GTK Theme is not being followed by all GTK Applications (on LXDE)

On my LXDE (Ubuntu Oneiric 11.10) setup, I have recently discovered that not all GTK applications are getting themed with the GTK theme (Adwaita) of my preference. 

My first obvious attempt was to reset theme with LXDE Menu > Preferences > Customize Look and Feel. I set Adwaita in the "Gadget" tab. That Didn't help. Many "sudo" applications along with some other normal GTK-3.0 applications (e.g. evince) stills stayed un-themed.


Ubuntu repository apparently has two tools to set GTK-2.0 themes:

1. gtk-chtheme
2. gtk-theme-switch

Gtk-chtheme is much better in my opinion. So, I gave it a shot and selected "Adwaita" from the list of installed GTK theme. Still no change.

Then as a last resort, I wanted check which GTK theme files are actually being accessed during the initialization of the applications. For that, I started Evince from the console with strace as below:

strace -e trace=access evince 2>&1 | less

After a quick checking through the output it was obvious that my GTK-3.0 themes are not being found by the applications and the theme files are being searched for both in:

1. /home/USER-NAME/gtk-3.0
2. /home/USER-NAME/.config/gtk-3.0

On Ubuntu, GTK themes are installed in /usr/share/themes. So, the quick, easy and clean solution to the problem was to create a sym-link to the GTK-3.0 theme of my preference as shown below:

ln -s /usr/share/themes/THEME-NAME/gtk-3.0 /home/USER-NAME/gtk-3.0

ln -s /usr/share/themes/THEME-NAME/gtk-3.0 /home/USER-NAME/.config/gtk-3.0

After creating the sym-links, I restarted Evince and voila! it's perfectly themed with Adwaita now.


P.S.
If you ware selecting another themes other than Adwaita, make sure /usr/share/themes/THEME-NAME/gtk-3.0 actually exists. Not all themes in /usr/share/themes/ are GTK-3.0 compatible and they will miss the gtk-3.0 directory inside the theme folder.

Compile NS-2.34 and 2.35 with GCC-4.6

I stumbled into the compilation issue after upgrading to Ubuntu Oneiric 11.10. The error occurs in "mac-802_11Ext.h" saying something like the following:

mac/mac-802_11Ext.h: In member function 'u_int32_t PHY_MIBExt::getHdrLen11()':mac/mac-802_11Ext.h:175:19: error: expected primary-expression before 'struct'mac/mac-802_11Ext.h:175:41: error: 'dh_body' was not declared in this scopemac/mac-802_11Ext.h:175:51: error: 'offsetof' was not declared in this scope

I found the solution in Ubuntu's patched version of NS-2.35-RC6. The direct link to the patch is here: http://launchpadlibrarian.net/74445224/ns2_2.35~RC6-4_2.35~RC6-4ubuntu1.diff.gz

It's really simple. All you have to do is to add #include cstddef as shown below:

#ifndef ns_mac_80211Ext_h
#define ns_mac_80211Ext_h
#include cstddef
#include "marshall.h"
#include "timer-handler.h"

 Now, NS-2.34 should compile fine with GCC-4.6. Enjoy your simulation!

P.S. BlogSpot is simply terrible for posting code snippets. For clarity, here's a screenshot of what the code should look like.

 

Google Chrome (Chromium) font anti-aliasing is wrong on LXDE (L)Ubuntu Oneiric (11.10)

The solution was to add the following in the ~/.fonts.conf 

• https://gist.github.com/1318856

xml version="1.0"?>DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
 <match target="font">
  <edit mode="assign" name="rgba">
   <const>noneconst>
  edit>
 match>
 <match target="font">
  <edit mode="assign" name="hinting">
   <bool>truebool>
  edit>
 match>
 <match target="font">
  <edit mode="assign" name="hintstyle">
   <const>hintslightconst>
  edit>
 match>
 <match target="font">
  <edit mode="assign" name="antialias">
   <bool>truebool>
  edit>
 match>
 <match target="font">
   <edit mode="assign" name="lcdfilter">
    <const>lcddefaultconst>
   <edit>
 <match>
</fontconfig>

One may have to play around with the "hintstyle" to get it right. The available options are:

• hintslight
• hintmedium
• hintfull
• none

Ubuntu Oneiric (11.10) DPKG error removing old Linux kernel

I stumbled into another trouble removing my obsolete packages after upgrading into Ubuntu Oneiric 11.10 with Linux kernel 3.00-12. The problem is with removing the old 64bit kernel 2.6.35-24. The Debian package name is 2.6.35-24. The error I got is following:

[13:41:34] user@machin:[/var/lib/dpkg/info]$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following packages will be REMOVED:
  linux-image-2.6.35-24-generic
0 upgraded, 0 newly installed, 1 to remove and 31 not upgraded.
1 not fully installed or removed.
After this operation, 139 MB disk space will be freed.
Do you want to continue [Y/n]?
(Reading database ... 248250 files and directories currently installed.)
Removing linux-image-2.6.35-24-generic ...
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 2.6.35-24-generic /boot/vmlinuz-2.6.35-24-generic
update-initramfs: Deleting /boot/initrd.img-2.6.35-24-generic
run-parts: executing /etc/kernel/postrm.d/zz-extlinux 2.6.35-24-generic /boot/vmlinuz-2.6.35-24-generic
P: Checking for EXTLINUX directory... found.
P: Writing config for /boot/vmlinuz-3.0.0-12-generic...
E: /usr/share/syslinux/debian/extlinux: No such file or directory
run-parts: /etc/kernel/postrm.d/zz-extlinux exited with return code 1
Failed to process /etc/kernel/postrm.d at /var/lib/dpkg/info/linux-image-2.6.35-24-generic.postrm line 328.
dpkg: error processing linux-image-2.6.35-24-generic (--remove):
 subprocess installed post-removal script returned error exit status 1
Errors were encountered while processing:
 linux-image-2.6.35-24-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)

The highlighted lines told me the error is caused by the postrm script called zz-extlinux located in /etc/kernel/postrm.d/. I don't know how I managed to have extlinux installed on my system. If I am not mistaken booting is still managed by grub-2. So, I decided to remove both extlinux and linux-image-2.6.35-24-generic. But, since my DPKG is already going crazy removing linux-image-2.6.35-24-generic and failing on zz-extlinux, I have to remove the old Linux image first. I quickly patched the zz-extlinux script with an "exit 0" at top followed by an "sudo apt-get -f install". One could also make it non-executable as following as a solution, followe:

sudo chmod -x /etc/kernel/postrm.d/zz-extlinux; sudo apt-get -f install

This solved my problem removing the Linux image. Now, I guess one can also remove extlinux considering Grub-2 is the bootloader.

sudo apt-get remove --purge extlinux

Changing Gnome-Screensaver Background on Lubuntu 11.10 (Oneiric)

I had to find a way on Lubuntu flavoured LXDE to lock/unlock the current running desktop session. The obvious easy way is to use xscreensaver and/or gnome-screensaver and do one of the following:

xscreensaver-command -lock

gnome-screensaver-command --lock

I chose to keep with gnome-screensaver since it is prettier. But immediate annoyance was after locking screen, gnome-screensaver would not retain the same background as current Lubuntu session. After trying so many options (gconf, editing files in /etc), finally I figured - the solution is rather easy.

It appears Lubutu session keeps a separate sets of options from LXDE. When gnome-screensaver is launched, it takes the background option of LXDE (not Lubuntu). To match same background both on LXDE and Lubuntu, which also matches gnome-screensaver background inside Lubuntu session, the steps are below:

1. Set preferred desktop background on running Lubuntu session by right-click > Desktop Preferences > Background.
2. Log-out from Lubuntu session.
3. On the log-in prompt, select LXDE as desktop session to log into.
4. Once inside LXDE, you'll see the desktop background that gnome-screensaver uses as background.
5. From the right-click menu, change the background to match your preference.

That's all !!! Now, you can log in back into Lubuntu and lock screen by initiating gnome-screensaver (I use a Compiz command shortcut with Ctrl+Alt+L which triggers "gnome-screensaver-command --lock") and desktop background will match.