[nautilus/wip/antoniof/drag-source-changes: 2/3] files-view: Add Drag Source

[António Fernandes <antoniof src gnome org>]

commit f32f718b1d1450754f21d13934c462857e6347b1
Author: Corey Berla <corey berla me>
Date:   Tue May 17 12:52:31 2022 -0700

    files-view: Add Drag Source
    
    Create DragSource and connect to signals.  Use existing functions
    to get the selection and convert to a file list.  Pick the first
    icon for a drag icon.

 src/nautilus-files-view.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
---
diff --git a/src/nautilus-files-view.c b/src/nautilus-files-view.c
index 109d991c2..2b4ff4dfd 100644
--- a/src/nautilus-files-view.c
+++ b/src/nautilus-files-view.c
@@ -4198,6 +4198,47 @@ on_end_file_changes (NautilusFilesView *view)
     }
 }
 
+static GdkContentProvider *
+on_drag_prepare (GtkDragSource     *source,
+                 double             x,
+                 double             y,
+                 NautilusFilesView *self)
+{
+    g_autolist (NautilusFile) selection = NULL;
+    g_autoslist (GFile) file_list = NULL;
+    g_autoptr (GdkPaintable) paintable = NULL;
+    g_autoptr (GtkSnapshot) snapshot = NULL;
+    GdkDragAction actions;
+
+    selection = nautilus_files_view_get_selection (NAUTILUS_VIEW (self));
+    if (selection != NULL)
+    {
+        file_list = convert_file_list_to_gdk_file_list (selection);
+        actions = GDK_ACTION_COPY | GDK_ACTION_LINK | GDK_ACTION_ASK | GDK_ACTION_MOVE;
+        gtk_drag_source_set_actions (source, actions);
+        paintable = nautilus_file_get_icon_paintable (selection->data, NAUTILUS_GRID_ICON_SIZE_LARGE, 1, 0);
+        for (GList *cur_file = selection->next; cur_file != NULL; cur_file = cur_file->next)
+        {
+            g_autoptr (GdkPaintable) paintable2 = NULL;
+            paintable2 = nautilus_file_get_icon_paintable (cur_file->data, NAUTILUS_GRID_ICON_SIZE_LARGE, 1, 
0);
+            if (paintable2 != paintable || cur_file->next == NULL)
+            {
+                snapshot = gtk_snapshot_new ();
+                gdk_paintable_snapshot (paintable, snapshot, NAUTILUS_GRID_ICON_SIZE_LARGE, 
NAUTILUS_GRID_ICON_SIZE_LARGE);
+                gdk_paintable_snapshot (paintable2, snapshot, NAUTILUS_GRID_ICON_SIZE_LARGE * 0.5, 
NAUTILUS_GRID_ICON_SIZE_LARGE * 0.5);
+                g_object_unref (paintable);
+                paintable = gtk_snapshot_to_paintable (snapshot, NULL);
+                break;
+            }
+        }
+
+        gtk_drag_source_set_icon (source, paintable, 0, 0);
+        return gdk_content_provider_new_typed (GDK_TYPE_FILE_LIST, file_list);
+    }
+
+    return NULL;
+}
+
 static int
 compare_pointers (gconstpointer pointer_1,
                   gconstpointer pointer_2)
@@ -9348,6 +9389,7 @@ nautilus_files_view_init (NautilusFilesView *view)
 #endif
     NautilusDirectory *scripts_directory;
     NautilusDirectory *templates_directory;
+    GtkDragSource *drag_source;
     GtkEventController *controller;
     gchar *templates_uri;
     GdkClipboard *clipboard;
@@ -9552,6 +9594,10 @@ nautilus_files_view_init (NautilusFilesView *view)
 
     priv->in_destruction = FALSE;
 
+    drag_source = gtk_drag_source_new ();
+    g_signal_connect (drag_source, "prepare", G_CALLBACK (on_drag_prepare), view);
+    gtk_widget_add_controller (GTK_WIDGET (view), GTK_EVENT_CONTROLLER (drag_source));
+
 #if 0 && NAUTILUS_A11Y_NEEDS_GTK4_REIMPLEMENTATION
     /* Accessibility */
     atk_object = gtk_widget_get_accessible (GTK_WIDGET (view));