Craft the URL for a placeholder image.

    You can customize the background color, text color and text using
    the optional keyword arguments

    If you want to use a random color pass in random_background_color as True.

def get_url(
    width, height=None, background_color="cccccc",
    text_color="969696", text=None, random_background_color=False
):
    """
    Craft the URL for a placeholder image.

    You can customize the background color, text color and text using
    the optional keyword arguments

    If you want to use a random color pass in random_background_color as True.
    """
    if random_background_color:
        background_color = _get_random_color()

    # If height is not provided, presume it is will be a square
    if not height:
        height = width
    d = dict(
        width=width,
        height=height,
        bcolor=background_color,
        tcolor=text_color
    )
    url = URL % d
    if text:
        text = text.replace(" ", "+")
        url = url + "?text=" + text
    return url