[gtk+] Add an experiment for overlay scrollbars

[Matthias Clasen <matthiasc src gnome org>]

commit 05ab0f222701d71fc3a96a724d5d9ad34c7c7efe
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Oct 4 23:37:11 2014 -0400

    Add an experiment for overlay scrollbars
    
    This is just meant as a prototype for how we can show a
    scroll position indicator for touch. This uses GTK_POLICY_EXTERNAL
    to hide the scrolled windows scrollbar while still allowing
    scrolling.

 tests/Makefile.am     |    1 +
 tests/overlayscroll.c |  376 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 377 insertions(+), 0 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 779a611..b8355cf 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -26,6 +26,7 @@ testsocket_programs = testsocket testsocket_child
 endif
 
 noinst_PROGRAMS =  $(TEST_PROGS)       \
+       overlayscroll                   \
        syncscroll                      \
        subsurface                      \
        animated-resizing               \
diff --git a/tests/overlayscroll.c b/tests/overlayscroll.c
new file mode 100644
index 0000000..478c229
--- /dev/null
+++ b/tests/overlayscroll.c
@@ -0,0 +1,376 @@
+/* simple.c
+ * Copyright (C) 1997  Red Hat, Inc
+ * Author: Elliot Lee
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <gtk/gtk.h>
+#include <string.h>
+
+typedef struct {
+  GtkWidget *sw;
+  GtkWidget *rv;
+  gint64 last_scroll_time;
+  gboolean over;
+  gboolean dragging;
+  gboolean autodetect;
+  gboolean touch_mode;
+} IndicatorData;
+
+IndicatorData *
+get_indicator_data (GtkWidget *sb)
+{
+  IndicatorData *data;
+
+  data = (IndicatorData *) g_object_get_data (G_OBJECT (sb), "indicator-data");
+
+  if (!data)
+    {
+      data = g_new0 (IndicatorData, 1);
+      g_object_set_data_full (G_OBJECT (sb), "indicator-data", data, g_free);
+    }
+
+  return data;
+}
+
+static gboolean
+conceil_scrollbar (gpointer data)
+{
+  GtkWidget *sb = data;
+  IndicatorData *id = get_indicator_data (sb);
+
+  if (g_get_monotonic_time () - id->last_scroll_time >= 1000000 &&
+      id->touch_mode &&
+      !id->over &&
+      !id->dragging)
+    {
+      if (gtk_revealer_get_reveal_child (GTK_REVEALER (id->rv)))
+        gtk_revealer_set_reveal_child (GTK_REVEALER (id->rv), FALSE);
+    }
+
+  return G_SOURCE_CONTINUE;
+}
+
+static void
+value_changed (GtkAdjustment *adj, GtkWidget *sb)
+{
+  IndicatorData *id = get_indicator_data (sb);
+
+  if (id->touch_mode &&
+      !gtk_revealer_get_reveal_child (GTK_REVEALER (id->rv)))
+    gtk_revealer_set_reveal_child (GTK_REVEALER (id->rv), TRUE);
+
+  id->last_scroll_time = g_get_monotonic_time ();  
+}
+
+static gboolean
+enter_notify (GtkWidget *sb, GdkEventCrossing *event)
+{
+  GtkStyleContext *context = gtk_widget_get_style_context (sb);
+  IndicatorData *id = get_indicator_data (sb);
+
+  gtk_style_context_add_class (context, "locked");
+  gtk_widget_queue_resize (sb);
+  id->over = TRUE;
+
+  return G_SOURCE_CONTINUE;
+}
+
+static gboolean
+leave_notify (GtkWidget *sb, GdkEventCrossing *event)
+{
+  GtkStyleContext *context = gtk_widget_get_style_context (sb);
+  IndicatorData *id = get_indicator_data (sb);
+
+  gtk_style_context_remove_class (context, "locked");
+  gtk_widget_queue_resize (sb);
+  id->over = FALSE;
+
+  return G_SOURCE_CONTINUE;
+}
+
+static void
+style_changed (GtkStyleContext *context, GtkWidget *sb)
+{
+  IndicatorData *id = get_indicator_data (sb);
+
+  if (gtk_style_context_has_class (context, "dragging"))
+    id->dragging = TRUE;
+  else
+    id->dragging = FALSE;
+}
+
+static const gchar *
+input_source (GdkInputSource source)
+{
+  switch (source)
+    {
+    case GDK_SOURCE_MOUSE: return "mouse";
+    case GDK_SOURCE_PEN: return "pen";
+    case GDK_SOURCE_ERASER: return "eraser";
+    case GDK_SOURCE_CURSOR: return "cursor";
+    case GDK_SOURCE_KEYBOARD: return "keyboard";
+    case GDK_SOURCE_TOUCHSCREEN: return "touchscreen";
+    case GDK_SOURCE_TOUCHPAD: return "touchpad";
+    default: return "unknown";
+    }
+}
+
+static void
+list_devices (GdkDeviceManager *dm)
+{
+  GList *devices, *l;
+  GList *slaves, *s;
+  GdkDevice *device;
+
+  devices = gdk_device_manager_list_devices (dm, GDK_DEVICE_TYPE_MASTER);
+  for (l = devices; l; l = l->next)
+    {
+      device = l->data;
+      g_print ("%s%s\n",
+               gdk_device_get_name (device),
+               gdk_device_get_has_cursor (device) ? ", has cursor" : "");
+      slaves = gdk_device_list_slave_devices (device);
+      for (s = slaves; s; s = s->next)
+        {
+          device = s->data;
+          g_print ("  ↳ %s, %s\n",
+                   gdk_device_get_name (device),
+                   input_source (gdk_device_get_source (device)));
+        }
+      g_list_free (slaves);
+    }
+  g_list_free (devices);
+}
+
+static gboolean
+has_mouse (GdkDeviceManager *dm)
+{
+  GdkDevice *cp;
+  GList *slaves, *s;
+  GdkDevice *device;
+  gboolean found;
+
+  found = FALSE;
+
+  cp = gdk_device_manager_get_client_pointer (dm);
+  slaves = gdk_device_list_slave_devices (cp);
+  for (s = slaves; s; s = s->next)
+    {
+      device = s->data;
+
+      if (gdk_device_get_source (device) != GDK_SOURCE_MOUSE)
+        continue;
+
+      if (strstr (gdk_device_get_name (device), "XTEST"))
+        continue;
+
+      if (strstr (gdk_device_get_name (device), "TrackPoint"))
+        continue;
+
+      if (g_object_get_data (G_OBJECT (device), "removed"))
+        continue;
+
+      found = TRUE;
+      break;
+    }
+  g_list_free (slaves);
+
+  return found;
+}
+
+static void
+update_touch_mode (IndicatorData *id, gboolean touch_mode)
+{
+  id->touch_mode = touch_mode;
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (id->sw),
+                                  GTK_POLICY_NEVER,
+                                  id->touch_mode ? GTK_POLICY_EXTERNAL : GTK_POLICY_AUTOMATIC);
+
+  g_print ("touch mode now %s\n", id->touch_mode ? "ON" : "OFF");
+}
+
+static void
+device_added (GdkDeviceManager *dm, GdkDevice *device, IndicatorData *id)
+{
+  if (id->autodetect)
+    update_touch_mode (id, !has_mouse (dm));
+}
+
+static void
+device_removed (GdkDeviceManager *dm, GdkDevice *device, IndicatorData *id)
+{
+  if (id->autodetect)
+    {
+      /* We need to work around the fact that ::device-removed is emitted
+       * before the device is removed from the list.
+       */
+      g_object_set_data (G_OBJECT (device), "removed", GINT_TO_POINTER (1));
+      update_touch_mode (id, !has_mouse (dm));
+    }
+}
+
+static void
+mode_changed (GtkComboBox *combo, IndicatorData *id)
+{
+  GdkDeviceManager *dm;
+  gint active = gtk_combo_box_get_active (combo);
+
+  dm = gdk_display_get_device_manager (gdk_display_get_default ());
+  if (active == 0)
+    {
+      id->autodetect = TRUE;
+      update_touch_mode (id, !has_mouse (dm));
+    }
+  else if (active == 1)
+    {
+      id->autodetect = FALSE;
+      update_touch_mode (id, FALSE);
+    }
+  else
+    {
+      id->autodetect = FALSE;
+      update_touch_mode (id, TRUE);
+    }
+}
+
+static gchar *
+get_content (void)
+{
+  GString *s;
+  gint i;
+
+  s = g_string_new ("");
+  for (i = 1; i <= 150; i++)
+    g_string_append_printf (s, "Line %d\n", i);
+
+  return g_string_free (s, FALSE);
+}
+
+static const gchar data[] =
+  ".scrollbar.overlay-indicator.dragging,"
+  ".scrollbar.overlay-indicator.locked {"
+  "   -GtkRange-slider-width: 15;"
+  "}"
+  ".scrollbar.overlay-indicator.dragging.trough,"
+  ".scrollbar.overlay-indicator.locked.trough {"
+  "   background-color: alpha(black,0.1);"
+  "}"
+  ".scrollbar.overlay-indicator {"
+  "   -GtkRange-slider-width: 10;"
+  "}"
+  ".scrollbar.overlay-indicator.trough {"
+  "   background-color: transparent;"
+  "}";
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *window;
+  gchar *content;
+  GtkWidget *box;
+  GtkWidget *sw;
+  GtkWidget *tv;
+  GtkWidget *ov;
+  GtkWidget *rv;
+  GtkWidget *sb;
+  GtkWidget *sb2;
+  GtkWidget *combo;
+  GtkAdjustment *adj;
+  GtkCssProvider *provider;
+  IndicatorData *id;
+  GdkDeviceManager *dm;
+
+  gtk_init (&argc, &argv);
+
+  provider = gtk_css_provider_new ();
+  gtk_css_provider_load_from_data (provider, data, -1, NULL);
+  gtk_style_context_add_provider_for_screen (gdk_screen_get_default (),
+                                             GTK_STYLE_PROVIDER (provider),
+                                             GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_default_size (GTK_WINDOW (window), 640, 480);
+  g_signal_connect (window, "delete-event", G_CALLBACK (gtk_main_quit), NULL);
+
+  box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 20);
+  gtk_container_add (GTK_CONTAINER (window), box);
+
+  ov = gtk_overlay_new ();
+  gtk_box_pack_start (GTK_BOX (box), ov, TRUE, TRUE, 0);
+
+  sw = gtk_scrolled_window_new (NULL, NULL);
+  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
+                                  GTK_POLICY_NEVER,
+                                  GTK_POLICY_EXTERNAL);
+
+  gtk_container_add (GTK_CONTAINER (ov), sw);
+
+  content = get_content ();
+
+  tv = gtk_text_view_new ();
+  gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (tv), GTK_WRAP_WORD);
+  gtk_container_add (GTK_CONTAINER (sw), tv);
+  gtk_text_buffer_set_text (gtk_text_view_get_buffer (GTK_TEXT_VIEW (tv)),
+                            content, -1);
+  g_free (content);
+
+  adj = gtk_scrollable_get_vadjustment (GTK_SCROLLABLE (tv));
+
+  sb = gtk_scrollbar_new (GTK_ORIENTATION_VERTICAL, adj);
+
+  rv = gtk_revealer_new ();
+  gtk_revealer_set_transition_type (GTK_REVEALER (rv), GTK_REVEALER_TRANSITION_TYPE_CROSSFADE);
+  gtk_revealer_set_transition_duration (GTK_REVEALER (rv), 750);
+  gtk_container_add (GTK_CONTAINER (rv), sb);
+  gtk_overlay_add_overlay (GTK_OVERLAY (ov), rv);
+  gtk_widget_set_halign (rv, GTK_ALIGN_END);
+  gtk_widget_set_valign (rv, GTK_ALIGN_FILL);
+
+  id = get_indicator_data (sb);
+  id->sw = sw;
+  id->rv = rv;
+
+  gtk_style_context_add_class (gtk_widget_get_style_context (sb), "overlay-indicator");
+  g_signal_connect (sb, "enter-notify-event", G_CALLBACK (enter_notify), NULL);
+  g_signal_connect (sb, "leave-notify-event", G_CALLBACK (leave_notify), NULL);
+  g_signal_connect (gtk_widget_get_style_context (sb), "changed", G_CALLBACK (style_changed), sb);
+  g_signal_connect (adj, "value-changed", G_CALLBACK (value_changed), sb);
+  g_timeout_add (500, conceil_scrollbar, sb);
+
+  combo = gtk_combo_box_text_new ();
+  gtk_widget_set_valign (combo, GTK_ALIGN_START);
+  gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "Autodetect");
+  gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "Mouse mode");
+  gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "Touch mode");
+  g_signal_connect (combo, "changed", G_CALLBACK (mode_changed), id);
+  gtk_combo_box_set_active (GTK_COMBO_BOX (combo), 0);
+
+  gtk_container_add (GTK_CONTAINER (box), combo);
+
+  sb2 = gtk_scrollbar_new (GTK_ORIENTATION_VERTICAL, adj);
+  gtk_container_add (GTK_CONTAINER (box), sb2);
+
+  gtk_widget_show_all (window);
+
+  dm = gdk_display_get_device_manager (gdk_display_get_default ());
+  list_devices (dm);
+
+  g_signal_connect (dm, "device-added", G_CALLBACK (device_added), id);
+  g_signal_connect (dm, "device-removed", G_CALLBACK (device_removed), id);
+
+  gtk_main ();
+
+  return 0;
+}