# (C) Copyright 2005-2021 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
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# Thanks for using Enthought open source!

""" Defines the LassoOverlay class.
"""


from numpy import concatenate, newaxis

# Enthought library imports
from enable.api import ColorTrait, LineStyle
from traits.api import Float, Instance, Bool

# Local imports
from chaco.abstract_overlay import AbstractOverlay


class LassoOverlay(AbstractOverlay):
    """Draws a lasso selection region on top of a plot.

    LassoOverlay gets its data from a LassoSelection.
    """

    #: The LassoSelection that provides the data for this overlay.
    lasso_selection = Instance("chaco.tools.lasso_selection.LassoSelection")
    #: The fill color for the selection region.
    selection_fill_color = ColorTrait("lightskyblue")
    #: The border color for the selection region.
    selection_border_color = ColorTrait("dodgerblue")
    #: The transparency level for the selection fill color.
    selection_alpha = Float(0.8)
    #: The width of the selection border.
    selection_border_width = Float(2.0)
    #: The line style of the selection border.
    selection_border_dash = LineStyle

    #: The background color (overrides AbstractOverlay).
    bgcolor = "clear"

    # Whether to draw the lasso
    # depends on the state of the lasso tool
    _draw_selection = Bool(False)

    def overlay(self, other_component, gc, view_bounds=None, mode="normal"):
        """Draws this component overlaid on another component.

        Implements AbstractOverlay.
        """
        if not self._draw_selection:
            return
        with gc:
            c = other_component
            gc.clip_to_rect(c.x, c.y, c.width, c.height)
            with gc:
                # We may need to make map_screen more flexible in the number of
                # dimensions it accepts for ths to work well.
                for selection in self.lasso_selection.disjoint_selections:
                    points = self.component.map_screen(selection)
                    if len(points) == 0:
                        return
                    points = concatenate((points, points[0, newaxis]), axis=0)
                    gc.set_line_width(self.selection_border_width)
                    gc.set_line_dash(self.selection_border_dash_)
                    gc.set_fill_color(self.selection_fill_color_)
                    gc.set_stroke_color(self.selection_border_color_)
                    gc.set_alpha(self.selection_alpha)
                    gc.lines(points)
                    gc.draw_path()

    def _updated_changed_for_lasso_selection(self):
        self.component.invalidate_draw()
        self.component.request_redraw()

    def _event_state_fired_for_lasso_selection(self, val):
        self._draw_selection = val == "selecting"
        self.component.invalidate_draw()
        self.component.request_redraw()