Source code for sas.qtgui.Plotting.Slicers.Arc

"""
    Arc slicer for 2D data
"""
import numpy as np

from sas.qtgui.Plotting.Slicers.BaseInteractor import BaseInteractor

class ArcInteractor(BaseInteractor):
    """
    Select an annulus through a 2D plot
    """
    def __init__(self, base, axes, color='black', zorder=5, r=1.0,
                 theta1=np.pi / 8, theta2=np.pi / 4):
        BaseInteractor.__init__(self, base, axes, color=color)
        self.markers = []
        self.axes = axes
        self._mouse_x = r
        self._mouse_y = 0
        self._save_x = r
        self._save_y = 0
        self.scale = 10.0
        self.theta1 = theta1
        self.theta2 = theta2
        self.radius = r
        [self.arc] = self.axes.plot([], [], linestyle='-', marker='', color=self.color)
        self.npts = 20
        self.has_move = False
        self.connect_markers([self.arc])
        self.update()

    def set_layer(self, n):
        """
        Allow adding plot to the same panel
        :param n: the number of layer
        """
        self.layernum = n
        self.update()

    def clear(self):
        """
        Clear this slicer and its markers
        """
        self.clear_markers()
        try:
            for item in self.markers:
                item.remove()
            self.arc.remove()
        except:
            # Old version of matplotlib
            for item in range(len(self.axes.lines)):
                del self.axes.lines[0]

    def get_radius(self):
        """
        Return arc radius
        """
        radius = np.sqrt(np.power(self._mouse_x, 2) + \
                           np.power(self._mouse_y, 2))
        return radius

    def update(self, theta1=None, theta2=None, nbins=None, r=None):
        """
        Update the plotted arc
        :param theta1: starting angle of the arc
        :param theta2: ending angle of the arc
        :param nbins: number of points along the arc
        :param r: radius of the arc
        """
        # Plot inner circle
        x = []
        y = []
        if theta1 is not None:
            self.theta1 = theta1
        if theta2 is not None:
            self.theta2 = theta2
        while self.theta2 < self.theta1:
            self.theta2 += (2 * np.pi)
        while self.theta2 >= (self.theta1 + 2 * np.pi):
            self.theta2 -= (2 * np.pi)
        self.npts = int((self.theta2 - self.theta1) / (np.pi / 120))

        if r is None:
            self.radius = np.sqrt(np.power(self._mouse_x, 2) + \
                                     np.power(self._mouse_y, 2))
        else:
            self.radius = r
        for i in range(self.npts):
            phi = (self.theta2 - self.theta1) / (self.npts - 1) * i + self.theta1
            xval = 1.0 * self.radius * np.cos(phi)
            yval = 1.0 * self.radius * np.sin(phi)

            x.append(xval)
            y.append(yval)
        self.arc.set_data(x, y)

    def save(self, ev):
        """
        Remember the roughness for this layer and the next so that we
        can restore on Esc.
        """
        self._save_x = self._mouse_x
        self._save_y = self._mouse_y
        self.base.freeze_axes()

    def moveend(self, ev):
        """
        After a dragging motion reset the flag self.has_move to False
        :param ev: event
        """
        self.has_move = False

        self.base.moveend(ev)

    def restore(self):
        """
        Restore the roughness for this layer.
        """
        self._mouse_x = self._save_x
        self._mouse_y = self._save_y

    def move(self, x, y, ev):
        """
        Process move to a new position, making sure that the move is allowed.
        """
        self._mouse_x = x
        self._mouse_y = y
        self.has_move = True
        self.base.base.update()

    def set_cursor(self, radius, phi_min, phi_max, nbins):
        """
        """
        self.theta1 = phi_min
        self.theta2 = phi_max
        self.update(nbins=nbins, r=radius)

    def get_params(self):
        """
        """
        params = {}
        params["radius"] = self.radius
        params["theta1"] = self.theta1
        params["theta2"] = self.theta2
        return params

    def set_params(self, params):
        """
        """
        x = params["radius"]
        phi_max = self.theta2
        nbins = self.npts
        self.set_cursor(x, self._mouse_y, phi_max, nbins)