tests/examples: add a demo for the interpolation control source modes

This is in preparation for new modes to be added. In particullar it demonstrates
how the cubic splines overshoot the range.

configure.ac

@@ -775,6 +775,16 @@ dnl Check for documentation xrefs
 GLIB_PREFIX="`$PKG_CONFIG --variable=prefix glib-2.0`"
 AC_SUBST(GLIB_PREFIX)
 
+dnl GTK is optional and only used in examples
+HAVE_GTK=no
+GTK_REQ=3.10
+if test "x$BUILD_EXAMPLES" = "xyes"; then
+  PKG_CHECK_MODULES(GTK, gtk+-3.0 >= $GTK_REQ, HAVE_GTK=yes, HAVE_GTK=no)
+  AC_SUBST(GTK_LIBS)
+  AC_SUBST(GTK_CFLAGS)
+fi
+AM_CONDITIONAL(HAVE_GTK, test "x$HAVE_GTK" = "xyes")
+
 dnl building of unit test libraries
 AC_ARG_ENABLE(check,
   AS_HELP_STRING([--disable-check],[disable building unit test libraries]),

tests/examples/controller/.gitignore

@@ -1,5 +1,6 @@
 audio-example
 control-sources
+controller-graph
 text-color-example
 absolute-example
 *.bb

tests/examples/controller/Makefile.am

@@ -5,3 +5,13 @@ AM_CFLAGS  = $(GST_OBJ_CFLAGS) -I$(top_builddir)/libs
 LDADD = \
 	$(top_builddir)/libs/gst/controller/libgstcontroller-@GST_API_VERSION@.la \
 	$(GST_OBJ_LIBS)
+
+if HAVE_GTK
+noinst_PROGRAMS += controller-graph
+
+controller_graph_CFLAGS = $(GST_OBJ_CFLAGS) $(GTK_CFLAGS)
+controller_graph_LDADD = \
+	$(top_builddir)/libs/gst/controller/libgstcontroller-@GST_API_VERSION@.la \
+	$(GST_OBJ_LIBS) $(GTK_LIBS)
+
+endif

tests/examples/controller/controller-graph.c

@@ -0,0 +1,185 @@
+/* GStreamer
+ * Copyright (C) <2015> Stefan Sauer <ensonic@users.sf.net>
+ *
+ * controller-graph: explore interpolation types
+ *
+ * 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., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <math.h>
+
+#include <glib.h>
+#include <gtk/gtk.h>
+
+#include <gst/gst.h>
+#include <gst/controller/gstinterpolationcontrolsource.h>
+
+GtkWidget *graph;
+GstControlSource *cs = NULL;
+gdouble yval[] = { 0.0, 0.2, 0.8, 0.1, 0.1, 1.0 };
+
+static gboolean
+on_graph_draw (GtkWidget * widget, cairo_t * cr, gpointer user_data)
+{
+  GtkStyleContext *style = gtk_widget_get_style_context (widget);
+  GtkAllocation alloc;
+  gint x, y, w, h;
+  gdouble *data;
+  guint64 ts, ts_step;
+  gint i;
+  GstTimedValueControlSource *tvcs = (GstTimedValueControlSource *) cs;
+
+  gtk_widget_get_allocation (widget, &alloc);
+  w = alloc.width;
+  h = alloc.height;
+  gtk_render_background (style, cr, 0, 0, w, h);
+  // add some border:
+  x = 5;
+  y = 5;
+  w -= (x + x);
+  h -= (y + y);
+
+  // build graph
+  ts = G_GUINT64_CONSTANT (0);
+  ts_step = w / (G_N_ELEMENTS (yval) - 1);
+  gst_timed_value_control_source_unset_all (tvcs);
+  for (i = 0; i < G_N_ELEMENTS (yval); i++) {
+    gst_timed_value_control_source_set (tvcs, ts, yval[i]);
+    ts += ts_step;
+  }
+  data = g_new (gdouble, w);
+  gst_control_source_get_value_array (cs, 0, 1, w, data);
+
+  // draw background
+  cairo_set_source_rgb (cr, 0.5, 0.5, 0.5);
+  cairo_rectangle (cr, x, y, w, h);
+  cairo_stroke_preserve (cr);
+  cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+  cairo_fill (cr);
+
+
+  // plot graph
+  cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+  cairo_set_line_width (cr, 1.0);
+  cairo_move_to (cr, x, y + data[0] * h);
+  for (i = 1; i < w; i++) {
+    cairo_line_to (cr, x + i, y + CLAMP (data[i], 0.0, 1.0) * h);
+  }
+  cairo_stroke (cr);
+
+  // plot control points
+  ts = G_GUINT64_CONSTANT (0);
+  for (i = 0; i < G_N_ELEMENTS (yval); i++) {
+    cairo_set_source_rgb (cr, 0.0, 0.0, 0.0);
+    cairo_arc (cr, x + ts, y + yval[i] * h, 3.0, 0.0, 2 * M_PI);
+    cairo_stroke_preserve (cr);
+    cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
+    cairo_fill (cr);
+    ts += ts_step;
+  }
+
+  g_free (data);
+
+  return TRUE;
+}
+
+static void
+on_mode_changed (GtkComboBox * combo, gpointer user_data)
+{
+  g_object_set (cs, "mode", gtk_combo_box_get_active (combo), NULL);
+  gtk_widget_queue_draw (graph);
+}
+
+static void
+on_yval_changed (GtkSpinButton * spin, gpointer user_data)
+{
+  guint ix = GPOINTER_TO_UINT (user_data);
+  yval[ix] = gtk_spin_button_get_value (spin);
+  gtk_widget_queue_draw (graph);
+}
+
+int
+main (int argc, char **argv)
+{
+  GtkWidget *window;
+  GtkWidget *layout, *label, *combo, *box, *spin;
+  GEnumClass *enum_class;
+  GEnumValue *enum_value;
+  gint i;
+
+  gst_init (&argc, &argv);
+  gtk_init (&argc, &argv);
+
+  cs = gst_interpolation_control_source_new ();
+  g_object_set (cs, "mode", GST_INTERPOLATION_MODE_LINEAR, NULL);
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  g_signal_connect (G_OBJECT (window), "delete-event", gtk_main_quit, NULL);
+  gtk_window_set_default_size (GTK_WINDOW (window), 320, 240);
+  gtk_window_set_title (GTK_WINDOW (window),
+      "GstInterpolationControlSource demo");
+
+  layout = gtk_grid_new ();
+
+  graph = gtk_drawing_area_new ();
+  gtk_widget_add_events (graph, GDK_POINTER_MOTION_MASK);
+  g_signal_connect (graph, "draw", G_CALLBACK (on_graph_draw), NULL);
+  g_object_set (graph, "hexpand", TRUE, "vexpand", TRUE, "margin-bottom", 3,
+      NULL);
+  gtk_grid_attach (GTK_GRID (layout), graph, 0, 0, 2, 1);
+
+  // add controls to move the yvals
+  box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 3);
+  g_object_set (box, "homogeneous", TRUE, "margin-bottom", 3, NULL);
+  for (i = 0; i < G_N_ELEMENTS (yval); i++) {
+    spin = gtk_spin_button_new_with_range (0.0, 1.0, 0.05);
+    gtk_spin_button_set_value (GTK_SPIN_BUTTON (spin), yval[i]);
+    g_signal_connect (spin, "changed", G_CALLBACK (on_yval_changed),
+        GUINT_TO_POINTER (i));
+    gtk_container_add (GTK_CONTAINER (box), spin);
+  }
+  gtk_grid_attach (GTK_GRID (layout), box, 0, 1, 2, 1);
+
+  // combo for interpolation modes
+  label = gtk_label_new ("interpolation mode");
+  gtk_grid_attach (GTK_GRID (layout), label, 0, 2, 1, 1);
+
+  combo = gtk_combo_box_text_new ();
+  enum_class = g_type_class_ref (GST_TYPE_INTERPOLATION_MODE);
+  for (i = enum_class->minimum; i <= enum_class->maximum; i++) {
+    if ((enum_value = g_enum_get_value (enum_class, i))) {
+      gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo),
+          enum_value->value_nick);
+    }
+  }
+  gtk_combo_box_set_active (GTK_COMBO_BOX (combo),
+      GST_INTERPOLATION_MODE_LINEAR);
+  g_signal_connect (combo, "changed", G_CALLBACK (on_mode_changed), NULL);
+  g_object_set (combo, "hexpand", TRUE, "margin-left", 3, NULL);
+  gtk_grid_attach (GTK_GRID (layout), combo, 1, 2, 1, 1);
+
+  gtk_container_set_border_width (GTK_CONTAINER (window), 6);
+  gtk_container_add (GTK_CONTAINER (window), layout);
+  gtk_widget_show_all (window);
+
+  gtk_main ();
+
+  return 0;
+}