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drevicko
Asked: 2012-12-20 19:08:49 +0800 CST

`xcalib -i -a` controls only one of two screens - can it control both?

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I am using 2 screens, and wish to invert the colors on both of them without using compiz (I'm using gnome shell).

I can use xcalib -invert -alter as suggested in this question, but it only inverts one of the screens. Is there a way to specify both of them, or even which of them, using xcalib? Is there another way?

With xcalib, you can specify which screen to alter with the -d (-display) or -s (-screen) options, but alas, X seems to be aware of just one screen: when I use the w command I only see one (the usual ":0")

ps: this question was originally posted by k0pernikus as a comment here.

---edit---

This is the output of xrandr:

Screen 0: minimum 320 x 200, current 3200 x 1200, maximum 8192 x 8192
VGA-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
1280x1024 60.0*+ 75.0
1280x960 60.0
1152x864 75.0
1024x768 75.1 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 72.8 75.0 66.7 60.0
720x400 70.1
DVI-0 connected 1920x1200+1280+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 60.0*+
1600x1200 60.0
1280x1024 75.0 60.0
1280x960 60.0
1152x864 75.0
1024x768 75.1 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 72.8 75.0 66.7 60.0
720x400 70.1

I can use -s DVI-0 or -s VGA-0, but they do the same as -s :0

xorg

3 Answers

  1. No.

    Note that as of date of last testing (2014, xcalib version 0.8) xcalib has not been able to invert the colors on all monitors in a multi-monitor setup, because all monitors are presented by the X11 server as a single screen. Thus this limitation is coming from the X11 server. xrandr-invert-colors does not have this limitation, because it uses XRandR API, which correctly handles all attached monitors.

    from here: https://github.com/zoltanp/xrandr-invert-colors

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  2. The display ids in X follow the form :<screen>.<display>. Contrary to intuition, all the monitors in a multiple-monitor setup share a <screen>, but have varying <display>. The screen "first" in the setup is :0.0, and others are :0.1, :0.2, etc. The final command is xcalib -invert -alter -display :0.1

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  3. xcalib's -screen parameter takes the zero based integer index of the screen, ie, in your case 0 for VGA-0 and 1 for DVI-0.

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