[gthumb] grid view: use the thumbnail as drag icon

[Paolo Bacchilega <paobac src gnome org>]

commit 9ba3bfe95adf85c4139949dedfca1d5c349a06e5
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Apr 22 12:07:17 2019 +0200

    grid view: use the thumbnail as drag icon

 gthumb/gth-grid-view.c | 68 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 44 insertions(+), 24 deletions(-)
---
diff --git a/gthumb/gth-grid-view.c b/gthumb/gth-grid-view.c
index 4607189d..55d663ae 100644
--- a/gthumb/gth-grid-view.c
+++ b/gthumb/gth-grid-view.c
@@ -2484,13 +2484,13 @@ gth_grid_view_set_model (GthFileView  *file_view,
 
 
 static int
-gth_grid_view_get_at_position (GthFileView *file_view,
-                              int          x,
-                              int          y)
+_gth_grid_view_get_at_position (GthGridView      *self,
+                               int               x,
+                               int               y,
+                               GthGridViewItem **item_ref)
 {
-       GthGridView *self = GTH_GRID_VIEW (file_view);
-       GList       *scan;
-       int          n;
+       GList *scan;
+       int    n;
 
        for (scan = self->priv->items, n = 0;
             scan != NULL;
@@ -2501,14 +2501,28 @@ gth_grid_view_get_at_position (GthFileView *file_view,
                if (_cairo_rectangle_contains_point (&item->thumbnail_area, x, y)
                    || _cairo_rectangle_contains_point (&item->caption_area, x, y))
                {
+                       if (item_ref != NULL)
+                               *item_ref = item;
                        return n;
                }
        }
 
+       if (item_ref != NULL)
+               *item_ref = NULL;
+
        return -1;
 }
 
 
+static int
+gth_grid_view_get_at_position (GthFileView     *file_view,
+                              int               x,
+                              int               y)
+{
+       return _gth_grid_view_get_at_position (GTH_GRID_VIEW (file_view), x, y, NULL);
+}
+
+
 static void
 gth_grid_view_cursor_changed (GthFileView *file_view,
                              int          pos)
@@ -2828,9 +2842,10 @@ static int
 gth_grid_view_button_press (GtkWidget      *widget,
                            GdkEventButton *event)
 {
-       GthGridView *self = GTH_GRID_VIEW (widget);
-       int          retval = FALSE;
-       int          pos;
+       GthGridView *    self = GTH_GRID_VIEW (widget);
+       int              retval = FALSE;
+       int              pos;
+       GthGridViewItem *item;
 
        if (event->window != self->priv->bin_window)
                return FALSE;
@@ -2838,7 +2853,7 @@ gth_grid_view_button_press (GtkWidget      *widget,
        if (! gtk_widget_has_focus (widget))
                gtk_widget_grab_focus (widget);
 
-       pos = gth_grid_view_get_at_position (GTH_FILE_VIEW (self), event->x, event->y);
+       pos = _gth_grid_view_get_at_position (self, event->x, event->y, &item);
 
        if ((pos != -1) && (event->button == 1) && (event->type == GDK_2BUTTON_PRESS)) {
                /* Double click activates the item */
@@ -2881,9 +2896,6 @@ gth_grid_view_button_press (GtkWidget      *widget,
                }
 
                if (self->priv->selection_mode != GTK_SELECTION_NONE) {
-                       GthGridViewItem *item;
-
-                       item = g_list_nth (self->priv->items, pos)->data;
                        if (self->priv->selection_mode == GTK_SELECTION_MULTIPLE)
                                _gth_grid_view_select_multiple (self, item, pos, event);
                        else
@@ -3175,15 +3187,17 @@ gth_grid_view_motion_notify (GtkWidget      *widget,
                                                 event->x,
                                                 event->y))
                {
-                       int             pos;
-                       GdkDragContext *context;
-                       gboolean        multi_dnd;
+                       GthGridViewItem *item;
+                       int              pos;
+                       GdkDragContext  *context;
+                       gboolean         multi_dnd;
 
                        /**/
 
-                       pos = gth_grid_view_get_at_position (GTH_FILE_VIEW (self),
-                                                            self->priv->drag_start_x,
-                                                            self->priv->drag_start_y);
+                       pos = _gth_grid_view_get_at_position (self,
+                                                             self->priv->drag_start_x,
+                                                             self->priv->drag_start_y,
+                                                             &item);
                        if (pos != -1)
                                gth_file_view_set_cursor (GTH_FILE_VIEW (self), pos);
 
@@ -3202,12 +3216,18 @@ gth_grid_view_motion_notify (GtkWidget      *widget,
                                                                   -1,
                                                                   -1);
 
-                       /* FIXME: create a cool drag icon here */
                        multi_dnd = self->priv->selection->next != NULL;
-                       gtk_drag_set_icon_name (context,
-                                               multi_dnd ? "emblem-documents-symbolic" : 
"folder-documents-symbolic",
-                                               -4,
-                                               -4);
+
+                       if ((pos != -1) && (item != NULL) && (item->thumbnail != NULL)) {
+                               cairo_surface_t *icon = _cairo_create_dnd_icon (item->thumbnail, 
self->priv->thumbnail_size, multi_dnd);
+                               gtk_drag_set_icon_surface (context, icon);
+                               cairo_surface_destroy (icon);
+                       }
+                       else
+                               gtk_drag_set_icon_name (context,
+                                                       multi_dnd ? "emblem-documents-symbolic" : 
"folder-documents-symbolic",
+                                                       -4,
+                                                       -4);
                }
 
                return TRUE;