README.md: reformatting, mention distribution packages

* reformat so that it fits into 72 characters per line
* consistently use Gtk+
* reword some parts
* mention how to properly enable it in Debian
* mention packaged version in Debian unstable
* reference screenshots from repository, not external site

README.md

@@ -1,51 +1,89 @@
 #gtk3-nocsd
 
-gtk3-nocsd is a small module used to disable the client side decoration of gtk+ 3.
+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.
+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.
+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.
+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`.
+This is how the gtk3 windows look like before and after using
+`gtk3-nocsd`.
 
-![](http://i.imgur.com/7rMRozy.png)
+![Screenshot of gedit with CSDs still enabled](gedit-with-csd.png)
 
-![](http://i.imgur.com/Ic4pUs9.png)
+![Screenshot of gedit with CSDs disabled by gtk3-nocsd](gedit-without-csd.png)
 
 #How to use:
 
-* Make sure your gtk+ version is either older than 3.16.1 or newer than
-3.17.3.
-* Install necessary packages.  
-On Debian based systems, install `pkg-config`, `libgtk-3-dev`, `libgirepository1.0-dev`.  
-On Rpm based distros, install `pkgconfig`, `gtk3-devel`, `gtk+-devel`, `gobject-introspection-devel`.
+* 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 gtk3 apps(say gedit) using this hack, use the command `./gtk3-nocsd gedit` from the same directory.
-* To have all gtk3 apps(of current user) use this hack, export some environment variables in your `~/.bashrc`.  
+  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>
+        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
 
 * Re-login to make the environment variables take effect.
 
-* Hooray! GTK+ 3 client-side decoration is dead now.
+* Hooray! GTK+ 3 client-side decorations are disabled now.
 
-#How it works:
+#Distribution packages:
 
-I use $LD_PRELOAD to override several gdk and glib/gobject APIs to
-intercept related calls gtk+ 3 uses to setup CSD.
-While gtk+ 3 is trying to initialize CSD, I let it think that there
-is no compositor available, so CSD fail to start.
-Actually, we never disable X compositing, so other parts are not affected.
-This hack to my knowledge is the most specific way to disable CSD
-without obvious side effects.
+gtk3-nocsd is packaged in Debian's unstable distribution, see
+[gtk3-nocsd in Debian's package database](https://packages.debian.org/unstable/gtk3-nocsd).
+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. While Gtk+ 3 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,
+the `gtk_window_set_titlebar` method is re-implemented, as they do not
+allow for the disabling of CSDs via the compositor trick. Since X
+compositing is never really disabled (nor are other parts of Gtk+ 3 led
+to believe so), this does not have adverse consequences. This appears
+to be the simplest way to disable CSDs without obvious side effects.