# -*- coding: utf-8 -*-
"""
This module contains the class which inherits from QtWidgets.QGraphicsView in order to add some custom functionality
to a graphics view. Particularly, navigation controls for navigating the viewport.
"""

from artv2.third_party.Qt import QtWidgets, QtGui, QtCore


class ARTv2GraphicsView(QtWidgets.QGraphicsView):

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    def __init__(self, scene, parent=None):

        super(ARTv2GraphicsView, self).__init__(parent)

        self.scene = scene
        self._init_interface()

        self.setScene(self.scene)
        self.zoom_in_factor = 1.25
        self.current_zoom = 10
        self.zoom_step = 1

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    def _init_interface(self):
        """
        Set some flags for the graphics view.
        """

        self.setRenderHints(QtGui.QPainter.Antialiasing | QtGui.QPainter.HighQualityAntialiasing |
                           QtGui.QPainter.TextAntialiasing | QtGui.QPainter.SmoothPixmapTransform)

        self.setViewportUpdateMode(QtWidgets.QGraphicsView.FullViewportUpdate)
        self.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
        self.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)

        self.setTransformationAnchor(QtWidgets.QGraphicsView.AnchorUnderMouse)

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    def mousePressEvent(self, event):
        """
        Override mouse press event for dragging around viewport with the MMB
        :param event:
        :return:
        """

        if event.button() == QtCore.Qt.MiddleButton:
            self._middle_mouse_button_press(event)
        elif event.button() == QtCore.Qt.LeftButton:
            self._left_mouse_button_press(event)
        elif event.button() == QtCore.Qt.RightButton:
            self._right_mouse_button_press(event)
        else:
            super(ARTv2GraphicsView, self).mousePressEvent(event)

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    def mouseReleaseEvent(self, event):
        """
        Override mouse press event for dragging around viewport with the MMB
        :param event:
        :return:
        """

        if event.button() == QtCore.Qt.MiddleButton:
            self._middle_mouse_button_release(event)
        elif event.button() == QtCore.Qt.LeftButton:
            self._left_mouse_button_release(event)
        elif event.button() == QtCore.Qt.RightButton:
            self._right_mouse_button_release(event)

        else:
            super(ARTv2GraphicsView, self).mouseReleaseEvent(event)

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    def wheelEvent(self, event):
        """
        OVerride mouse scroll event for zooming in and out.
        :param event:
        :return:
        """

        zoom_out_factor = 1 / self.zoom_in_factor

        # if you are scrolling in (up) on the MMB
        if event.angleDelta().y() > 0:
            zoom_factor = self.zoom_in_factor
            self.current_zoom += self.zoom_step

        else:
            zoom_factor = zoom_out_factor
            self.current_zoom -= self.zoom_step

        self.scale(zoom_factor, zoom_factor)

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    def _middle_mouse_button_press(self, event):
        """
        By default, setting drag mode wanted to use the LMB, so this will take in a MMB event, and make the MMB do
        the same thing as the LMB
        :param event:
        :return:
        """
        release_event = QtGui.QMouseEvent(QtCore.QEvent.MouseButtonRelease, event.localPos(),
                                           event.screenPos(), QtCore.Qt.LeftButton, QtCore.Qt.NoButton,
                                           event.modifiers())
        super(ARTv2GraphicsView, self).mouseReleaseEvent(release_event)
        self.setDragMode(QtWidgets.QGraphicsView.ScrollHandDrag)

        fake_event = QtGui.QMouseEvent(event.type(), event.localPos(), event.screenPos(), QtCore.Qt.LeftButton,
                                       event.buttons() | QtCore.Qt.LeftButton, event.modifiers())
        super(ARTv2GraphicsView, self).mousePressEvent(fake_event)

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    def _left_mouse_button_press(self, event):

        return super(ARTv2GraphicsView, self).mousePressEvent(event)

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    def _right_mouse_button_press(self, event):

        return super(ARTv2GraphicsView, self).mousePressEvent(event)

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    def _middle_mouse_button_release(self, event):

        fake_event = QtGui.QMouseEvent(event.type(), event.localPos(), event.screenPos(), QtCore.Qt.LeftButton,
                                       event.buttons() | QtCore.Qt.LeftButton, event.modifiers())

        super(ARTv2GraphicsView, self).mouseReleaseEvent(fake_event)
        self.setDragMode(QtWidgets.QGraphicsView.NoDrag)

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    def _left_mouse_button_release(self, event):

        return super(ARTv2GraphicsView, self).mouseReleaseEvent(event)

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    def _right_mouse_button_release(self, event):

        return super(ARTv2GraphicsView, self).mouseReleaseEvent(event)