def hsva_to_rgba(h, s, v, alpha=1.0):
    """Converts a color given by its HSVA coordinates (hue, saturation,
    value, alpha) to RGB coordinates.

    Each of the HSVA coordinates must be in the range [0, 1].
    """
    c = v * s
    h1 = h * 6 % 6
    x = c * (1 - abs(h1 % 2 - 1))
    m = v - c
    h1 = int(h1)
    if h1 < 3:
        if h1 < 1:
            return c + m, x + m, m, alpha
        elif h1 < 2:
            return x + m, c + m, m, alpha
        else:
            return m, c + m, x + m, alpha
    elif h1 < 4:
        return m, x + m, c + m, alpha
    elif h1 < 5:
        return x + m, m, c + m, alpha
    else:
        return c + m, m, x + m, alpha
