# gtk3-nocsd

gtk3-nocsd is a small module used to disable the client side decoration of Gtk+ 3.

## Introduction:

Since Gtk+ 3.10, its developers added a so-called header bar or custom title bar. With this and the client-side decoration, the original title bar and window border provided by the window manager are disabled by Gtk+. This makes all Gtk+ 3 programs look alike. Even worse, this may break some window manager or compositors.

Unfortunately, the Gtk+ developers decided to be against the existing standards and provide "no option" to turn it off.

Luckily, with gtk3-nocsd, we still have a way to (partially) turn it off. Window manager (title bar and window border) can be re-enabled.

## Preview:

This is how the gtk3 windows look like before and after using `gtk3-nocsd`.

# How to use:

- gtk3-nocsd should work with all Gtk+ 3 versions.

- Install necessary packages:

  - On Debian-based systems (including Ubuntu and Mint), install `pkg-config`, `libgtk-3-dev`, `libgirepository1.0-dev`.

  - On Fedora-based distros (including RHEL, CentOS), install `pkgconfig`, `gtk3-devel`, `gtk+-devel`, `gobject-introspection-devel`.

- Build the code. Run `make` from command line. After this you'll have the files `gtk3-nocsd`and `libgtk3-nocsd.so.0` in the same directory.

- Now to run individual Gtk+ 3 apps (say gedit) using this hack, use the command `./gtk3-nocsd gedit` from the same directory.

- To have all Gtk+ 3 apps (of current user) use this hack, export some environment variables in your `~/.bashrc`:

      export GTK_CSD=0
      export LD_PRELOAD=<"full path" of your libgtk3-nocsd.so.0 file>

- On Debian-based systems with graphical login, instead modify (or create) `~/.xsessionrc` and add the following code:

      if [ -n "$STARTUP" ]; then
        BASESTARTUP=${STARTUP%% *}
        BASESTARTUP=${BASESTARTUP##*/}
        if [ "$BASESTARTUP" = x-session-manager ]; then
          BASESTARTUP=$(basename $(readlink /etc/alternatives/x-session-manager))
        fi
        if [ x"$BASESTARTUP" = x"${BASESTARTUP#gnome-session}" ] ; then
          export GTK_CSD=0
          STARTUP="env LD_PRELOAD=/path/to/libgtk3-nocsd.so.0 $STARTUP"
        fi
      fi

  gtk3-nocsd is now packaged for Debian though (see below), so manual installation may not be necessary.

- Re-login to make the environment variables take effect.

- Hooray! GTK+ 3 client-side decorations are disabled now.

# Distribution packages:

gtk3-nocsd is packaged in Debian's unstable and testing distributions, see gtk3-nocsd in Debian's package database. The Debian package already comes with integration code to automatically disable CSDs when installed, so after package installation only a re-login is required to have CSDs disabled on non-GNOME desktops.

# How it works:

`$LD_PRELOAD` is used to override several Gdk and glib/gobject APIs to intercept related calls Gtk+ 3 uses to setup CSDs. For older versions of Gtk+ 3, while it is trying to initialize CSDs, it is led to believe that there is no compositor available, so CSDs are not added. For later Gtk+ 3 versions (3.16.1+), the `gtk_window_set_titlebar` method is reimplemented, as tricking Gtk+ 3 into thinking the compositor is disabled has side effects and is not sufficent anymore.

Additionally, as gtkwindowsettitlebar is also called from Gtk+ internally (and LDPRELOAD cannot override function calls within a library), several other places in Gtk+3 (e.g. buildable interfaces for GtkWindow and GtkDialog) are also overridden to ensure that CSDs are disabled.