[gnome-photos] preview-nav-buttons: Toggle the controls when the user taps

[Debarshi Ray <debarshir src gnome org>]

commit b3ed6640d3cd2ef9052b9fa18e515b1c9c515380
Author: Debarshi Ray <debarshir gnome org>
Date:   Sun Mar 1 00:45:28 2015 +0100

    preview-nav-buttons: Toggle the controls when the user taps
    
    Tapping on a touchscreen will toggle the visibility of the overlaid
    controls without using an auto-hide timeout. The timeout is only used
    when interacting with the mouse. Moving the mouse will continue to
    reveal the controls and auto-hide them based on a timeout, as before.
    
    To make the mouse and touchscreen interactions work together, the
    queueing and unqueing of the timeout has been split out and used
    explicitly where they are needed. An additional variable has been
    introduced to control the visibility of the controls based on internal
    conditions, as opposed to requests from external client code.

 src/photos-preview-nav-buttons.c |  113 +++++++++++++++++++++++++-------------
 1 files changed, 74 insertions(+), 39 deletions(-)
---
diff --git a/src/photos-preview-nav-buttons.c b/src/photos-preview-nav-buttons.c
index bbe39ef..80c8f55 100644
--- a/src/photos-preview-nav-buttons.c
+++ b/src/photos-preview-nav-buttons.c
@@ -39,6 +39,7 @@
 
 struct _PhotosPreviewNavButtonsPrivate
 {
+  GtkGesture *tap_gesture;
   GtkTreeModel *model;
   GtkTreePath *current_path;
   GtkWidget *next_widget;
@@ -49,8 +50,8 @@ struct _PhotosPreviewNavButtonsPrivate
   PhotosPreviewAction action;
   gboolean enable_next;
   gboolean enable_prev;
-  gboolean hover;
   gboolean visible;
+  gboolean visible_internal;
   guint auto_hide_id;
   guint motion_id;
 };
@@ -114,14 +115,45 @@ photos_preview_nav_buttons_fade_out_button (PhotosPreviewNavButtons *self, GtkWi
 }
 
 
+static void
+photos_preview_nav_buttons_update_visibility (PhotosPreviewNavButtons *self)
+{
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+  GtkTreeIter iter;
+  GtkTreeIter tmp;
+  gboolean enable_next = FALSE;
+  gboolean enable_prev = FALSE;
+
+  if (priv->model == NULL
+      || priv->current_path == NULL
+      || !priv->visible
+      || !priv->visible_internal
+      || !gtk_tree_model_get_iter (priv->model, &iter, priv->current_path))
+    {
+      enable_prev = FALSE;
+      enable_next = FALSE;
+      goto out;
+    }
+
+  tmp = iter;
+  enable_prev = gtk_tree_model_iter_previous (priv->model, &tmp);
+
+  tmp = iter;
+  enable_next = gtk_tree_model_iter_next (priv->model, &tmp);
+
+ out:
+  g_object_set (self, "enable-next", enable_next, "enable-previous", enable_prev, NULL);
+}
+
+
 static gboolean
 photos_preview_nav_buttons_auto_hide (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
-  photos_preview_nav_buttons_fade_out_button (self, priv->prev_widget);
-  photos_preview_nav_buttons_fade_out_button (self, priv->next_widget);
   priv->auto_hide_id = 0;
+  priv->visible_internal = FALSE;
+  photos_preview_nav_buttons_update_visibility (self);
   return G_SOURCE_REMOVE;
 }
 
@@ -142,7 +174,6 @@ photos_preview_nav_buttons_unqueue_auto_hide (PhotosPreviewNavButtons *self)
 static gboolean
 photos_preview_nav_buttons_enter_notify (PhotosPreviewNavButtons *self)
 {
-  self->priv->hover = TRUE;
   photos_preview_nav_buttons_unqueue_auto_hide (self);
   return FALSE;
 }
@@ -165,50 +196,20 @@ photos_preview_nav_buttons_queue_auto_hide (PhotosPreviewNavButtons *self)
 static gboolean
 photos_preview_nav_buttons_leave_notify (PhotosPreviewNavButtons *self)
 {
-  self->priv->hover = FALSE;
   photos_preview_nav_buttons_queue_auto_hide (self);
   return FALSE;
 }
 
 
-static void
-photos_preview_nav_buttons_update_visibility (PhotosPreviewNavButtons *self)
-{
-  PhotosPreviewNavButtonsPrivate *priv = self->priv;
-  GtkTreeIter iter;
-  GtkTreeIter tmp;
-  gboolean enable_next = FALSE;
-  gboolean enable_prev = FALSE;
-
-  if (priv->model == NULL
-      || priv->current_path == NULL
-      || !priv->visible
-      || !gtk_tree_model_get_iter (priv->model, &iter, priv->current_path))
-    {
-      enable_prev = FALSE;
-      enable_next = FALSE;
-      goto out;
-    }
-
-  tmp = iter;
-  enable_prev = gtk_tree_model_iter_previous (priv->model, &tmp);
-
-  tmp = iter;
-  enable_next = gtk_tree_model_iter_next (priv->model, &tmp);
-
-  if (!priv->hover)
-    photos_preview_nav_buttons_queue_auto_hide (self);
-
- out:
-  g_object_set (self, "enable-next", enable_next, "enable-previous", enable_prev, NULL);
-}
-
-
 static gboolean
 photos_preview_nav_buttons_motion_notify_timeout (PhotosPreviewNavButtons *self)
 {
-  self->priv->motion_id = 0;
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+
+  priv->motion_id = 0;
+  priv->visible_internal = TRUE;
   photos_preview_nav_buttons_update_visibility (self);
+  photos_preview_nav_buttons_queue_auto_hide (self);
   return G_SOURCE_REMOVE;
 }
 
@@ -237,6 +238,25 @@ photos_preview_nav_buttons_motion_notify (PhotosPreviewNavButtons *self, GdkEven
 
 
 static void
+photos_preview_nav_buttons_multi_press_released (PhotosPreviewNavButtons *self)
+{
+  PhotosPreviewNavButtonsPrivate *priv = self->priv;
+
+  gtk_gesture_set_state (GTK_GESTURE (priv->tap_gesture), GTK_EVENT_SEQUENCE_CLAIMED);
+  priv->visible_internal = !priv->visible_internal;
+  photos_preview_nav_buttons_unqueue_auto_hide (self);
+  photos_preview_nav_buttons_update_visibility (self);
+}
+
+
+static void
+photos_preview_nav_buttons_multi_press_stopped (PhotosPreviewNavButtons *self)
+{
+  gtk_gesture_set_state (GTK_GESTURE (self->priv->tap_gesture), GTK_EVENT_SEQUENCE_DENIED);
+}
+
+
+static void
 photos_preview_nav_buttons_notify_enable_next (PhotosPreviewNavButtons *self)
 {
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
@@ -290,6 +310,7 @@ photos_preview_nav_buttons_dispose (GObject *object)
   PhotosPreviewNavButtons *self = PHOTOS_PREVIEW_NAV_BUTTONS (object);
   PhotosPreviewNavButtonsPrivate *priv = self->priv;
 
+  g_clear_object (&priv->tap_gesture);
   g_clear_object (&priv->model);
   g_clear_object (&priv->overlay);
   g_clear_object (&priv->preview_view);
@@ -384,6 +405,17 @@ photos_preview_nav_buttons_constructed (GObject *object)
                             "motion-notify-event",
                             G_CALLBACK (photos_preview_nav_buttons_motion_notify),
                             self);
+
+  priv->tap_gesture = gtk_gesture_multi_press_new (priv->preview_view);
+  gtk_gesture_single_set_touch_only (GTK_GESTURE_SINGLE (priv->tap_gesture), TRUE);
+  g_signal_connect_swapped (priv->tap_gesture,
+                            "released",
+                            G_CALLBACK (photos_preview_nav_buttons_multi_press_released),
+                            self);
+  g_signal_connect_swapped (priv->tap_gesture,
+                            "stopped",
+                            G_CALLBACK (photos_preview_nav_buttons_multi_press_stopped),
+                            self);
 }
 
 
@@ -546,6 +578,7 @@ photos_preview_nav_buttons_hide (PhotosPreviewNavButtons *self)
 
   priv->action = PHOTOS_PREVIEW_ACTION_NONE;
   priv->visible = FALSE;
+  priv->visible_internal = FALSE;
   photos_preview_nav_buttons_update_visibility (self);
 
   g_signal_emit (self, signals[ACTIVATED], 0, priv->action);
@@ -609,7 +642,9 @@ photos_preview_nav_buttons_show (PhotosPreviewNavButtons *self)
 
   priv->action = PHOTOS_PREVIEW_ACTION_NONE;
   priv->visible = TRUE;
+  priv->visible_internal = TRUE;
   photos_preview_nav_buttons_update_visibility (self);
+  photos_preview_nav_buttons_queue_auto_hide (self);
 
   g_signal_emit (self, signals[ACTIVATED], 0, priv->action);
 }