def rectangle_props(event):
    """
    Returns the width, height, left, and bottom of a rectangle artist.

    Parameters
    -----------
    event : PickEvent
        The pick event to process

    Returns
    --------
    A dict with keys:
        `width` : The width of the rectangle
        `height` : The height of the rectangle
        `left` : The minimum x-coordinate of the rectangle
        `right` : The maximum x-coordinate of the rectangle
        `bottom` : The minimum y-coordinate of the rectangle
        `top` : The maximum y-coordinate of the rectangle
        `xcenter` : The mean x-coordinate of the rectangle
        `ycenter` : The mean y-coordinate of the rectangle
        `label` : The label for the rectangle or None
    """
    artist = event.artist
    width, height = artist.get_width(), artist.get_height()
    left, bottom = artist.xy
    right, top = left + width, bottom + height
    xcenter = left + 0.5 * width
    ycenter = bottom + 0.5 * height
    label = artist.get_label()
    if label is None or label.startswith('_nolegend'):
        try:
            label = artist._mpldatacursor_label
        except AttributeError:
            label = None
    return dict(width=width, height=height, left=left, bottom=bottom, label
        =label, right=right, top=top, xcenter=xcenter, ycenter=ycenter)
