[gtk+] GtkStack: Add position-dependent slide transitions

[Alexander Larsson <alexl src gnome org>]

commit 33a1c4d6e03bbe2c0eee7b3ce4b8f26e848ae1cb
Author: Erick Pérez Castellanos <erick red gmail com>
Date:   Thu Jun 13 20:33:42 2013 +0200

    GtkStack: Add position-dependent slide transitions
    
    These go left/right or up/down depending on the relative
    order of the children being switched between.

 gtk/gtkstack.c    |   33 +++++++++++++++++++++++++++++++++
 gtk/gtkstack.h    |    4 +++-
 tests/teststack.c |    2 ++
 3 files changed, 38 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkstack.c b/gtk/gtkstack.c
index e890610..fcaa0b2 100644
--- a/gtk/gtkstack.c
+++ b/gtk/gtkstack.c
@@ -56,6 +56,8 @@
  * @GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT: Slide from right to left
  * @GTK_STACK_TRANSITION_TYPE_SLIDE_UP: Slide from bottom up
  * @GTK_STACK_TRANSITION_TYPE_SLIDE_DOWN: Slide from top down
+ * @GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT: Slide from left or right according to the children order
+ * @GTK_STACK_TRANSITION_TYPE_SLIDE_UP_DOWN: Slide from top down or bottom up according to the order
  *
  * These enumeration values describe the possible transitions
  * between pages in a #GtkStack widget.
@@ -870,6 +872,37 @@ set_visible_child (GtkStack               *stack,
   if (child_info)
     gtk_widget_set_child_visible (child_info->widget, TRUE);
 
+  if ((child_info == NULL || priv->last_visible_child == NULL) &&
+      (transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT ||
+       transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_UP_DOWN))
+    {
+      transition_type = GTK_STACK_TRANSITION_TYPE_NONE;
+    }
+  else if (transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT ||
+          transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_UP_DOWN)
+    {
+      gboolean i_first = FALSE;
+      for (l = priv->children; l != NULL; l = g_list_next (l))
+        {
+         if (child_info == l->data)
+           {
+             i_first = TRUE;
+             break;
+           }
+         if (priv->last_visible_child == l->data)
+           break;
+        }
+
+      if (transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT)
+       {
+         transition_type = i_first ? GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT : 
GTK_STACK_TRANSITION_TYPE_SLIDE_RIGHT;
+       }
+      if (transition_type == GTK_STACK_TRANSITION_TYPE_SLIDE_UP_DOWN)
+       {
+         transition_type = i_first ? GTK_STACK_TRANSITION_TYPE_SLIDE_UP : 
GTK_STACK_TRANSITION_TYPE_SLIDE_DOWN;
+       }
+    }
+
   gtk_widget_queue_resize (GTK_WIDGET (stack));
   gtk_widget_queue_draw (GTK_WIDGET (stack));
 
diff --git a/gtk/gtkstack.h b/gtk/gtkstack.h
index 38824e1..baff1cd 100644
--- a/gtk/gtkstack.h
+++ b/gtk/gtkstack.h
@@ -44,7 +44,9 @@ typedef enum {
   GTK_STACK_TRANSITION_TYPE_SLIDE_RIGHT,
   GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT,
   GTK_STACK_TRANSITION_TYPE_SLIDE_UP,
-  GTK_STACK_TRANSITION_TYPE_SLIDE_DOWN
+  GTK_STACK_TRANSITION_TYPE_SLIDE_DOWN,
+  GTK_STACK_TRANSITION_TYPE_SLIDE_LEFT_RIGHT,
+  GTK_STACK_TRANSITION_TYPE_SLIDE_UP_DOWN
 } GtkStackTransitionType;
 
 struct _GtkStack {
diff --git a/tests/teststack.c b/tests/teststack.c
index 0befd8d..3853af2 100644
--- a/tests/teststack.c
+++ b/tests/teststack.c
@@ -215,6 +215,8 @@ main (gint argc,
   gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "SLIDE_LEFT");
   gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "SLIDE_UP");
   gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "SLIDE_DOWN");
+  gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "SLIDE_LEFT_RIGHT");
+  gtk_combo_box_text_append_text (GTK_COMBO_BOX_TEXT (combo), "SLIDE_UP_DOWN");
   gtk_combo_box_set_active (GTK_COMBO_BOX (combo), 0);
 
   gtk_container_add (GTK_CONTAINER (hbox), combo);