added volume demo app

Original commit message from CVS:
added volume demo app

ChangeLog

@@ -1,3 +1,11 @@
+2004-06-14  Thomas Vander Stichele  <thomas at apestaart dot org>
+
+	* gst/volume/.cvsignore:
+	* gst/volume/Makefile.am:
+	* gst/volume/demo.c: (value_changed_callback), (idler),
+	(setup_gui), (main):
+	  added small demo app
+
 2004-06-13  Jan Schmidt  <thaytan@mad.scientist.com>
 	* ext/esd/esdsink.c: (gst_esdsink_change_state):
 	* ext/esd/esdsink.h:

gst/volume/.gitignore

@@ -0,0 +1 @@
+demo

gst/volume/Makefile.am

@@ -8,3 +8,10 @@ libgstvolume_la_LIBADD = $(GST_LIBS) $(GST_CONTROL_LIBS) \
 libgstvolume_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
 
 noinst_HEADERS = gstvolume.h filter.func
+
+if HAVE_GTK
+noinst_PROGRAMS = demo
+demo_SOURCES = demo.c
+demo_CFLAGS = $(GTK_CFLAGS) $(GST_CFLAGS) -D_GNU_SOURCE
+demo_LDFLAGS = $(GTK_LIBS) $(GST_LIBS) -lm
+endif

gst/volume/demo.c

@@ -0,0 +1,132 @@
+/* GStreamer
+ *
+ * demo.c: sample application to change the volume of a pipeline
+ *
+ * Copyright (C) <2004> Thomas Vander Stichele <thomas at apestaart dot org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <math.h>
+
+#include <gst/gst.h>
+#include <gtk/gtk.h>
+
+/* global pointer for the scale widget */
+GtkWidget *elapsed;
+GtkWidget *scale;
+
+static void
+value_changed_callback (GtkWidget * widget, GstElement * volume)
+{
+  gdouble value;
+  gdouble level;
+
+  value = gtk_range_get_value (GTK_RANGE (widget));
+  level = exp10 (value / 20.0);
+  g_print ("Value: %f dB, level: %f\n", value, level);
+  g_object_set (volume, "volume", level, NULL);
+}
+
+static gboolean
+idler (gpointer data)
+{
+  GstElement *pipeline = GST_ELEMENT (data);
+
+  g_print ("+");
+  if (gst_bin_iterate (GST_BIN (pipeline)))
+    return TRUE;
+  gtk_main_quit ();
+  return FALSE;
+}
+
+static void
+setup_gui (GstElement * volume)
+{
+  GtkWidget *window;
+  GtkWidget *vbox;
+  GtkWidget *label, *hbox;
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  g_signal_connect (window, "destroy", gtk_main_quit, NULL);
+
+  vbox = gtk_vbox_new (TRUE, 0);
+  gtk_container_add (GTK_CONTAINER (window), vbox);
+
+  /* elapsed widget */
+  hbox = gtk_hbox_new (TRUE, 0);
+  label = gtk_label_new ("Elapsed");
+  elapsed = gtk_label_new ("0.000");
+  gtk_container_add (GTK_CONTAINER (hbox), label);
+  gtk_container_add (GTK_CONTAINER (hbox), elapsed);
+  gtk_container_add (GTK_CONTAINER (vbox), hbox);
+
+  /* volume */
+  hbox = gtk_hbox_new (TRUE, 0);
+  label = gtk_label_new ("volume");
+  gtk_container_add (GTK_CONTAINER (hbox), label);
+  scale = gtk_hscale_new_with_range (-90.0, 10.0, 0.2);
+  gtk_range_set_value (GTK_RANGE (scale), 0.0);
+  gtk_widget_set_size_request (scale, 100, -1);
+  gtk_container_add (GTK_CONTAINER (hbox), scale);
+  gtk_container_add (GTK_CONTAINER (vbox), hbox);
+  g_signal_connect (scale, "value-changed",
+      G_CALLBACK (value_changed_callback), volume);
+
+  gtk_widget_show_all (GTK_WIDGET (window));
+}
+
+int
+main (int argc, char *argv[])
+{
+
+  GstElement *pipeline = NULL;
+  GError *error = NULL;
+  GstElement *volume;
+
+  gst_init (&argc, &argv);
+  gtk_init (&argc, &argv);
+
+  pipeline = gst_parse_launchv ((const gchar **) &argv[1], &error);
+  if (error) {
+    g_print ("pipeline could not be constructed: %s\n", error->message);
+    g_print ("Please give a complete pipeline  with a 'volume' element.\n");
+    g_print ("Example: sinesrc ! volume ! osssink\n");
+    g_error_free (error);
+    return 1;
+  }
+
+  volume = gst_bin_get_by_name (GST_BIN (pipeline), "volume0");
+  if (volume == NULL) {
+    g_print ("Please give a pipeline with a 'volume' element in it\n");
+    return 1;
+  }
+
+  /* setup GUI */
+  setup_gui (volume);
+
+  /* go to main loop */
+  gst_element_set_state (pipeline, GST_STATE_PLAYING);
+  g_idle_add (idler, pipeline);
+
+  gtk_main ();
+
+  return 0;
+}