2003-02-20  Michael Natterer  <mitch@gimp.org>

	Reimplemented the undo history:

	* app/Makefile.am
	* app/undo_history.[ch]: removed.

	Changes/cleanups to the undo system to enable/simplify the new
	undo history implementation:

	* app/core/core-types.h: removed enum undo_event_t. Removed the
	GimpImage parameter from GimpUndoPopFunc and GimpUndoFreeFunc
	because GimpUndo has a GimpImage pointer now (see below).

	* app/core/core-enums.[ch]: added enum GimpUndoEvent. Added an
	enum value for REDO_EXPIRED.

	* app/core/gimpimage.[ch]: added a GimpUndo pointer to the
	"undo_event" signal which needs to be passed for all events except
	UNDO_FREE.

	* app/display/gimpdisplayshell-handlers.c: changed accordingly.

	* app/core/gimpundo.[ch]: added a GimpImage pointer to the
	GimpUndo struct. Removed GimpImage parameters all over the
	place. Added preview stuff. The preview creation needs to be
	triggered explicitly using gimp_undo_create_preview() because the
	GimpUndo can't know when it's possible to create the preview.

	* app/core/gimpimage-undo-push.c
	* app/paint/gimppaintcore-undo.c
	* app/tools/gimptransformtool-undo.c: changed accordingly, cleanup.

	* app/core/gimpundostack.[ch]: ditto. Return the freed undo from
	gimp_undo_stack_free_bottom(). Removed unused container signal
	handlers.

	* app/core/gimpimage-undo.c: free the redo stack the same way old
	undos are freed (from bottom up). Emit "undo_event" with event ==
	REDO_EXPIRED for each removed redo.

	* app/core/gimpmarshal.list: added new marshallers.

	New undo history implementation:

	* app/widgets/Makefile.am
	* app/widgets/widgets-types.h
	* app/widgets/gimpundoeditor.[ch]
	* app/widgets/gimpundopreview.[ch]: new widgets for the undo
	step previews and the history itself.

	* app/widgets/gimppreview-utils.c: added GimpUndoPreview to the
	list of possible preview types.

	* app/gui/dialogs-constructors.[ch]
	* app/gui/dialogs-menu.c
	* app/gui/dialogs.c
	* app/gui/image-menu.c
	* app/gui/toolbox-menu.c: removed the old and added the new undo
	history to the dialog factory and the various dialog menus.

	* app/widgets/gimpdnd.[ch]: don't warn if a GType has no
	corresponding DND type. Instead, return FALSE from the function
	that failed.

	* app/widgets/gimppreview.c: check the return value of gimpdnd
	functions.  Not only add drag sources but also remove them when no
	longer needed.

	* app/widgets/gimpselectioneditor.h: removed unneeded inclusion of
	"gui/gui-types.h".