355 lines
11 KiB
C
355 lines
11 KiB
C
/* gtktreednd.c
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* Copyright (C) 2001 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include <string.h>
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#include "gtktreednd.h"
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#include "gtkintl.h"
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/**
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* SECTION:gtktreednd
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* @Short_description: Interfaces for drag-and-drop support in GtkTreeView
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* @Title: GtkTreeView drag-and-drop
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*
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* GTK+ supports Drag-and-Drop in tree views with a high-level and a low-level
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* API.
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*
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* The low-level API consists of the GTK+ DND API, augmented by some treeview
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* utility functions: gtk_tree_view_set_drag_dest_row(),
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* gtk_tree_view_get_drag_dest_row(), gtk_tree_view_get_dest_row_at_pos(),
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* gtk_tree_view_create_row_drag_icon(), gtk_tree_set_row_drag_data() and
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* gtk_tree_get_row_drag_data(). This API leaves a lot of flexibility, but
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* nothing is done automatically, and implementing advanced features like
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* hover-to-open-rows or autoscrolling on top of this API is a lot of work.
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*
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* On the other hand, if you write to the high-level API, then all the
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* bookkeeping of rows is done for you, as well as things like hover-to-open
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* and auto-scroll, but your models have to implement the
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* #GtkTreeDragSource and #GtkTreeDragDest interfaces.
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*/
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GType
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gtk_tree_drag_source_get_type (void)
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{
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static GType our_type = 0;
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if (!our_type)
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{
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const GTypeInfo our_info =
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{
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sizeof (GtkTreeDragSourceIface), /* class_size */
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NULL, /* base_init */
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NULL, /* base_finalize */
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NULL,
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NULL, /* class_finalize */
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NULL, /* class_data */
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0,
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0, /* n_preallocs */
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NULL
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};
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our_type = g_type_register_static (G_TYPE_INTERFACE,
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I_("GtkTreeDragSource"),
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&our_info, 0);
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}
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return our_type;
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}
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GType
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gtk_tree_drag_dest_get_type (void)
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{
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static GType our_type = 0;
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if (!our_type)
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{
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const GTypeInfo our_info =
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{
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sizeof (GtkTreeDragDestIface), /* class_size */
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NULL, /* base_init */
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NULL, /* base_finalize */
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NULL,
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NULL, /* class_finalize */
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NULL, /* class_data */
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0,
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0, /* n_preallocs */
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NULL
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};
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our_type = g_type_register_static (G_TYPE_INTERFACE, I_("GtkTreeDragDest"), &our_info, 0);
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}
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return our_type;
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}
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/**
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* gtk_tree_drag_source_row_draggable:
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* @drag_source: a #GtkTreeDragSource
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* @path: row on which user is initiating a drag
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*
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* Asks the #GtkTreeDragSource whether a particular row can be used as
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* the source of a DND operation. If the source doesn’t implement
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* this interface, the row is assumed draggable.
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*
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* Returns: %TRUE if the row can be dragged
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**/
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gboolean
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gtk_tree_drag_source_row_draggable (GtkTreeDragSource *drag_source,
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GtkTreePath *path)
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{
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GtkTreeDragSourceIface *iface = GTK_TREE_DRAG_SOURCE_GET_IFACE (drag_source);
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g_return_val_if_fail (path != NULL, FALSE);
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if (iface->row_draggable)
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return (* iface->row_draggable) (drag_source, path);
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else
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return TRUE;
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/* Returning TRUE if row_draggable is not implemented is a fallback.
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Interface implementations such as GtkTreeStore and GtkListStore really should
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implement row_draggable. */
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}
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/**
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* gtk_tree_drag_source_drag_data_delete:
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* @drag_source: a #GtkTreeDragSource
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* @path: row that was being dragged
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*
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* Asks the #GtkTreeDragSource to delete the row at @path, because
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* it was moved somewhere else via drag-and-drop. Returns %FALSE
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* if the deletion fails because @path no longer exists, or for
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* some model-specific reason. Should robustly handle a @path no
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* longer found in the model!
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*
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* Returns: %TRUE if the row was successfully deleted
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**/
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gboolean
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gtk_tree_drag_source_drag_data_delete (GtkTreeDragSource *drag_source,
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GtkTreePath *path)
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{
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GtkTreeDragSourceIface *iface = GTK_TREE_DRAG_SOURCE_GET_IFACE (drag_source);
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g_return_val_if_fail (iface->drag_data_delete != NULL, FALSE);
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g_return_val_if_fail (path != NULL, FALSE);
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return (* iface->drag_data_delete) (drag_source, path);
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}
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/**
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* gtk_tree_drag_source_drag_data_get:
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* @drag_source: a #GtkTreeDragSource
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* @path: row that was dragged
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* @selection_data: a #GtkSelectionData to fill with data
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* from the dragged row
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*
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* Asks the #GtkTreeDragSource to fill in @selection_data with a
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* representation of the row at @path. @selection_data->target gives
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* the required type of the data. Should robustly handle a @path no
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* longer found in the model!
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*
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* Returns: %TRUE if data of the required type was provided
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**/
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gboolean
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gtk_tree_drag_source_drag_data_get (GtkTreeDragSource *drag_source,
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GtkTreePath *path,
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GtkSelectionData *selection_data)
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{
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GtkTreeDragSourceIface *iface = GTK_TREE_DRAG_SOURCE_GET_IFACE (drag_source);
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g_return_val_if_fail (iface->drag_data_get != NULL, FALSE);
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g_return_val_if_fail (path != NULL, FALSE);
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g_return_val_if_fail (selection_data != NULL, FALSE);
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return (* iface->drag_data_get) (drag_source, path, selection_data);
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}
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/**
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* gtk_tree_drag_dest_drag_data_received:
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* @drag_dest: a #GtkTreeDragDest
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* @dest: row to drop in front of
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* @selection_data: data to drop
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*
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* Asks the #GtkTreeDragDest to insert a row before the path @dest,
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* deriving the contents of the row from @selection_data. If @dest is
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* outside the tree so that inserting before it is impossible, %FALSE
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* will be returned. Also, %FALSE may be returned if the new row is
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* not created for some model-specific reason. Should robustly handle
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* a @dest no longer found in the model!
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*
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* Returns: whether a new row was created before position @dest
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**/
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gboolean
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gtk_tree_drag_dest_drag_data_received (GtkTreeDragDest *drag_dest,
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GtkTreePath *dest,
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GtkSelectionData *selection_data)
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{
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GtkTreeDragDestIface *iface = GTK_TREE_DRAG_DEST_GET_IFACE (drag_dest);
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g_return_val_if_fail (iface->drag_data_received != NULL, FALSE);
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g_return_val_if_fail (dest != NULL, FALSE);
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g_return_val_if_fail (selection_data != NULL, FALSE);
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return (* iface->drag_data_received) (drag_dest, dest, selection_data);
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}
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/**
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* gtk_tree_drag_dest_row_drop_possible:
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* @drag_dest: a #GtkTreeDragDest
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* @dest_path: destination row
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* @selection_data: the data being dragged
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*
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* Determines whether a drop is possible before the given @dest_path,
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* at the same depth as @dest_path. i.e., can we drop the data in
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* @selection_data at that location. @dest_path does not have to
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* exist; the return value will almost certainly be %FALSE if the
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* parent of @dest_path doesn’t exist, though.
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*
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* Returns: %TRUE if a drop is possible before @dest_path
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**/
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gboolean
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gtk_tree_drag_dest_row_drop_possible (GtkTreeDragDest *drag_dest,
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GtkTreePath *dest_path,
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GtkSelectionData *selection_data)
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{
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GtkTreeDragDestIface *iface = GTK_TREE_DRAG_DEST_GET_IFACE (drag_dest);
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g_return_val_if_fail (iface->row_drop_possible != NULL, FALSE);
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g_return_val_if_fail (selection_data != NULL, FALSE);
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g_return_val_if_fail (dest_path != NULL, FALSE);
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return (* iface->row_drop_possible) (drag_dest, dest_path, selection_data);
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}
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typedef struct _TreeRowData TreeRowData;
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struct _TreeRowData
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{
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GtkTreeModel *model;
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gchar path[4];
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};
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/**
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* gtk_tree_set_row_drag_data:
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* @selection_data: some #GtkSelectionData
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* @tree_model: a #GtkTreeModel
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* @path: a row in @tree_model
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*
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* Sets selection data of target type %GTK_TREE_MODEL_ROW. Normally used
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* in a drag_data_get handler.
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*
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* Returns: %TRUE if the #GtkSelectionData had the proper target type to allow us to set a tree row
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**/
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gboolean
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gtk_tree_set_row_drag_data (GtkSelectionData *selection_data,
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GtkTreeModel *tree_model,
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GtkTreePath *path)
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{
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TreeRowData *trd;
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gchar *path_str;
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gint len;
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gint struct_size;
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g_return_val_if_fail (selection_data != NULL, FALSE);
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g_return_val_if_fail (GTK_IS_TREE_MODEL (tree_model), FALSE);
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g_return_val_if_fail (path != NULL, FALSE);
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if (gtk_selection_data_get_target (selection_data) != gdk_atom_intern_static_string ("GTK_TREE_MODEL_ROW"))
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return FALSE;
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path_str = gtk_tree_path_to_string (path);
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len = strlen (path_str);
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/* the old allocate-end-of-struct-to-hold-string trick */
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struct_size = sizeof (TreeRowData) + len + 1 -
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(sizeof (TreeRowData) - G_STRUCT_OFFSET (TreeRowData, path));
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trd = g_malloc (struct_size);
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strcpy (trd->path, path_str);
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g_free (path_str);
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trd->model = tree_model;
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gtk_selection_data_set (selection_data,
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gdk_atom_intern_static_string ("GTK_TREE_MODEL_ROW"),
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8, /* bytes */
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(void*)trd,
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struct_size);
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g_free (trd);
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return TRUE;
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}
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/**
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* gtk_tree_get_row_drag_data:
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* @selection_data: a #GtkSelectionData
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* @tree_model: (out): a #GtkTreeModel
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* @path: (out): row in @tree_model
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*
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* Obtains a @tree_model and @path from selection data of target type
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* %GTK_TREE_MODEL_ROW. Normally called from a drag_data_received handler.
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* This function can only be used if @selection_data originates from the same
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* process that’s calling this function, because a pointer to the tree model
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* is being passed around. If you aren’t in the same process, then you'll
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* get memory corruption. In the #GtkTreeDragDest drag_data_received handler,
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* you can assume that selection data of type %GTK_TREE_MODEL_ROW is
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* in from the current process. The returned path must be freed with
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* gtk_tree_path_free().
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*
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* Returns: %TRUE if @selection_data had target type %GTK_TREE_MODEL_ROW and
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* is otherwise valid
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**/
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gboolean
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gtk_tree_get_row_drag_data (GtkSelectionData *selection_data,
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GtkTreeModel **tree_model,
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GtkTreePath **path)
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{
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TreeRowData *trd;
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g_return_val_if_fail (selection_data != NULL, FALSE);
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if (tree_model)
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*tree_model = NULL;
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if (path)
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*path = NULL;
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if (gtk_selection_data_get_target (selection_data) != gdk_atom_intern_static_string ("GTK_TREE_MODEL_ROW"))
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return FALSE;
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if (gtk_selection_data_get_length (selection_data) < 0)
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return FALSE;
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trd = (void*) gtk_selection_data_get_data (selection_data);
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if (tree_model)
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*tree_model = trd->model;
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if (path)
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*path = gtk_tree_path_new_from_string (trd->path);
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return TRUE;
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}
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