.c/XMakePixmap/7548/X11
  Pixmap:
2011-08-24T15:47:49+01:00 0:00.090 0.070u 6.6.2 X11 display[8318]: xwindow.c/XMakePixmap/7549/X11
    width, height: 1200x717
2011-08-24T15:47:49+01:00 0:00.090 0.070u 6.6.2 X11 display[8318]: display.c/XDisplayBackgroundImage/13735/X11
  Image: /media/MediaVault/Images/Wallpapers//347852_1257250176_large.jpg[0] 1200x717
2011-08-24T15:47:49+01:00 0:00.090 0.070u 6.6.2 X11 display[8318]: display.c/XDisplayBackgroundImage/13741/X11
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Clearly this is a hard problem no one knows the answer to... –  Sardathrion Aug 23 '11 at 7:46
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2 Answers

If you do tail the syslog and grep for X, does it show any potential errors?

sudo tail /var/log/syslog | grep X

I am not that familiar with Imagemagick, but if I was in the same position I would definitely check out the config files for it and make sure everything is sounds (vars pointed properly, etc).

Try turning on debugging for imagemagick as well ( -debug X11).

http://www.imagemagick.org/script/command-line-options.php#debug

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No error messages in either syslog or Xorg.0.log. I suspect that display (from imagemagick) sets a different root window from what is assumed to be the real root window as seen by urxvt. If I use feh to set the wallpaper, transparency works fine. However, I'd rather use display so I can position my wallpaper where I want it and resize images that do not fit within my monitor. –  Sardathrion Aug 24 '11 at 14:29
    
What occurs when enabling imagemagick debugging? –  Ray Aug 24 '11 at 14:40
    
Debugging option and full command line dded to question. –  Sardathrion Aug 24 '11 at 14:50
    
before you used Imagemagick to overlay the background image on your desktop, was the default background the same as the one shown in the screenshot? I believe Imagemagick layers your specified image on top of the existing background, which is why the transparency is acting this way. I'm doing some more digging, I think there may be a way to set gnome to only use the input from Imagemagick as the root window background (without overlay). –  Ray Aug 24 '11 at 15:26
    
Yes, it is the pink ubuntu one. BTW, I use fvwm2 and not gnome. I am ancient school. –  Sardathrion Aug 24 '11 at 15:36
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I use feh to accomplish this and it works on debian and ubuntu with windowmaker and wterm(rxvt base):

https://wiki.archlinux.org/index.php/Feh#As_a_desktop_wallpaper_manager

Excerpt:

When using GNOME, you must disable Nautilus from controlling the desktop. The easiest way is to run this command: 
$ gconftool-2 --set /apps/nautilus/preferences/show_desktop --type boolean false

I'd be curious if that helps, since it sounds like the issue isn't with the background itself in X, but some other silly gnome tool(really, ancient school yet using gnome?! ;)

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Sadly this made no difference. Could it be that gdm is messing with things? –  Sardathrion Aug 27 '11 at 10:41
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