[gtk+] Add an example for synchronized scrolling

[Matthias Clasen <matthiasc src gnome org>]

commit 9dcb33ad344d00c5548cb2bc1479dcda9e4580aa
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Oct 9 20:17:10 2014 -0400

    Add an example for synchronized scrolling
    
    This example uses GTK_POLICY_EXTERNAL to share a scrollbar among
    multiple scrolled windows.

 tests/Makefile.am  |    1 +
 tests/syncscroll.c |   69 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 0 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 362f89b..78b9b29 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -25,6 +25,7 @@ testsocket_programs = testsocket testsocket_child
 endif
 
 noinst_PROGRAMS =  $(TEST_PROGS)       \
+       syncscroll                      \
        subsurface                      \
        animated-resizing               \
        animated-revealing              \
diff --git a/tests/syncscroll.c b/tests/syncscroll.c
new file mode 100644
index 0000000..881ad64
--- /dev/null
+++ b/tests/syncscroll.c
@@ -0,0 +1,69 @@
+#include <gtk/gtk.h>
+
+static void
+fill_text_view (GtkWidget *tv, const gchar *text)
+{
+  gint i;
+  GString *s;
+
+  s = g_string_new ("");
+  for (i = 0; i < 200; i++)
+    g_string_append_printf (s, "%s %d\n", text, i);
+
+  gtk_text_buffer_set_text (gtk_text_view_get_buffer (GTK_TEXT_VIEW (tv)),
+                            g_string_free (s, FALSE), -1); 
+}
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *win, *box, *tv, *sw, *sb;
+  GtkAdjustment *adj;
+
+  gtk_init (NULL, NULL);
+
+  win = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_default_size (GTK_WINDOW (win), 640, 480);
+
+  box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 5);
+  gtk_container_add (GTK_CONTAINER (win), box);
+
+  sw = gtk_scrolled_window_new (NULL, NULL);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                  GTK_POLICY_NEVER,
+                                  GTK_POLICY_EXTERNAL);
+  gtk_box_pack_start (GTK_BOX (box), sw, TRUE, TRUE, 0);
+  tv = gtk_text_view_new ();
+  fill_text_view (tv, "Left");
+  gtk_container_add (GTK_CONTAINER (sw), tv);
+
+  adj = gtk_scrolled_window_get_vadjustment (GTK_SCROLLED_WINDOW (sw));
+
+  sw = gtk_scrolled_window_new (NULL, adj);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                  GTK_POLICY_NEVER,
+                                  GTK_POLICY_EXTERNAL);
+  gtk_box_pack_start (GTK_BOX (box), sw, TRUE, TRUE, 0);
+  tv = gtk_text_view_new ();
+  fill_text_view (tv, "Middle");
+  gtk_container_add (GTK_CONTAINER (sw), tv);
+
+  sw = gtk_scrolled_window_new (NULL, adj);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                  GTK_POLICY_NEVER,
+                                  GTK_POLICY_EXTERNAL);
+  gtk_box_pack_start (GTK_BOX (box), sw, TRUE, TRUE, 0);
+  tv = gtk_text_view_new ();
+  fill_text_view (tv, "Right");
+  gtk_container_add (GTK_CONTAINER (sw), tv);
+
+  sb = gtk_scrollbar_new (GTK_ORIENTATION_VERTICAL, adj);
+
+  gtk_container_add (GTK_CONTAINER (box), sb);
+
+  gtk_widget_show_all (win);
+
+  gtk_main ();
+
+  return 0;
+}