"""
GUI Neutral widgets
===================

Widgets that are designed to work for any of the GUI backends.
All of these widgets require you to predefine an :class:`matplotlib.axes.Axes`
instance and pass that as the first arg.  matplotlib doesn't try to
be too smart with respect to layout -- you will have to figure out how
wide and tall you want your Axes to be to accommodate your widget.
"""


import numpy as np

from .mlab import dist
from .patches import Circle, Rectangle
from .lines import Line2D
from .transforms import blended_transform_factory


class LockDraw:
    """
    Some widgets, like the cursor, draw onto the canvas, and this is not
    desirable under all circumstances, like when the toolbar is in
    zoom-to-rect mode and drawing a rectangle.  The module level "lock"
    allows someone to grab the lock and prevent other widgets from
    drawing.  Use ``matplotlib.widgets.lock(someobj)`` to pr
    """
    # FIXME: This docstring ends abruptly without...

    def __init__(self):
        self._owner = None

    def __call__(self, o):
        """reserve the lock for *o*"""
        if not self.available(o):
            raise ValueError('already locked')
        self._owner = o

    def release(self, o):
        """release the lock"""
        if not self.available(o):
            raise ValueError('you do not own this lock')
        self._owner = None

    def available(self, o):
        """drawing is available to *o*"""
        return not self.locked() or self.isowner(o)

    def isowner(self, o):
        """Return True if *o* owns this lock"""
        return self._owner is o

    def locked(self):
        """Return True if the lock is currently held by an owner"""
        return self._owner is not None


class Widget(object):
    """
    Abstract base class for GUI neutral widgets
    """
    drawon = True
    eventson = True


class AxesWidget(Widget):
    """Widget that is connected to a single :class:`~matplotlib.axes.Axes`.

    Attributes:

    *ax* : :class:`~matplotlib.axes.Axes`
        The parent axes for the widget
    *canvas* : :class:`~matplotlib.backend_bases.FigureCanvasBase` subclass
        The parent figure canvas for the widget.
    *active* : bool
        If False, the widget does not respond to events.
    """
    def __init__(self, ax):
        self.ax = ax
        self.canvas = ax.figure.canvas
        self.cids = []
        self.active = True

    def connect_event(self, event, callback):
        """Connect callback with an event.

        This should be used in lieu of `figure.canvas.mpl_connect` since this
        function stores call back ids for later clean up.
        """
        cid = self.canvas.mpl_connect(event, callback)
        self.cids.append(cid)

    def disconnect_events(self):
        """Disconnect all events created by this widget."""
        for c in self.cids:
            self.canvas.mpl_disconnect(c)

    def ignore(self, event):
        """Return True if event should be ignored.

        This method (or a version of it) should be called at the beginning
        of any event callback.
        """
        return not self.active


class Button(AxesWidget):
    """
    A GUI neutral button

    The following attributes are accessible

      *ax*
        The :class:`matplotlib.axes.Axes` the button renders into.

      *label*
        A :class:`matplotlib.text.Text` instance.

      *color*
        The color of the button when not hovering.

      *hovercolor*
        The color of the button when hovering.

    Call :meth:`on_clicked` to connect to the button
    """

    def __init__(self, ax, label, image=None,
                 color='0.85', hovercolor='0.95'):
        """
        *ax*
            The :class:`matplotlib.axes.Axes` instance the button
            will be placed into.

        *label*
            The button text. Accepts string.

        *image*
            The image to place in the button, if not *None*.
            Can be any legal arg to imshow (numpy array,
            matplotlib Image instance, or PIL image).

        *color*
            The color of the button when not activated

        *hovercolor*
            The color of the button when the mouse is over it
        """
        AxesWidget.__init__(self, ax)

        if image is not None:
            ax.imshow(image)
        self.label = ax.text(0.5, 0.5, label,
                             verticalalignment='center',
                             horizontalalignment='center',
                             transform=ax.transAxes)

        self.cnt = 0
        self.observers = {}

        self.connect_event('button_press_event', self._click)
        self.connect_event('button_release_event', self._release)
        self.connect_event('motion_notify_event', self._motion)
        ax.set_navigate(False)
        ax.set_axis_bgcolor(color)
        ax.set_xticks([])
        ax.set_yticks([])
        self.color = color
        self.hovercolor = hovercolor

        self._lastcolor = color

    def _click(self, event):
        if self.ignore(event):
            return
        if event.inaxes != self.ax:
            return
        if not self.eventson:
            return
        if event.canvas.mouse_grabber != self.ax:
            event.canvas.grab_mouse(self.ax)

    def _release(self, event):
        if self.ignore(event):
            return
        if event.canvas.mouse_grabber != self.ax:
            return
        event.canvas.release_mouse(self.ax)
        if not self.eventson:
            return
        if event.inaxes != self.ax:
            return
        for cid, func in self.observers.items():
            func(event)

    def _motion(self, event):
        if self.ignore(event):
            return
        if event.inaxes == self.ax:
            c = self.hovercolor
        else:
            c = self.color
        if c != self._lastcolor:
            self.ax.set_axis_bgcolor(c)
            self._lastcolor = c
            if self.drawon:
                self.ax.figure.canvas.draw()

    def on_clicked(self, func):
        """
        When the button is clicked, call this *func* with event

        A connection id is returned which can be used to disconnect
        """
        cid = self.cnt
        self.observers[cid] = func
        self.cnt += 1
        return cid

    def disconnect(self, cid):
        """remove the observer with connection id *cid*"""
        try:
            del self.observers[cid]
        except KeyError:
            pass


class Slider(AxesWidget):
    """
    A slider representing a floating point range

    The following attributes are defined
      *ax*        : the slider :class:`matplotlib.axes.Axes` instance

      *val*       : the current slider value

      *vline*     : a :class:`matplotlib.lines.Line2D` instance
                     representing the initial value of the slider

      *poly*      : A :class:`matplotlib.patches.Polygon` instance
                     which is the slider knob

      *valfmt*    : the format string for formatting the slider text

      *label*     : a :class:`matplotlib.text.Text` instance
                     for the slider label

      *closedmin* : whether the slider is closed on the minimum

      *closedmax* : whether the slider is closed on the maximum

      *slidermin* : another slider - if not *None*, this slider must be
                     greater than *slidermin*

      *slidermax* : another slider - if not *None*, this slider must be
                     less than *slidermax*

      *dragging*  : allow for mouse dragging on slider

    Call :meth:`on_changed` to connect to the slider event
    """
    def __init__(self, ax, label, valmin, valmax, valinit=0.5, valfmt='%1.2f',
                 closedmin=True, closedmax=True, slidermin=None,
                 slidermax=None, dragging=True, **kwargs):
        """
        Create a slider from *valmin* to *valmax* in axes *ax*

        *valinit*
            The slider initial position

        *label*
            The slider label

        *valfmt*
            Used to format the slider value

        *closedmin* and *closedmax*
            Indicate whether the slider interval is closed

        *slidermin* and *slidermax*
            Used to constrain the value of this slider to the values
            of other sliders.

        additional kwargs are passed on to ``self.poly`` which is the
        :class:`matplotlib.patches.Rectangle` which draws the slider
        knob.  See the :class:`matplotlib.patches.Rectangle` documentation
        valid property names (e.g., *facecolor*, *edgecolor*, *alpha*, ...)
        """
        AxesWidget.__init__(self, ax)

        self.valmin = valmin
        self.valmax = valmax
        self.val = valinit
        self.valinit = valinit
        self.poly = ax.axvspan(valmin, valinit, 0, 1, **kwargs)

        self.vline = ax.axvline(valinit, 0, 1, color='r', lw=1)

        self.valfmt = valfmt
        ax.set_yticks([])
        ax.set_xlim((valmin, valmax))
        ax.set_xticks([])
        ax.set_navigate(False)

        self.connect_event('button_press_event', self._update)
        self.connect_event('button_release_event', self._update)
        if dragging:
            self.connect_event('motion_notify_event', self._update)
        self.label = ax.text(-0.02, 0.5, label, transform=ax.transAxes,
                             verticalalignment='center',
                             horizontalalignment='right')

        self.valtext = ax.text(1.02, 0.5, valfmt % valinit,
                               transform=ax.transAxes,
                               verticalalignment='center',
                               horizontalalignment='left')

        self.cnt = 0
        self.observers = {}

        self.closedmin = closedmin
        self.closedmax = closedmax
        self.slidermin = slidermin
        self.slidermax = slidermax
        self.drag_active = False

    def _update(self, event):
        """update the slider position"""
        if self.ignore(event):
            return

        if event.button != 1:
            return

        if event.name == 'button_press_event' and event.inaxes == self.ax:
            self.drag_active = True
            event.canvas.grab_mouse(self.ax)

        if not self.drag_active:
            return

        elif ((event.name == 'button_release_event') or
              (event.name == 'button_press_event' and
               event.inaxes != self.ax)):
            self.drag_active = False
            event.canvas.release_mouse(self.ax)
            return

        val = event.xdata
        if val <= self.valmin:
            if not self.closedmin:
                return
            val = self.valmin
        elif val >= self.valmax:
            if not self.closedmax:
                return
            val = self.valmax

        if self.slidermin is not None and val <= self.slidermin.val:
            if not self.closedmin:
                return
            val = self.slidermin.val

        if self.slidermax is not None and val >= self.slidermax.val:
            if not self.closedmax:
                return
            val = self.slidermax.val

        self.set_val(val)

    def set_val(self, val):
        xy = self.poly.xy
        xy[2] = val, 1
        xy[3] = val, 0
        self.poly.xy = xy
        self.valtext.set_text(self.valfmt % val)
        if self.drawon:
            self.ax.figure.canvas.draw()
        self.val = val
        if not self.eventson:
            return
        for cid, func in self.observers.items():
            func(val)

    def on_changed(self, func):
        """
        When the slider value is changed, call *func* with the new
        slider position

        A connection id is returned which can be used to disconnect
        """
        cid = self.cnt
        self.observers[cid] = func
        self.cnt += 1
        return cid

    def disconnect(self, cid):
        """remove the observer with connection id *cid*"""
        try:
            del self.observers[cid]
        except KeyError:
            pass

    def reset(self):
        """reset the slider to the initial value if needed"""
        if (self.val != self.valinit):
            self.set_val(self.valinit)


class CheckButtons(AxesWidget):
    """
    A GUI neutral radio button

    The following attributes are exposed

     *ax*
        The :class:`matplotlib.axes.Axes` instance the buttons are
        located in

     *labels*
        List of :class:`matplotlib.text.Text` instances

     *lines*
        List of (line1, line2) tuples for the x's in the check boxes.
        These lines exist for each box, but have ``set_visible(False)``
        when its box is not checked.

     *rectangles*
        List of :class:`matplotlib.patches.Rectangle` instances

    Connect to the CheckButtons with the :meth:`on_clicked` method
    """
    def __init__(self, ax, labels, actives):
        """
        Add check buttons to :class:`matplotlib.axes.Axes` instance *ax*

        *labels*
            A len(buttons) list of labels as strings

        *actives*
            A len(buttons) list of booleans indicating whether
             the button is active
        """
        AxesWidget.__init__(self, ax)

        ax.set_xticks([])
        ax.set_yticks([])
        ax.set_navigate(False)

        if len(labels) > 1:
            dy = 1. / (len(labels) + 1)
            ys = np.linspace(1 - dy, dy, len(labels))
        else:
            dy = 0.25
            ys = [0.5]

        cnt = 0
        axcolor = ax.get_axis_bgcolor()

        self.labels = []
        self.lines = []
        self.rectangles = []

        lineparams = {'color': 'k', 'linewidth': 1.25,
                      'transform': ax.transAxes, 'solid_capstyle': 'butt'}
        for y, label in zip(ys, labels):
            t = ax.text(0.25, y, label, transform=ax.transAxes,
                        horizontalalignment='left',
                        verticalalignment='center')

            w, h = dy / 2., dy / 2.
            x, y = 0.05, y - h / 2.

            p = Rectangle(xy=(x, y), width=w, height=h,
                          facecolor=axcolor,
                          transform=ax.transAxes)

            l1 = Line2D([x, x + w], [y + h, y], **lineparams)
            l2 = Line2D([x, x + w], [y, y + h], **lineparams)

            l1.set_visible(actives[cnt])
            l2.set_visible(actives[cnt])
            self.labels.append(t)
            self.rectangles.append(p)
            self.lines.append((l1, l2))
            ax.add_patch(p)
            ax.add_line(l1)
            ax.add_line(l2)
            cnt += 1

        self.connect_event('button_press_event', self._clicked)

        self.cnt = 0
        self.observers = {}

    def _clicked(self, event):
        if self.ignore(event):
            return
        if event.button != 1:
            return
        if event.inaxes != self.ax:
            return

        for p, t, lines in zip(self.rectangles, self.labels, self.lines):
            if (t.get_window_extent().contains(event.x, event.y) or
                    p.get_window_extent().contains(event.x, event.y)):
                l1, l2 = lines
                l1.set_visible(not l1.get_visible())
                l2.set_visible(not l2.get_visible())
                thist = t
                break
        else:
            return

        if self.drawon:
            self.ax.figure.canvas.draw()

        if not self.eventson:
            return
        for cid, func in self.observers.items():
            func(thist.get_text())

    def on_clicked(self, func):
        """
        When the button is clicked, call *func* with button label

        A connection id is returned which can be used to disconnect
        """
        cid = self.cnt
        self.observers[cid] = func
        self.cnt += 1
        return cid

    def disconnect(self, cid):
        """remove the observer with connection id *cid*"""
        try:
            del self.observers[cid]
        except KeyError:
            pass


class RadioButtons(AxesWidget):
    """
    A GUI neutral radio button

    The following attributes are exposed

     *ax*
        The :class:`matplotlib.axes.Axes` instance the buttons are in

     *activecolor*
        The color of the button when clicked

     *labels*
        A list of :class:`matplotlib.text.Text` instances

     *circles*
        A list of :class:`matplotlib.patches.Circle` instances

    Connect to the RadioButtons with the :meth:`on_clicked` method
    """
    def __init__(self, ax, labels, active=0, activecolor='blue'):
        """
        Add radio buttons to :class:`matplotlib.axes.Axes` instance *ax*

        *labels*
            A len(buttons) list of labels as strings

        *active*
            The index into labels for the button that is active

        *activecolor*
            The color of the button when clicked
        """
        AxesWidget.__init__(self, ax)

        self.activecolor = activecolor

        ax.set_xticks([])
        ax.set_yticks([])
        ax.set_navigate(False)
        dy = 1. / (len(labels) + 1)
        ys = np.linspace(1 - dy, dy, len(labels))
        cnt = 0
        axcolor = ax.get_axis_bgcolor()

        self.labels = []
        self.circles = []
        for y, label in zip(ys, labels):
            t = ax.text(0.25, y, label, transform=ax.transAxes,
                        horizontalalignment='left',
                        verticalalignment='center')

            if cnt == active:
                facecolor = activecolor
            else:
                facecolor = axcolor

            p = Circle(xy=(0.15, y), radius=0.05, facecolor=facecolor,
                       transform=ax.transAxes)

            self.labels.append(t)
            self.circles.append(p)
            ax.add_patch(p)
            cnt += 1

        self.connect_event('button_press_event', self._clicked)

        self.cnt = 0
        self.observers = {}

    def _clicked(self, event):
        if self.ignore(event):
            return
        if event.button != 1:
            return
        if event.inaxes != self.ax:
            return
        xy = self.ax.transAxes.inverted().transform_point((event.x, event.y))
        pclicked = np.array([xy[0], xy[1]])

        def inside(p):
            pcirc = np.array([p.center[0], p.center[1]])
            return dist(pclicked, pcirc) < p.radius

        for p, t in zip(self.circles, self.labels):
            if t.get_window_extent().contains(event.x, event.y) or inside(p):
                inp = p
                thist = t
                break
        else:
            return

        for p in self.circles:
            if p == inp:
                color = self.activecolor
            else:
                color = self.ax.get_axis_bgcolor()
            p.set_facecolor(color)

        if self.drawon:
            self.ax.figure.canvas.draw()

        if not self.eventson:
            return
        for cid, func in self.observers.items():
            func(thist.get_text())

    def on_clicked(self, func):
        """
        When the button is clicked, call *func* with button label

        A connection id is returned which can be used to disconnect
        """
        cid = self.cnt
        self.observers[cid] = func
        self.cnt += 1
        return cid

    def disconnect(self, cid):
        """remove the observer with connection id *cid*"""
        try:
            del self.observers[cid]
        except KeyError:
            pass


class SubplotTool(Widget):
    """
    A tool to adjust to subplot params of a :class:`matplotlib.figure.Figure`
    """
    def __init__(self, targetfig, toolfig):
        """
        *targetfig*
            The figure instance to adjust

        *toolfig*
            The figure instance to embed the subplot tool into. If
            None, a default figure will be created. If you are using
            this from the GUI
        """
        # FIXME: The docstring seems to just abruptly end without...

        self.targetfig = targetfig
        toolfig.subplots_adjust(left=0.2, right=0.9)

        class toolbarfmt:
            def __init__(self, slider):
                self.slider = slider

            def __call__(self, x, y):
                fmt = '%s=%s' % (self.slider.label.get_text(),
                                 self.slider.valfmt)
                return fmt % x

        self.axleft = toolfig.add_subplot(711)
        self.axleft.set_title('Click on slider to adjust subplot param')
        self.axleft.set_navigate(False)

        self.sliderleft = Slider(self.axleft, 'left',
                                 0, 1, targetfig.subplotpars.left,
                                 closedmax=False)
        self.sliderleft.on_changed(self.funcleft)

        self.axbottom = toolfig.add_subplot(712)
        self.axbottom.set_navigate(False)
        self.sliderbottom = Slider(self.axbottom,
                                   'bottom', 0, 1,
                                   targetfig.subplotpars.bottom,
                                   closedmax=False)
        self.sliderbottom.on_changed(self.funcbottom)

        self.axright = toolfig.add_subplot(713)
        self.axright.set_navigate(False)
        self.sliderright = Slider(self.axright, 'right', 0, 1,
                                  targetfig.subplotpars.right,
                                  closedmin=False)
        self.sliderright.on_changed(self.funcright)

        self.axtop = toolfig.add_subplot(714)
        self.axtop.set_navigate(False)
        self.slidertop = Slider(self.axtop, 'top', 0, 1,
                                targetfig.subplotpars.top,
                                closedmin=False)
        self.slidertop.on_changed(self.functop)

        self.axwspace = toolfig.add_subplot(715)
        self.axwspace.set_navigate(False)
        self.sliderwspace = Slider(self.axwspace, 'wspace',
                                   0, 1, targetfig.subplotpars.wspace,
                                   closedmax=False)
        self.sliderwspace.on_changed(self.funcwspace)

        self.axhspace = toolfig.add_subplot(716)
        self.axhspace.set_navigate(False)
        self.sliderhspace = Slider(self.axhspace, 'hspace',
                                   0, 1, targetfig.subplotpars.hspace,
                                   closedmax=False)
        self.sliderhspace.on_changed(self.funchspace)

        # constraints
        self.sliderleft.slidermax = self.sliderright
        self.sliderright.slidermin = self.sliderleft
        self.sliderbottom.slidermax = self.slidertop
        self.slidertop.slidermin = self.sliderbottom

        bax = toolfig.add_axes([0.8, 0.05, 0.15, 0.075])
        self.buttonreset = Button(bax, 'Reset')

        sliders = (self.sliderleft, self.sliderbottom, self.sliderright,
                   self.slidertop, self.sliderwspace, self.sliderhspace,)

        def func(event):
            thisdrawon = self.drawon

            self.drawon = False

            # store the drawon state of each slider
            bs = []
            for slider in sliders:
                bs.append(slider.drawon)
                slider.drawon = False

            # reset the slider to the initial position
            for slider in sliders:
                slider.reset()

            # reset drawon
            for slider, b in zip(sliders, bs):
                slider.drawon = b

            # draw the canvas
            self.drawon = thisdrawon
            if self.drawon:
                toolfig.canvas.draw()
                self.targetfig.canvas.draw()

        # during reset there can be a temporary invalid state
        # depending on the order of the reset so we turn off
        # validation for the resetting
        validate = toolfig.subplotpars.validate
        toolfig.subplotpars.validate = False
        self.buttonreset.on_clicked(func)
        toolfig.subplotpars.validate = validate

    def funcleft(self, val):
        self.targetfig.subplots_adjust(left=val)
        if self.drawon:
            self.targetfig.canvas.draw()

    def funcright(self, val):
        self.targetfig.subplots_adjust(right=val)
        if self.drawon:
            self.targetfig.canvas.draw()

    def funcbottom(self, val):
        self.targetfig.subplots_adjust(bottom=val)
        if self.drawon:
            self.targetfig.canvas.draw()

    def functop(self, val):
        self.targetfig.subplots_adjust(top=val)
        if self.drawon:
            self.targetfig.canvas.draw()

    def funcwspace(self, val):
        self.targetfig.subplots_adjust(wspace=val)
        if self.drawon:
            self.targetfig.canvas.draw()

    def funchspace(self, val):
        self.targetfig.subplots_adjust(hspace=val)
        if self.drawon:
            self.targetfig.canvas.draw()


class Cursor(AxesWidget):
    """
    A horizontal and vertical line span the axes that and move with
    the pointer.  You can turn off the hline or vline spectively with
    the attributes

      *horizOn*
        Controls the visibility of the horizontal line

      *vertOn*
        Controls the visibility of the horizontal line

    and the visibility of the cursor itself with the *visible* attribute
    """
    def __init__(self, ax, horizOn=True, vertOn=True, useblit=False,
                 **lineprops):
        """
        Add a cursor to *ax*.  If ``useblit=True``, use the backend-
        dependent blitting features for faster updates (GTKAgg
        only for now).  *lineprops* is a dictionary of line properties.

        .. plot :: mpl_examples/widgets/cursor.py
        """
        # TODO: Is the GTKAgg limitation still true?
        AxesWidget.__init__(self, ax)

        self.connect_event('motion_notify_event', self.onmove)
        self.connect_event('draw_event', self.clear)

        self.visible = True
        self.horizOn = horizOn
        self.vertOn = vertOn
        self.useblit = useblit and self.canvas.supports_blit

        if self.useblit:
            lineprops['animated'] = True
        self.lineh = ax.axhline(ax.get_ybound()[0], visible=False, **lineprops)
        self.linev = ax.axvline(ax.get_xbound()[0], visible=False, **lineprops)

        self.background = None
        self.needclear = False

    def clear(self, event):
        """clear the cursor"""
        if self.ignore(event):
            return
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)
        self.linev.set_visible(False)
        self.lineh.set_visible(False)

    def onmove(self, event):
        """on mouse motion draw the cursor if visible"""
        if self.ignore(event):
            return
        if not self.canvas.widgetlock.available(self):
            return
        if event.inaxes != self.ax:
            self.linev.set_visible(False)
            self.lineh.set_visible(False)

            if self.needclear:
                self.canvas.draw()
                self.needclear = False
            return
        self.needclear = True
        if not self.visible:
            return
        self.linev.set_xdata((event.xdata, event.xdata))

        self.lineh.set_ydata((event.ydata, event.ydata))
        self.linev.set_visible(self.visible and self.vertOn)
        self.lineh.set_visible(self.visible and self.horizOn)

        self._update()

    def _update(self):

        if self.useblit:
            if self.background is not None:
                self.canvas.restore_region(self.background)
            self.ax.draw_artist(self.linev)
            self.ax.draw_artist(self.lineh)
            self.canvas.blit(self.ax.bbox)
        else:

            self.canvas.draw_idle()

        return False


class MultiCursor(Widget):
    """
    Provide a vertical (default) and/or horizontal line cursor shared between
    multiple axes

    Example usage::

        from matplotlib.widgets import MultiCursor
        from pylab import figure, show, np

        t = np.arange(0.0, 2.0, 0.01)
        s1 = np.sin(2*np.pi*t)
        s2 = np.sin(4*np.pi*t)
        fig = figure()
        ax1 = fig.add_subplot(211)
        ax1.plot(t, s1)


        ax2 = fig.add_subplot(212, sharex=ax1)
        ax2.plot(t, s2)

        multi = MultiCursor(fig.canvas, (ax1, ax2), color='r', lw=1,
                            horizOn=False, vertOn=True)
        show()

    """
    def __init__(self, canvas, axes, useblit=True, horizOn=False, vertOn=True,
                 **lineprops):

        self.canvas = canvas
        self.axes = axes
        self.horizOn = horizOn
        self.vertOn = vertOn

        xmin, xmax = axes[-1].get_xlim()
        ymin, ymax = axes[-1].get_ylim()
        xmid = 0.5 * (xmin + xmax)
        ymid = 0.5 * (ymin + ymax)

        self.visible = True
        self.useblit = useblit and self.canvas.supports_blit
        self.background = None
        self.needclear = False

        if useblit:
            lineprops['animated'] = True

        if vertOn:
            self.vlines = [ax.axvline(xmid, visible=False, **lineprops)
                           for ax in axes]
        else:
            self.vlines = []

        if horizOn:
            self.hlines = [ax.axhline(ymid, visible=False, **lineprops)
                           for ax in axes]
        else:
            self.hlines = []

        self.canvas.mpl_connect('motion_notify_event', self.onmove)
        self.canvas.mpl_connect('draw_event', self.clear)

    def clear(self, event):
        """clear the cursor"""
        if self.useblit:
            self.background = (
                self.canvas.copy_from_bbox(self.canvas.figure.bbox))
        for line in self.vlines + self.hlines:
            line.set_visible(False)

    def onmove(self, event):
        if event.inaxes is None:
            return
        if not self.canvas.widgetlock.available(self):
            return
        self.needclear = True
        if not self.visible:
            return
        if self.vertOn:
            for line in self.vlines:
                line.set_xdata((event.xdata, event.xdata))
                line.set_visible(self.visible)
        if self.horizOn:
            for line in self.hlines:
                line.set_ydata((event.ydata, event.ydata))
                line.set_visible(self.visible)
        self._update()

    def _update(self):
        if self.useblit:
            if self.background is not None:
                self.canvas.restore_region(self.background)
            if self.vertOn:
                for ax, line in zip(self.axes, self.vlines):
                    ax.draw_artist(line)
            if self.horizOn:
                for ax, line in zip(self.axes, self.hlines):
                    ax.draw_artist(line)
            self.canvas.blit(self.canvas.figure.bbox)
        else:

            self.canvas.draw_idle()


class SpanSelector(AxesWidget):
    """
    Select a min/max range of the x or y axes for a matplotlib Axes

    Example usage::

        ax = subplot(111)
        ax.plot(x,y)

        def onselect(vmin, vmax):
            print vmin, vmax
        span = SpanSelector(ax, onselect, 'horizontal')

    *onmove_callback* is an optional callback that is called on mouse
      move within the span range

    """

    def __init__(self, ax, onselect, direction, minspan=None, useblit=False,
                 rectprops=None, onmove_callback=None):
        """
        Create a span selector in *ax*.  When a selection is made, clear
        the span and call *onselect* with::

            onselect(vmin, vmax)

        and clear the span.

        *direction* must be 'horizontal' or 'vertical'

        If *minspan* is not *None*, ignore events smaller than *minspan*

        The span rectangle is drawn with *rectprops*; default::
          rectprops = dict(facecolor='red', alpha=0.5)

        Set the visible attribute to *False* if you want to turn off
        the functionality of the span selector
        """
        AxesWidget.__init__(self, ax)

        if rectprops is None:
            rectprops = dict(facecolor='red', alpha=0.5)

        assert direction in ['horizontal', 'vertical'], 'Must choose horizontal or vertical for direction'
        self.direction = direction

        self.visible = True

        self.rect = None
        self.background = None
        self.pressv = None

        self.rectprops = rectprops
        self.onselect = onselect
        self.onmove_callback = onmove_callback
        self.minspan = minspan

        # Needed when dragging out of axes
        self.buttonDown = False
        self.prev = (0, 0)

        # Set useblit based on original canvas.
        self.useblit = useblit and self.canvas.supports_blit

        # Reset canvas so that `new_axes` connects events.
        self.canvas = None
        self.new_axes(ax)

    def new_axes(self, ax):
        self.ax = ax
        if self.canvas is not ax.figure.canvas:
            self.disconnect_events()

            self.canvas = ax.figure.canvas
            self.connect_event('motion_notify_event', self.onmove)
            self.connect_event('button_press_event', self.press)
            self.connect_event('button_release_event', self.release)
            self.connect_event('draw_event', self.update_background)

        if self.direction == 'horizontal':
            trans = blended_transform_factory(self.ax.transData,
                                              self.ax.transAxes)
            w, h = 0, 1
        else:
            trans = blended_transform_factory(self.ax.transAxes,
                                              self.ax.transData)
            w, h = 1, 0
        self.rect = Rectangle((0, 0), w, h,
                              transform=trans,
                              visible=False,
                              **self.rectprops)

        if not self.useblit:
            self.ax.add_patch(self.rect)

    def update_background(self, event):
        """force an update of the background"""
        # If you add a call to `ignore` here, you'll want to check edge case:
        # `release` can call a draw event even when `ignore` is True.
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)

    def ignore(self, event):
        """return *True* if *event* should be ignored"""
        widget_off = not self.visible or not self.active
        non_event = event.inaxes != self.ax or event.button != 1
        return widget_off or non_event

    def press(self, event):
        """on button press event"""
        if self.ignore(event):
            return
        self.buttonDown = True

        self.rect.set_visible(self.visible)
        if self.direction == 'horizontal':
            self.pressv = event.xdata
        else:
            self.pressv = event.ydata
        return False

    def release(self, event):
        """on button release event"""
        if self.ignore(event) and not self.buttonDown:
            return
        if self.pressv is None:
            return
        self.buttonDown = False

        self.rect.set_visible(False)
        self.canvas.draw()
        vmin = self.pressv
        if self.direction == 'horizontal':
            vmax = event.xdata or self.prev[0]
        else:
            vmax = event.ydata or self.prev[1]

        if vmin > vmax:
            vmin, vmax = vmax, vmin
        span = vmax - vmin
        if self.minspan is not None and span < self.minspan:
            return
        self.onselect(vmin, vmax)
        self.pressv = None
        return False

    def update(self):
        """
        Draw using newfangled blit or oldfangled draw depending
        on *useblit*
        """
        if self.useblit:
            if self.background is not None:
                self.canvas.restore_region(self.background)
            self.ax.draw_artist(self.rect)
            self.canvas.blit(self.ax.bbox)
        else:
            self.canvas.draw_idle()

        return False

    def onmove(self, event):
        """on motion notify event"""
        if self.pressv is None or self.ignore(event):
            return
        x, y = event.xdata, event.ydata
        self.prev = x, y
        if self.direction == 'horizontal':
            v = x
        else:
            v = y

        minv, maxv = v, self.pressv
        if minv > maxv:
            minv, maxv = maxv, minv
        if self.direction == 'horizontal':
            self.rect.set_x(minv)
            self.rect.set_width(maxv - minv)
        else:
            self.rect.set_y(minv)
            self.rect.set_height(maxv - minv)

        if self.onmove_callback is not None:
            vmin = self.pressv
            if self.direction == 'horizontal':
                vmax = event.xdata or self.prev[0]
            else:
                vmax = event.ydata or self.prev[1]

            if vmin > vmax:
                vmin, vmax = vmax, vmin
            self.onmove_callback(vmin, vmax)

        self.update()
        return False


class RectangleSelector(AxesWidget):
    """
    Select a min/max range of the x axes for a matplotlib Axes

    Example usage::

        from matplotlib.widgets import  RectangleSelector
        from pylab import *

        def onselect(eclick, erelease):
          'eclick and erelease are matplotlib events at press and release'
          print ' startposition : (%f, %f)' % (eclick.xdata, eclick.ydata)
          print ' endposition   : (%f, %f)' % (erelease.xdata, erelease.ydata)
          print ' used button   : ', eclick.button

        def toggle_selector(event):
            print ' Key pressed.'
            if event.key in ['Q', 'q'] and toggle_selector.RS.active:
                print ' RectangleSelector deactivated.'
                toggle_selector.RS.set_active(False)
            if event.key in ['A', 'a'] and not toggle_selector.RS.active:
                print ' RectangleSelector activated.'
                toggle_selector.RS.set_active(True)

        x = arange(100)/(99.0)
        y = sin(x)
        fig = figure
        ax = subplot(111)
        ax.plot(x,y)

        toggle_selector.RS = RectangleSelector(ax, onselect, drawtype='line')
        connect('key_press_event', toggle_selector)
        show()
    """
    def __init__(self, ax, onselect, drawtype='box',
                 minspanx=None, minspany=None, useblit=False,
                 lineprops=None, rectprops=None, spancoords='data',
                 button=None):

        """
        Create a selector in *ax*.  When a selection is made, clear
        the span and call onselect with::

          onselect(pos_1, pos_2)

        and clear the drawn box/line. The ``pos_1`` and ``pos_2`` are
        arrays of length 2 containing the x- and y-coordinate.

        If *minspanx* is not *None* then events smaller than *minspanx*
        in x direction are ignored (it's the same for y).

        The rectangle is drawn with *rectprops*; default::

          rectprops = dict(facecolor='red', edgecolor = 'black',
                           alpha=0.5, fill=False)

        The line is drawn with *lineprops*; default::

          lineprops = dict(color='black', linestyle='-',
                           linewidth = 2, alpha=0.5)

        Use *drawtype* if you want the mouse to draw a line,
        a box or nothing between click and actual position by setting

        ``drawtype = 'line'``, ``drawtype='box'`` or ``drawtype = 'none'``.

        *spancoords* is one of 'data' or 'pixels'.  If 'data', *minspanx*
        and *minspanx* will be interpreted in the same coordinates as
        the x and y axis. If 'pixels', they are in pixels.

        *button* is a list of integers indicating which mouse buttons should
        be used for rectangle selection.  You can also specify a single
        integer if only a single button is desired.  Default is *None*,
        which does not limit which button can be used.

        Note, typically:
         1 = left mouse button
         2 = center mouse button (scroll wheel)
         3 = right mouse button
        """
        AxesWidget.__init__(self, ax)

        self.visible = True
        self.connect_event('motion_notify_event', self.onmove)
        self.connect_event('button_press_event', self.press)
        self.connect_event('button_release_event', self.release)
        self.connect_event('draw_event', self.update_background)

        self.active = True                    # for activation / deactivation
        self.to_draw = None
        self.background = None

        if drawtype == 'none':
            drawtype = 'line'                        # draw a line but make it
            self.visible = False                     # invisible

        if drawtype == 'box':
            if rectprops is None:
                rectprops = dict(facecolor='white', edgecolor='black',
                                 alpha=0.5, fill=False)
            self.rectprops = rectprops
            self.to_draw = Rectangle((0, 0),
                                     0, 1, visible=False, **self.rectprops)
            self.ax.add_patch(self.to_draw)
        if drawtype == 'line':
            if lineprops is None:
                lineprops = dict(color='black', linestyle='-',
                                 linewidth=2, alpha=0.5)
            self.lineprops = lineprops
            self.to_draw = Line2D([0, 0], [0, 0], visible=False,
                                  **self.lineprops)
            self.ax.add_line(self.to_draw)

        self.onselect = onselect
        self.useblit = useblit and self.canvas.supports_blit
        self.minspanx = minspanx
        self.minspany = minspany

        if button is None or isinstance(button, list):
            self.validButtons = button
        elif isinstance(button, int):
            self.validButtons = [button]

        assert(spancoords in ('data', 'pixels'))

        self.spancoords = spancoords
        self.drawtype = drawtype
        # will save the data (position at mouseclick)
        self.eventpress = None
        # will save the data (pos. at mouserelease)
        self.eventrelease = None

    def update_background(self, event):
        """force an update of the background"""
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)

    def ignore(self, event):
        """return *True* if *event* should be ignored"""
        if not self.active:
            return True

        # If canvas was locked
        if not self.canvas.widgetlock.available(self):
            return True

        # Only do rectangle selection if event was triggered
        # with a desired button
        if self.validButtons is not None:
            if not event.button in self.validButtons:
                return True

        # If no button was pressed yet ignore the event if it was out
        # of the axes
        if self.eventpress is None:
            return event.inaxes != self.ax

        # If a button was pressed, check if the release-button is the
        # same. If event is out of axis, limit the data coordinates to axes
        # boundaries.
        if event.button == self.eventpress.button and event.inaxes != self.ax:
            (xdata, ydata) = self.ax.transData.inverted().transform_point(
                (event.x, event.y))
            x0, x1 = self.ax.get_xbound()
            y0, y1 = self.ax.get_ybound()
            xdata = max(x0, xdata)
            xdata = min(x1, xdata)
            ydata = max(y0, ydata)
            ydata = min(y1, ydata)
            event.xdata = xdata
            event.ydata = ydata
            return False

        # If a button was pressed, check if the release-button is the
        # same.
        return (event.inaxes != self.ax or
                event.button != self.eventpress.button)

    def press(self, event):
        """on button press event"""
        if self.ignore(event):
            return
        # make the drawed box/line visible get the click-coordinates,
        # button, ...
        self.to_draw.set_visible(self.visible)
        self.eventpress = event
        return False

    def release(self, event):
        """on button release event"""
        if self.eventpress is None or self.ignore(event):
            return
        # make the box/line invisible again
        self.to_draw.set_visible(False)
        self.canvas.draw()
        # release coordinates, button, ...
        self.eventrelease = event

        if self.spancoords == 'data':
            xmin, ymin = self.eventpress.xdata, self.eventpress.ydata
            xmax, ymax = self.eventrelease.xdata, self.eventrelease.ydata
            # calculate dimensions of box or line get values in the right
            # order
        elif self.spancoords == 'pixels':
            xmin, ymin = self.eventpress.x, self.eventpress.y
            xmax, ymax = self.eventrelease.x, self.eventrelease.y
        else:
            raise ValueError('spancoords must be "data" or "pixels"')

        if xmin > xmax:
            xmin, xmax = xmax, xmin
        if ymin > ymax:
            ymin, ymax = ymax, ymin

        spanx = xmax - xmin
        spany = ymax - ymin
        xproblems = self.minspanx is not None and spanx < self.minspanx
        yproblems = self.minspany is not None and spany < self.minspany

        if (((self.drawtype == 'box') or (self.drawtype == 'line')) and
                (xproblems or yproblems)):
            # check if drawn distance (if it exists) is not too small in
            # neither x nor y-direction
            return

        self.onselect(self.eventpress, self.eventrelease)
                                              # call desired function
        self.eventpress = None                # reset the variables to their
        self.eventrelease = None              # inital values
        return False

    def update(self):
        """draw using newfangled blit or oldfangled draw depending on
        useblit

        """
        if self.useblit:
            if self.background is not None:
                self.canvas.restore_region(self.background)
            self.ax.draw_artist(self.to_draw)
            self.canvas.blit(self.ax.bbox)
        else:
            self.canvas.draw_idle()
        return False

    def onmove(self, event):
        """on motion notify event if box/line is wanted"""
        if self.eventpress is None or self.ignore(event):
            return
        x, y = event.xdata, event.ydata             # actual position (with
                                                   #   (button still pressed)
        if self.drawtype == 'box':
            minx, maxx = self.eventpress.xdata, x  # click-x and actual mouse-x
            miny, maxy = self.eventpress.ydata, y  # click-y and actual mouse-y
            if minx > maxx:
                minx, maxx = maxx, minx  # get them in the right order
            if miny > maxy:
                miny, maxy = maxy, miny
            self.to_draw.set_x(minx)             # set lower left of box
            self.to_draw.set_y(miny)
            self.to_draw.set_width(maxx - minx)  # set width and height of box
            self.to_draw.set_height(maxy - miny)
            self.update()
            return False
        if self.drawtype == 'line':
            self.to_draw.set_data([self.eventpress.xdata, x],
                                  [self.eventpress.ydata, y])
            self.update()
            return False

    def set_active(self, active):
        """
        Use this to activate / deactivate the RectangleSelector
        from your program with an boolean parameter *active*.
        """
        self.active = active

    def get_active(self):
        """ Get status of active mode (boolean variable)"""
        return self.active


class LassoSelector(AxesWidget):
    """Selection curve of an arbitrary shape.

    The selected path can be used in conjunction with
    :func:`~matplotlib.path.Path.contains_point` to select
    data points from an image.

    In contrast to :class:`Lasso`, `LassoSelector` is written with an interface
    similar to :class:`RectangleSelector` and :class:`SpanSelector` and will
    continue to interact with the axes until disconnected.

    Parameters:

    *ax* : :class:`~matplotlib.axes.Axes`
        The parent axes for the widget.
    *onselect* : function
        Whenever the lasso is released, the `onselect` function is called and
        passed the vertices of the selected path.

    Example usage::

        ax = subplot(111)
        ax.plot(x,y)

        def onselect(verts):
            print verts
        lasso = LassoSelector(ax, onselect)

    """

    def __init__(self, ax, onselect=None, useblit=True, lineprops=None):
        AxesWidget.__init__(self, ax)

        self.useblit = useblit and self.canvas.supports_blit
        self.onselect = onselect
        self.verts = None

        if lineprops is None:
            lineprops = dict()
        self.line = Line2D([], [], **lineprops)
        self.line.set_visible(False)
        self.ax.add_line(self.line)

        self.connect_event('button_press_event', self.onpress)
        self.connect_event('button_release_event', self.onrelease)
        self.connect_event('motion_notify_event', self.onmove)
        self.connect_event('draw_event', self.update_background)

    def ignore(self, event):
        wrong_button = hasattr(event, 'button') and event.button != 1
        return not self.active or wrong_button

    def onpress(self, event):
        if self.ignore(event) or event.inaxes != self.ax:
            return
        self.verts = [(event.xdata, event.ydata)]
        self.line.set_visible(True)

    def onrelease(self, event):
        if self.ignore(event):
            return
        if self.verts is not None:
            if event.inaxes == self.ax:
                self.verts.append((event.xdata, event.ydata))
            self.onselect(self.verts)
        self.line.set_data([[], []])
        self.line.set_visible(False)
        self.verts = None

    def onmove(self, event):
        if self.ignore(event) or event.inaxes != self.ax:
            return
        if self.verts is None:
            return
        if event.inaxes != self.ax:
            return
        if event.button != 1:
            return
        self.verts.append((event.xdata, event.ydata))

        self.line.set_data(list(zip(*self.verts)))

        if self.useblit:
            self.canvas.restore_region(self.background)
            self.ax.draw_artist(self.line)
            self.canvas.blit(self.ax.bbox)
        else:
            self.canvas.draw_idle()

    def update_background(self, event):
        if self.ignore(event):
            return
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)


class Lasso(AxesWidget):
    """Selection curve of an arbitrary shape.

    The selected path can be used in conjunction with
    :func:`~matplotlib.path.Path.contains_point` to select data points
    from an image.

    Unlike :class:`LassoSelector`, this must be initialized with a starting
    point `xy`, and the `Lasso` events are destroyed upon release.

    Parameters:

    *ax* : :class:`~matplotlib.axes.Axes`
        The parent axes for the widget.
    *xy* : array
        Coordinates of the start of the lasso.
    *callback* : function
        Whenever the lasso is released, the `callback` function is called and
        passed the vertices of the selected path.

    """

    def __init__(self, ax, xy, callback=None, useblit=True):
        AxesWidget.__init__(self, ax)

        self.useblit = useblit and self.canvas.supports_blit
        if self.useblit:
            self.background = self.canvas.copy_from_bbox(self.ax.bbox)

        x, y = xy
        self.verts = [(x, y)]
        self.line = Line2D([x], [y], linestyle='-', color='black', lw=2)
        self.ax.add_line(self.line)
        self.callback = callback
        self.connect_event('button_release_event', self.onrelease)
        self.connect_event('motion_notify_event', self.onmove)

    def onrelease(self, event):
        if self.ignore(event):
            return
        if self.verts is not None:
            self.verts.append((event.xdata, event.ydata))
            if len(self.verts) > 2:
                self.callback(self.verts)
            self.ax.lines.remove(self.line)
        self.verts = None
        self.disconnect_events()

    def onmove(self, event):
        if self.ignore(event):
            return
        if self.verts is None:
            return
        if event.inaxes != self.ax:
            return
        if event.button != 1:
            return
        self.verts.append((event.xdata, event.ydata))

        self.line.set_data(list(zip(*self.verts)))

        if self.useblit:
            self.canvas.restore_region(self.background)
            self.ax.draw_artist(self.line)
            self.canvas.blit(self.ax.bbox)
        else:
            self.canvas.draw_idle()
