from matplotlib.transforms import Bbox, TransformedBbox, \
     blended_transform_factory

from mpl_toolkits.axes_grid1.inset_locator import BboxPatch, BboxConnector,\
     BboxConnectorPatch


def connect_bbox(bbox1, bbox2,
                 loc1a, loc2a, loc1b, loc2b,
                 prop_lines, prop_patches=None):
    if prop_patches is None:
        prop_patches = prop_lines.copy()
        prop_patches["alpha"] = prop_patches.get("alpha", 1)*0.2

    c1 = BboxConnector(bbox1, bbox2, loc1=loc1a, loc2=loc2a, **prop_lines)
    c1.set_clip_on(False)
    c2 = BboxConnector(bbox1, bbox2, loc1=loc1b, loc2=loc2b, **prop_lines)
    c2.set_clip_on(False)

    bbox_patch1 = BboxPatch(bbox1, **prop_patches)
    bbox_patch2 = BboxPatch(bbox2, **prop_patches)

    p = BboxConnectorPatch(bbox1, bbox2,
                           #loc1a=3, loc2a=2, loc1b=4, loc2b=1,
                           loc1a=loc1a, loc2a=loc2a, loc1b=loc1b, loc2b=loc2b,
                           **prop_patches)
    p.set_clip_on(False)

    return c1, c2, bbox_patch1, bbox_patch2, p


def zoom_effect01(ax1, ax2, xmin, xmax, **kwargs):
    u"""
    ax1 : the main axes
    ax1 : the zoomed axes
    (xmin,xmax) : the limits of the colored area in both plot axes.

    connect ax1 & ax2. The x-range of (xmin, xmax) in both axes will
    be marked.  The keywords parameters will be used ti create
    patches.

    """

    trans1 = blended_transform_factory(ax1.transData, ax1.transAxes)
    trans2 = blended_transform_factory(ax2.transData, ax2.transAxes)

    bbox = Bbox.from_extents(xmin, 0, xmax, 1)

    mybbox1 = TransformedBbox(bbox, trans1)
    mybbox2 = TransformedBbox(bbox, trans2)

    prop_patches=kwargs.copy()
    prop_patches["ec"]="none"
    prop_patches["alpha"]=0.2

    c1, c2, bbox_patch1, bbox_patch2, p = \
        connect_bbox(mybbox1, mybbox2,
                     loc1a=3, loc2a=2, loc1b=4, loc2b=1,
                     prop_lines=kwargs, prop_patches=prop_patches)

    ax1.add_patch(bbox_patch1)
    ax2.add_patch(bbox_patch2)
    ax2.add_patch(c1)
    ax2.add_patch(c2)
    ax2.add_patch(p)

    return c1, c2, bbox_patch1, bbox_patch2, p


def zoom_effect02(ax1, ax2, **kwargs):
    u"""
    ax1 : the main axes
    ax1 : the zoomed axes

    Similar to zoom_effect01.  The xmin & xmax will be taken from the
    ax1.viewLim.
    """

    tt = ax1.transScale + (ax1.transLimits + ax2.transAxes)
    trans = blended_transform_factory(ax2.transData, tt)

    mybbox1 = ax1.bbox
    mybbox2 = TransformedBbox(ax1.viewLim, trans)

    prop_patches=kwargs.copy()
    prop_patches["ec"]="none"
    prop_patches["alpha"]=0.2

    c1, c2, bbox_patch1, bbox_patch2, p = \
        connect_bbox(mybbox1, mybbox2,
                     loc1a=3, loc2a=2, loc1b=4, loc2b=1,
                     prop_lines=kwargs, prop_patches=prop_patches)

    ax1.add_patch(bbox_patch1)
    ax2.add_patch(bbox_patch2)
    ax2.add_patch(c1)
    ax2.add_patch(c2)
    ax2.add_patch(p)

    return c1, c2, bbox_patch1, bbox_patch2, p


import matplotlib.pyplot as plt

plt.figure(1, figsize=(5,5))
ax1 = plt.subplot(221)
ax2 = plt.subplot(212)
ax2.set_xlim(0, 1)
ax2.set_xlim(0, 5)
zoom_effect01(ax1, ax2, 0.2, 0.8)


ax1 = plt.subplot(222)
ax1.set_xlim(2, 3)
ax2.set_xlim(0, 5)
zoom_effect02(ax1, ax2)

plt.show()
