use the enum module to represent states

[~helmut/onoff.git] / README.md

diff --git a/README.md b/README.md
index d0488f3..cd41bc6 100644 (file)
--- a/README.md
+++ b/README.md
@@ -30,6 +30,15 @@ Use cases
    services. This is another inhibiting strategy. It is already being solved by
    [systemd-inhibit][] though.
 
+Dependencies
+============
+
+ * At least Python version 3.5 (e.g. Debian stretch).
+ * python3-dbus
+ * python3-gi
+ * python3-mpd if you intend to use `mpd_watcher.py`
+ * sispmctl if you intend to control a power socket with this tool
+
 API
 ===
 
@@ -39,28 +48,34 @@ also must provide a `state` attribute to query the current device state. When
 the devices changes its state, it must invoke the `changestate` method to
 signal interested parties.
 
-There currently are four implementations. An `OnoffCommand` can be used if the
-state of a device can be changed by invoking a command for either direction.
-The transition is considered complete when the respective command terminates.
-This device is used to implement a power socket with [sispmctl][] in
-`onoff.tools.sispmctl_device`.
+There currently are four implementations.
+
+ *  An `OnoffCommand` can be used if the state of a device can be changed by
+    invoking a command for either direction.  The transition is considered
+    complete when the respective command terminates.  This device is used to
+    implement a power socket with [sispmctl][] in
+    `onoff.tools.sispmctl_device`.
+
+ *  An `OnoffProcess` can be used if the device is considered active as long as
+    the process runs. Deactivation is achieved by killing the process. For
+    example [redshift][] can be started in this way.
 
-An `OnoffProcess` can be used if the device is considered active as long as the
-process runs. Deactivation is achieved by killing the process. For example the
-[redshift][] can be started in this way.
+        dev = onoff.processs.OnoffProcess(["redshift"])
 
-    dev = onoff.processs.OnoffProcess(["redshift"], 3)
+    To account for the time it takes the process to start up, it can be wrapped
+    in a `ThrottledDevice` (see below).
 
-An `InvertedDevice` can be used to swap the activation states. It can be used
-to activate a device all the time and inhibit activation whenever the inverted
-device is activated. So an `InvertedDevice` wraps an existing `OnoffDevice`.
+ *  An `InvertedDevice` can be used to swap the activation states. It can be
+    used to activate a device all the time and inhibit activation whenever the
+    inverted device is activated. So an `InvertedDevice` wraps an existing
+    `OnoffDevice`.
 
-A `ThrottledDevice` can be used to add artificial delays to the transition
-periods of the activation and deactivation. If a device takes noticeable time
-to settle even after it has been signaled as active, the activation signal can
-be delayed. Similarly if a device should not be switched too often,
-deactivation can be delayed. If the device is reactivated shortly after it has
-been released, it simply keeps being active.
+ *  A `ThrottledDevice` can be used to add artificial delays to the transition
+    periods of the activation and deactivation. If a device takes noticeable
+    time to settle even after it has been signaled as active, the activation
+    signal can be delayed. Similarly if a device should not be switched too
+    often, deactivation can be delayed. If the device is reactivated shortly
+    after it has been released, it simply keeps being active.
 
 Once you have an `OnoffDevice` you can pass a dbus bus connection, a name and
 the device to the `OnoffControl` constructor. The created object exports the