Feature chjj#80: D-Bus support

- Add D-Bus support. Currently 7 methods are available: "reset" (same as
  SIGUSR1), "list_win" (list the windows compton manages), "win_get"
  (get a property of the window), "win_set" (set a property of the
  window), "find_win" (find window based on client window / focus),
  "opts_get" (get the value of a compton option), and "opts_set" (set
  the value of a compton option), together with 4 signals: "win_added",
  "win_destroyed", "win_mapped", "win_unmapped".

- D-Bus support depends on libdbus.

- As there are many items and my time is tight, no much tests are done.
  Bugs to be expected.

- Create a new header file `common.h` that contains shared content.

- Fix some bugs in timeout handling.

- Update file headers in all source files.

- Re-enable --unredir-if-possible on multi-screen set-ups, as the user
  could turn if off manually anyway.

- Check if the window is mapped in `repair_win()`.

- Add ps->track_atom_lst and its handlers, to prepare for the new
  condition format.

- Known issue 1: "win_get", "win_set", "opts_get", "opts_set" support a
  very limited number of targets only. New ones will be added gradually.

- Known issue 2: Accidental drop of D-Bus connection is not handled.

- Known issue 3: Introspection does not reveal all available methods,
  because some methods have unpredictable prototypes. Still hesitating
  about what to do...

- Known issue 4: Error handling is not finished yet. Compton does not
  always reply with the correct error message (but it does print out the
  correct error message, usually).

Makefile

@@ -11,6 +11,8 @@ PACKAGES = x11 xcomposite xfixes xdamage xrender xext xrandr
 LIBS = -lm -lrt
 INCS =
 
+OBJS = compton.o
+
 # === Configuration flags ===
 CFG =
 
@@ -46,10 +48,11 @@ ifeq "$(NO_VSYNC_OPENGL)" ""
 endif
 
 # ==== D-Bus ====
-# ifeq "$(NO_DBUS)" ""
-#   CFG += -DCONFIG_DBUS
-#   PACKAGES += dbus-1
-# endif
+ifeq "$(NO_DBUS)" ""
+  CFG += -DCONFIG_DBUS
+  PACKAGES += dbus-1
+  OBJS += dbus.o
+endif
 
 # === Version string ===
 COMPTON_VERSION ?= git-$(shell git describe --always --dirty)-$(shell git log -1 --date=short --pretty=format:%cd)
@@ -63,14 +66,13 @@ LIBS += $(shell pkg-config --libs $(PACKAGES))
 INCS += $(shell pkg-config --cflags $(PACKAGES))
 
 CFLAGS += -Wall -std=c99
-OBJS = compton.o
 MANPAGES = man/compton.1 man/compton-trans.1
 MANPAGES_HTML = $(addsuffix .html,$(MANPAGES))
 
 # === Recipes ===
 .DEFAULT_GOAL := compton
 
-%.o: src/%.c src/%.h
+%.o: src/%.c src/%.h src/common.h
 	$(CC) $(CFLAGS) $(INCS) -c src/$*.c
 
 compton: $(OBJS)

README.md

@@ -11,17 +11,18 @@ partially doing this out of a desire to learn Xlib.
 
 ## Changes from xcompmgr:
 
-* __inactive window transparency__ (specified with `-i`)
+* __inactive window transparency / dimming__
 * __titlebar/frame transparency__ (specified with `-e`)
 * menu transparency (thanks to Dana)
 * shadows are now enabled for argb windows, e.g. terminals with transparency
 * removed serverside shadows (and simple compositing) to clean the code,
   the only option that remains is clientside shadows
-* configuration files (specified with `--config`)
-* colored shadows (with `--shadow-[red/green/blue] value`)
+* configuration files (see the man page for more details)
+* colored shadows (`--shadow-[red/green/blue]`)
 * a new fade system
-* vsync (still under development)
-* several more options
+* VSync support (not always working)
+* Blur of background of transparent windows, window color inversion (bad in performance)
+* Some more options...
 
 ## Fixes from the original xcompmgr:
 
@@ -51,10 +52,11 @@ __R__ for runtime
 * xproto / x11proto (B)
 * bash (R)
 * xprop,xwininfo / x11-utils (R)
-* libpcre (B,R) (Will probably be made optional soon)
-* libconfig (B,R) (Will probably be made optional soon)
-* libdrm (B) (Will probably be made optional soon)
-* libGL (B,R) (Will probably be made optional soon)
+* libpcre (B,R) (Can be disabled with `NO_REGEX_PCRE` at compile time)
+* libconfig (B,R) (Can be disabled with `NO_LIBCONFIG` at compile time)
+* libdrm (B) (Can be disabled with `NO_VSYNC_DRM` at compile time)
+* libGL (B,R) (Can be disabled with `NO_VSYNC_OPENGL` at compile time)
+* libdbus (B,R) (Can be disabled with `NO_DBUS` at compile time)
 * asciidoc (B)
 
 ### How to build
@@ -64,7 +66,7 @@ To build, make sure you have the dependencies above:
 ``` bash
 # Make the main program
 $ make
-# Make the newer man pages
+# Make the man pages
 $ make docs
 # Install
 $ make install

dbus-examples/cdbus-driver.sh

@@ -0,0 +1,45 @@
+#!/bin/sh
+
+# === Get connection parameters ===
+
+dpy=$(echo -n "$DISPLAY" | tr -c '[:alnum:]' _)
+
+if [ -z "$dpy" ]; then
+  echo "Cannot find display."
+  exit 1
+fi
+
+service="com.github.chjj.compton.${dpy}"
+interface='com.github.chjj.compton'
+object='/com/github/chjj/compton'
+type_win='uint32'
+type_enum='uint16'
+
+# === DBus methods ===
+
+# List all window ID compton manages (except destroyed ones)
+dbus-send --print-reply --dest="$service" "$object" "${interface}.list_win"
+
+# Get window ID of currently focused window
+focused=$(dbus-send --print-reply --dest="$service" "$object" "${interface}.find_win" string:focused | sed -n 's/^[[:space:]]*'${type_win}'\s*\([[:digit:]]*\).*/\1/p')
+
+if [ -n "$focused" ]; then
+  # Get invert_color_force property of the window
+  dbus-send --print-reply --dest="$service" "$object" "${interface}.win_get" "${type_win}:${focused}" string:invert_color_force
+
+  # Set the window to have inverted color
+  dbus-send --print-reply --dest="$service" "$object" "${interface}.win_set" "${type_win}:${focused}" string:invert_color_force "${type_enum}:1"
+else
+  echo "Cannot find focused window."
+fi
+
+# Set the clear_shadow setting to true
+dbus-send --print-reply --dest="$service" "$object" "${interface}.opts_set" string:clear_shadow boolean:true
+
+# Get the clear_shadow setting
+dbus-send --print-reply --dest="$service" "$object" "${interface}.opts_get" string:clear_shadow
+
+# Reset compton
+sleep 3
+dbus-send --print-reply --dest="$service" "$object" "${interface}.reset"
+