"""
Routines to assist in plotting
"""

def annotate_width(ax, name, x1, x2, y, text_kw={}, arrow_kw={}):
    default_arrow_kw = dict(
            xy = (x1, y),
            xytext = (x2,y),
            arrowprops = dict(
                arrowstyle="<->",
                shrinkA=False,
                shrinkB=False
            ),
    )

    default_text_kw = dict(
            va='bottom',
            ha='center',
            xy=((x1+x2)/2, y)
    )

    an1 = ax.annotate("", **{**default_arrow_kw, **arrow_kw})
    an2 = ax.annotate(name, **{**default_text_kw, **text_kw})

    return [an1, an2]