[recipes] cuisine page: Defer scrolling to an idle

[Matthias Clasen <matthiasc src gnome org>]

commit 53a907ccc2948035485a1f87552dd1b33a1504b4
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jan 17 06:40:44 2017 -0500

    cuisine page: Defer scrolling to an idle
    
    This avoids problems when switching between different cuisines.
    We also avoid some unnecessary inefficiency by providing direct
    links from the sidebar items to the content.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=777304

 src/gr-cuisine-page.c |   74 +++++++++++++++++++++++++++----------------------
 1 files changed, 41 insertions(+), 33 deletions(-)
---
diff --git a/src/gr-cuisine-page.c b/src/gr-cuisine-page.c
index 529cc47..b0db1a5 100644
--- a/src/gr-cuisine-page.c
+++ b/src/gr-cuisine-page.c
@@ -53,6 +53,7 @@ struct _GrCuisinePage
         GtkWidget *scrolled_window;
         GtkWidget *category_box;
         GtkWidget *stack;
+        GtkWidget *scroll_to_row;
 
         int n_categories;
         Category *categories;
@@ -63,41 +64,42 @@ G_DEFINE_TYPE (GrCuisinePage, gr_cuisine_page, GTK_TYPE_BOX)
 
 static void connect_store_signals (GrCuisinePage *page);
 
-static void
-row_selected (GrCuisinePage *page,
-              GtkListBoxRow *row)
+static gboolean
+scroll_in_idle (gpointer data)
 {
+        GrCuisinePage *page = data;
         GtkWidget *item;
-        int i;
-        int category;
         GtkAdjustment *adj;
         GtkAllocation alloc;
         double page_increment, value;
+        Category *category;
 
-        if (row == NULL)
-                return;
+        if (page->scroll_to_row == NULL)
+                return G_SOURCE_REMOVE;
 
-        category = -1;
-        item = gtk_bin_get_child (GTK_BIN (row));
-        for (i = 0; i < page->n_categories; i++) {
-                if (page->categories[i].item == item) {
-                        category = i;
-                        break;
-                }
-        }
+        item = gtk_bin_get_child (GTK_BIN (page->scroll_to_row));
+        category = (Category *)g_object_get_data (G_OBJECT (item), "category");
 
-        if (category < 0)
-                return;
+        if (!category)
+                return G_SOURCE_REMOVE;
 
         adj = gtk_scrolled_window_get_vadjustment (GTK_SCROLLED_WINDOW (page->scrolled_window));
-        gtk_widget_get_allocation (page->categories[category].label, &alloc);
+        gtk_widget_get_allocation (category->label, &alloc);
         page_increment = gtk_adjustment_get_page_increment (adj);
         value = gtk_adjustment_get_value (adj);
         gtk_adjustment_set_page_increment (adj, alloc.y - value);
-
         g_signal_emit_by_name (page->scrolled_window, "scroll-child", GTK_SCROLL_PAGE_FORWARD, FALSE);
-
         gtk_adjustment_set_page_increment (adj, page_increment);
+
+        return G_SOURCE_REMOVE;
+}
+
+static void
+row_selected (GrCuisinePage *page,
+              GtkListBoxRow *row)
+{
+        page->scroll_to_row = GTK_WIDGET (row);
+        g_idle_add (scroll_in_idle, page);
 }
 
 static void
@@ -155,6 +157,8 @@ populate_initially (GrCuisinePage *self)
                 self->categories[i].label = label;
                 self->categories[i].box = box;
 
+                g_object_set_data (G_OBJECT (item), "category", &self->categories[i]);
+
                 if (strcmp (names[i], "other") == 0)
                         self->other = &self->categories[i];
         }
@@ -164,16 +168,13 @@ static gboolean
 filter_sidebar (GtkListBoxRow *row,
                 gpointer       user_data)
 {
-        GrCuisinePage *page = user_data;
         GtkWidget *item;
-        int i;
+        Category *category;
 
         item = gtk_bin_get_child (GTK_BIN (row));
-        for (i = 0; i < page->n_categories; i++) {
-                if (page->categories[i].item == item) {
-                        return page->categories[i].filled;
-                }
-        }
+        category = (Category *)g_object_get_data (G_OBJECT (item), "category");
+        if (category)
+                return category->filled;
 
         return TRUE;
 }
@@ -218,6 +219,17 @@ gr_cuisine_page_new (void)
         return GTK_WIDGET (page);
 }
 
+#if 0
+static gboolean
+unselect (gpointer data)
+{
+        GrCuisinePage *self = data;
+
+        gtk_list_box_unselect_all (GTK_LIST_BOX (self->sidebar));
+
+        return G_SOURCE_REMOVE;
+}
+#endif
 void
 gr_cuisine_page_set_cuisine (GrCuisinePage *self,
                              const char    *cuisine)
@@ -276,15 +288,11 @@ gr_cuisine_page_set_cuisine (GrCuisinePage *self,
                 has_recipe = TRUE;
         }
 
-        if (has_recipe) {
-                gtk_stack_set_visible_child_name (GTK_STACK (self->stack), "cuisine");
-        }
-        else {
-                gtk_stack_set_visible_child_name (GTK_STACK (self->stack), "empty");
-        }
+        gtk_stack_set_visible_child_name (GTK_STACK (self->stack), has_recipe ? "cuisine" : "empty");
 
         gtk_list_box_invalidate_filter (GTK_LIST_BOX (self->sidebar));
         gtk_list_box_unselect_all (GTK_LIST_BOX (self->sidebar));
+        //g_idle_add (unselect, self);
 }
 
 static void