[gthumb] grid view: show the drop destination even when the list is empty

[Paolo Bacchilega <paobac src gnome org>]

commit b23d95c1de0539a89bc4b11c27bf7b4a2d92f77b
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Mar 20 11:48:39 2022 +0100

    grid view: show the drop destination even when the list is empty

 gthumb/gth-grid-view.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)
---
diff --git a/gthumb/gth-grid-view.c b/gthumb/gth-grid-view.c
index 7d199d89..999c4336 100644
--- a/gthumb/gth-grid-view.c
+++ b/gthumb/gth-grid-view.c
@@ -1650,10 +1650,21 @@ _gth_grid_view_draw_drop_target (GthGridView *self,
        GthGridViewItem *item;
        int              x;
 
-       if ((self->priv->drop_item < 0) || (self->priv->drop_item >= self->priv->n_items))
+       style_context = gtk_widget_get_style_context (GTK_WIDGET (self));
+
+       /* Special case: dropping on an empty list. */
+       if ((self->priv->drop_item == 0) && (self->priv->n_items == 0)) {
+               gtk_render_focus (style_context,
+                                 cr,
+                                 self->priv->cell_padding,
+                                 self->priv->cell_padding,
+                                 2,
+                                 self->priv->cell_size - (self->priv->cell_padding * 2));
                return;
+       }
 
-       style_context = gtk_widget_get_style_context (GTK_WIDGET (self));
+       if ((self->priv->drop_item < 0) || (self->priv->drop_item >= self->priv->n_items))
+               return;
 
        item = g_ptr_array_index (self->priv->itemv, self->priv->drop_item);
 
@@ -1718,11 +1729,11 @@ gth_grid_view_draw (GtkWidget *widget,
 
                if (self->priv->selecting || self->priv->multi_selecting_with_keyboard)
                        _gth_grid_view_draw_rubberband (self, cr);
-
-               if (self->priv->drop_pos != GTH_DROP_POSITION_NONE)
-                       _gth_grid_view_draw_drop_target (self, cr);
        }
 
+       if (self->priv->drop_pos != GTH_DROP_POSITION_NONE)
+               _gth_grid_view_draw_drop_target (self, cr);
+
        cairo_restore (cr);
 
        return TRUE;
@@ -2542,7 +2553,7 @@ gth_grid_view_set_drag_dest_pos (GthFileView    *file_view,
                        drop_pos = GTH_DROP_POSITION_LEFT;
                }
                else if (drop_image >= self->priv->n_items) {
-                       drop_image = self->priv->n_items - 1;
+                       drop_image = (self->priv->n_items > 0) ? self->priv->n_items - 1 : 0;
                        drop_pos = GTH_DROP_POSITION_RIGHT;
                }
                else {