drag_and_drop.py 文件源码

def drag_begin(self, widget, drag_context, data):

        self.dnd_data_received = False

        # get x,y co-ords of source square
        x, y = data

        if gv.verbose:
            print("in drag begin")
            print("data=", data)
            print("widget_name=", widget.get_name())
            print("source sq=", x, y)

        stm = gv.jcchess.get_side_to_move()

        # convert the x, y co-ords into the shogi representation
        # (e.g. 8, 6 is 1g)
        sq = gv.board.get_square_posn(x, y)

        self.src = sq
        if gv.verbose:
            print("source square: (x, y) = (", x, ",",  y, ") ", sq)
        self.src_x = x
        self.src_y = y

        # set the icon for the drag and drop to the piece that is being
        # dragged
        self.piece = gv.board.get_piece(x, y)
        # get width/height of board square
        a = gv.gui.get_event_box(x, y).get_allocation()
        surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, a.width, a.height)
        svghandle = gv.board.get_piece_handle(x, y)
        dim = svghandle.get_dimensions()

        cr = cairo.Context(surface)
        sfw = (a.width * 1.0 / dim.width) * SCALE
        sfh = (a.height * 1.0 / dim.height) * SCALE
        cr.scale(sfw, sfh)

        svghandle.render_cairo(cr)
        # set mouse pointer to be in middle of drag icon
        surface.set_device_offset(-a.width/2, -a.height/2)
        Gtk.drag_set_icon_surface(drag_context, surface)

        # clear the square where the piece is being moved from
        gv.board.set_square_as_unoccupied(x, y)