Source code for enable.primitives.annotater

# (C) Copyright 2005-2022 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
#
# Thanks for using Enthought open source!
"""
Define an Annotater component that allows a user to annotate an underlying
component
"""

from traits.api import Event, PrefixList
from traitsui.api import Group, View

from enable.api import Component
from enable.colors import ColorTrait


class Annotater(Component):

    color = ColorTrait((0.0, 0.0, 0.0, 0.2))
    style = PrefixList(["rectangular", "freehand"],
                       default_value="rectangular")
    annotation = Event

    traits_view = View(
        Group("<component>", id="component"),
        Group("<links>", id="links"),
        Group("color", "style", id="annotater", style="custom"),
    )

    # -------------------------------------------------------------------------
    # Mouse event handlers
    # -------------------------------------------------------------------------

    def _left_down_changed(self, event):
        event.handled = True
        self.window.mouse_owner = self
        self._cur_x, self._cur_y = event.x, event.y
        self._start_x, self._start_y = event.x, event.y

    def _left_up_changed(self, event):
        event.handled = True
        self.window.mouse_owner = None
        if self.xy_in_bounds(event):
            self.annotation = (
                min(self._start_x, event.x),
                min(self._start_y, event.y),
                abs(self._start_x - event.x),
                abs(self._start_y - event.y),
            )
        self._start_x = self._start_y = self._cur_x = self._cur_y = None
        self.redraw()

    def _mouse_move_changed(self, event):
        event.handled = True
        if self._start_x is not None:
            x = max(min(event.x, self.right - 1.0), self.x)
            y = max(min(event.y, self.top - 1.0), self.y)
            if (x != self._cur_x) or (y != self._cur_y):
                self._cur_x, self._cur_y = x, y
                self.redraw()

    # -------------------------------------------------------------------------
    # "Component" interface
    # -------------------------------------------------------------------------

    def _draw(self, gc):
        "Draw the contents of the control"
        if self._start_x is not None:
            with gc:
                gc.set_fill_color(self.color_)
                gc.begin_path()
                gc.rect(
                    min(self._start_x, self._cur_x),
                    min(self._start_y, self._cur_y),
                    abs(self._start_x - self._cur_x),
                    abs(self._start_y - self._cur_y),
                )
                gc.fill_path()
        return