From bfa2e6725e68881d92a486ab1ab1657046f4fffd Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Sat, 20 May 2023 08:24:11 -0400
Subject: [PATCH] gridview: Add some helpers

Add helper functions to get the section of
an item and to computes the column for an
item, based on sections and the current number
of columns.
---
 gtk/gtkgridview.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/gtk/gtkgridview.c b/gtk/gtkgridview.c
index 6d3dec22eb..b9ad272d01 100644
--- a/gtk/gtkgridview.c
+++ b/gtk/gtkgridview.c
@@ -30,6 +30,7 @@
 #include "gtkmultiselection.h"
 #include "gtktypebuiltins.h"
 #include "gtkwidgetprivate.h"
+#include "gtksectionmodel.h"
 
 /* Maximum number of list items created by the gridview.
  * For debugging, you can set this to G_MAXUINT to ensure
@@ -434,6 +435,51 @@ gtk_grid_view_get_allocation (GtkListBase  *base,
   return TRUE;
 }
 
+/* Returns the section that position falls into
+ */
+static void
+get_section_for_position (GtkGridView  *self,
+                          unsigned int  position,
+                          unsigned int *section_start,
+                          unsigned int *section_end)
+{
+  GListModel *model;
+  unsigned int start, end;
+
+  model = G_LIST_MODEL (gtk_list_item_manager_get_model (self->item_manager));
+
+  if (!gtk_list_item_manager_get_has_sections (self->item_manager))
+    {
+      start = 0;
+      end = g_list_model_get_n_items (model);
+    }
+  else
+    {
+      gtk_section_model_get_section (GTK_SECTION_MODEL (model), position, &start, &end);
+    }
+
+  if (section_start)
+    *section_start = start;
+  if (section_end)
+    *section_end = end;
+}
+
+/* Returns the column that the given item will fall in, taking
+ * sections into account. Note that this depends on whether
+ * we are currently showing sections, and on the number of
+ * columns that the grid is allocating.
+ */
+static unsigned int
+get_column_for_position (GtkGridView  *self,
+                         unsigned int  position)
+{
+  unsigned int start;
+
+  get_section_for_position (self, position, &start, NULL);
+
+  return (position - start) % self->n_columns;
+}
+
 static gboolean
 gtk_grid_view_get_position_from_allocation (GtkListBase           *base,
                                             int                    x,