[gnome-devel-docs] add the webcam demo written in vala

[Daniel G. Siegel <dgsiegel src gnome org>]

commit 57e16b2d0282e91de3f49db4f63709c8e06bd44f
Author: daniel g. siegel <dgsiegel gnome org>
Date:   Thu Dec 2 23:37:57 2010 +0100

    add the webcam demo written in vala

 demos/webcam/webcam.vala |   70 ++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 70 insertions(+), 0 deletions(-)
---
diff --git a/demos/webcam/webcam.vala b/demos/webcam/webcam.vala
new file mode 100644
index 0000000..d4ce63d
--- /dev/null
+++ b/demos/webcam/webcam.vala
@@ -0,0 +1,70 @@
+/*
+ * Compile using:
+ * valac --pkg gtk+-2.0 --pkg gdk-x11-2.0 --pkg gstreamer-0.10 --pkg gstreamer-interfaces-0.10 webcam.vala
+ *
+ */
+using Gtk;
+using Gst;
+
+public class Webcam : Window
+{
+  private DrawingArea drawing_area;
+  private Element camerabin;
+  private int counter = 1;
+
+  public Webcam ()
+  {
+    var vbox = new VBox (false, 0);
+    this.drawing_area = new DrawingArea ();
+    this.drawing_area.set_size_request (640, 480);
+    vbox.pack_start (this.drawing_area, true, true, 0);
+
+    var photo_button = new Button.with_label ("Take a picture");
+    photo_button.clicked.connect (on_take_picture);
+
+    var button_box = new HButtonBox ();
+    button_box.add (photo_button);
+    vbox.pack_start (button_box, false, true, 0);
+
+    this.add (vbox);
+
+    this.camerabin = Gst.ElementFactory.make ("camerabin", "camera");
+    var bus = this.camerabin.get_bus ();
+    bus.set_sync_handler (on_bus_callback);
+
+    this.camerabin.set_state (State.PLAYING);
+  }
+
+  private BusSyncReply on_bus_callback (Gst.Bus bus, Gst.Message message)
+  {
+
+    if (message.get_structure () != null && message.get_structure().has_name("prepare-xwindow-id")) {
+      var xoverlay = message.src as XOverlay;
+      xoverlay.set_xwindow_id (Gdk.x11_drawable_get_xid (this.drawing_area.window));
+      return BusSyncReply.DROP;
+    }
+
+    return BusSyncReply.PASS;
+  }
+
+  private void on_take_picture ()
+  {
+    var filename = "photo" + "%d".printf (this.counter) + ".jpg";
+    this.counter++;
+    this.camerabin.set ("filename", filename);
+    Signal.emit_by_name (this.camerabin, "capture-start");
+  }
+
+  public static int main (string[] args)
+  {
+    Gst.init (ref args);
+    Gtk.init (ref args);
+
+    var webcam = new Webcam ();
+    webcam.show_all ();
+
+    Gtk.main ();
+
+    return 0;
+  }
+}