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# Source code for pyqtgraph.widgets.GraphicsView

    """
    GraphicsView.py -   Extension of QGraphicsView
    Copyright 2010  Luke Campagnola
    Distributed under MIT/X11 license. See license.txt for more information.
    """

    from .. import functions as fn
    from .. import getConfigOption
    from ..GraphicsScene import GraphicsScene
    from ..Point import Point
    from ..Qt import QtCore, QtGui, QtWidgets
    from ..Qt import OpenGLHelpers

    __all__ = ['GraphicsView']

    class GraphicsView(QtWidgets.QGraphicsView):
        """Re-implementation of QGraphicsView that removes scrollbars and allows unambiguous control of the
        viewed coordinate range. Also automatically creates a GraphicsScene and a central QGraphicsWidget
        that is automatically scaled to the full view geometry.

        This widget is the basis for :class:`PlotWidget <pyqtgraph.PlotWidget>`,
        :class:`GraphicsLayoutWidget <pyqtgraph.GraphicsLayoutWidget>`, and the view widget in
        :class:`ImageView <pyqtgraph.ImageView>`.

        By default, the view coordinate system matches the widget's pixel coordinates and
        automatically updates when the view is resized. This can be overridden by setting
        autoPixelRange=False. The exact visible range can be set with setRange().

        The view can be panned using the middle mouse button and scaled using the right mouse button if
        enabled via enableMouse()  (but ordinarily, we use ViewBox for this functionality)."""

        sigDeviceRangeChanged = QtCore.Signal(object, object)
        sigDeviceTransformChanged = QtCore.Signal(object)
        sigMouseReleased = QtCore.Signal(object)
        sigSceneMouseMoved = QtCore.Signal(object)
        #sigRegionChanged = QtCore.Signal(object)
        sigScaleChanged = QtCore.Signal(object)
        lastFileDir = None

        def __init__(self, parent=None, useOpenGL=None, background='default'):
            """
            ==============  ============================================================
            **Arguments:**
            parent          Optional parent widget
            useOpenGL       If True, the GraphicsView will use OpenGL to do all of its
                            rendering. This can improve performance on some systems,
                            but may also introduce bugs (the combination of
                            QGraphicsView and QOpenGLWidget is still an 'experimental'
                            feature of Qt)
            background      Set the background color of the GraphicsView. Accepts any
                            single argument accepted by
                            :func:`mkColor <pyqtgraph.mkColor>`. By
                            default, the background color is determined using the
                            'backgroundColor' configuration option (see
                            :func:`setConfigOptions <pyqtgraph.setConfigOptions>`).
            ==============  ============================================================
            """

            self.closed = False

            QtWidgets.QGraphicsView.__init__(self, parent)

            # This connects a cleanup function to QApplication.aboutToQuit. It is
            # called from here because we have no good way to react when the
            # QApplication is created by the user.
            # See pyqtgraph.__init__.py
            from .. import _connectCleanup
            _connectCleanup()

            if useOpenGL is None:
                useOpenGL = getConfigOption('useOpenGL')

            self.useOpenGL(useOpenGL)
            self.setCacheMode(self.CacheModeFlag.CacheBackground)

            ## This might help, but it's probably dangerous in the general case..
            #self.setOptimizationFlag(self.DontSavePainterState, True)

            self.setBackgroundRole(QtGui.QPalette.ColorRole.NoRole)
            self.setBackground(background)

            self.setFocusPolicy(QtCore.Qt.FocusPolicy.StrongFocus)
            self.setFrameShape(QtWidgets.QFrame.Shape.NoFrame)
            self.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
            self.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
            self.setTransformationAnchor(QtWidgets.QGraphicsView.ViewportAnchor.NoAnchor)
            self.setResizeAnchor(QtWidgets.QGraphicsView.ViewportAnchor.AnchorViewCenter)
            self.setViewportUpdateMode(QtWidgets.QGraphicsView.ViewportUpdateMode.MinimalViewportUpdate)

            self.lockedViewports = []
            self.lastMousePos = None
            self.setMouseTracking(True)
            self.aspectLocked = False
            self.range = QtCore.QRectF(0, 0, 1, 1)
            self.autoPixelRange = True
            self.currentItem = None
            self.clearMouse()
            self.updateMatrix()
            # GraphicsScene must have parent or expect crashes!
            self.sceneObj = GraphicsScene(parent=self)
            self.setScene(self.sceneObj)

            ## by default we set up a central widget with a grid layout.
            ## this can be replaced if needed.
            self.centralWidget = None
            self.setCentralItem(QtWidgets.QGraphicsWidget())
            self.centralLayout = QtWidgets.QGraphicsGridLayout()
            self.centralWidget.setLayout(self.centralLayout)

            self.mouseEnabled = False
            self.scaleCenter = False  ## should scaling center around view center (True) or mouse click (False)
            self.clickAccepted = False

        def setAntialiasing(self, aa):
            """Enable or disable default antialiasing.
            Note that this will only affect items that do not specify their own antialiasing options."""
            if aa:
                self.setRenderHints(self.renderHints() | QtGui.QPainter.RenderHint.Antialiasing)
            else:
                self.setRenderHints(self.renderHints() & ~QtGui.QPainter.RenderHint.Antialiasing)

        def setBackground(self, background):
            """
            Set the background color of the GraphicsView.
            To use the defaults specified py pyqtgraph.setConfigOption, use background='default'.
            To make the background transparent, use background=None.
            """
            self._background = background
            if background == 'default':
                background = getConfigOption('background')
            brush = fn.mkBrush(background)
            self.setBackgroundBrush(brush)

        def paintEvent(self, ev):
            self.scene().prepareForPaint()
            return super().paintEvent(ev)

        def render(self, *args, **kwds):
            self.scene().prepareForPaint()
            return super().render(*args, **kwds)

        def close(self):
            self.centralWidget = None
            self.scene().clear()
            self.currentItem = None
            self.sceneObj = None
            self.closed = True
            self.setViewport(None)
            super(GraphicsView, self).close()

        def useOpenGL(self, b=True):
            old_vp = self.viewport()
            new_vp = None

            if b:
                if not isinstance(old_vp, OpenGLHelpers.GraphicsViewGLWidget):
                    new_vp = OpenGLHelpers.GraphicsViewGLWidget()
            else:
                if not type(old_vp) is QtWidgets.QWidget:
                    new_vp = QtWidgets.QWidget()

            if new_vp is not None:
                self.setViewport(new_vp)

        def keyPressEvent(self, ev):
            self.scene().keyPressEvent(ev)  ## bypass view, hand event directly to scene
                                            ## (view likes to eat arrow key events)

        def setCentralItem(self, item):
            return self.setCentralWidget(item)

        def setCentralWidget(self, item):
            """Sets a QGraphicsWidget to automatically fill the entire view (the item will be automatically
            resize whenever the GraphicsView is resized)."""
            if self.centralWidget is not None:
                self.scene().removeItem(self.centralWidget)
            self.centralWidget = item
            if item is not None:
                self.sceneObj.addItem(item)
                self.resizeEvent(None)

        def addItem(self, *args):
            return self.scene().addItem(*args)

        def removeItem(self, *args):
            return self.scene().removeItem(*args)

        def enableMouse(self, b=True):
            self.mouseEnabled = b
            self.autoPixelRange = (not b)

        def clearMouse(self):
            self.mouseTrail = []
            self.lastButtonReleased = None

        def resizeEvent(self, ev):
            if self.closed:
                return
            if self.autoPixelRange:
                self.range = QtCore.QRectF(0, 0, self.size().width(), self.size().height())
            GraphicsView.setRange(self, self.range, padding=0, disableAutoPixel=False)  ## we do this because some subclasses like to redefine setRange in an incompatible way.
            self.updateMatrix()

        def updateMatrix(self, propagate=True):
            self.setSceneRect(self.range)
            if self.autoPixelRange:
                self.resetTransform()
            else:
                if self.aspectLocked:
                    self.fitInView(self.range, QtCore.Qt.AspectRatioMode.KeepAspectRatio)
                else:
                    self.fitInView(self.range, QtCore.Qt.AspectRatioMode.IgnoreAspectRatio)

            if propagate:
                for v in self.lockedViewports:
                    v.setXRange(self.range, padding=0)

            self.sigDeviceRangeChanged.emit(self, self.range)
            self.sigDeviceTransformChanged.emit(self)

        def viewRect(self):
            """Return the boundaries of the view in scene coordinates"""
            ## easier to just return self.range ?
            r = QtCore.QRectF(self.rect())
            return self.viewportTransform().inverted()[0].mapRect(r)

        def visibleRange(self):
            ## for backward compatibility
            return self.viewRect()

        def translate(self, dx, dy):
            self.range.adjust(dx, dy, dx, dy)
            self.updateMatrix()

        def scale(self, sx, sy, center=None):
            scale = [sx, sy]
            if self.aspectLocked:
                scale[0] = scale[1]

            if self.scaleCenter:
                center = None
            if center is None:
                center = self.range.center()

            w = self.range.width()  / scale[0]
            h = self.range.height() / scale[1]
            self.range = QtCore.QRectF(center.x() - (center.x()-self.range.left()) / scale[0], center.y() - (center.y()-self.range.top())  /scale[1], w, h)

            self.updateMatrix()
            self.sigScaleChanged.emit(self)

        def setRange(self, newRect=None, padding=0.05, lockAspect=None, propagate=True, disableAutoPixel=True):
            if disableAutoPixel:
                self.autoPixelRange=False
            if newRect is None:
                newRect = self.visibleRange()
                padding = 0

            padding = Point(padding)
            newRect = QtCore.QRectF(newRect)
            pw = newRect.width() * padding[0]
            ph = newRect.height() * padding[1]
            newRect = newRect.adjusted(-pw, -ph, pw, ph)
            scaleChanged = False
            if self.range.width() != newRect.width() or self.range.height() != newRect.height():
                scaleChanged = True
            self.range = newRect
            #print "New Range:", self.range
            if self.centralWidget is not None:
                self.centralWidget.setGeometry(self.range)
            self.updateMatrix(propagate)
            if scaleChanged:
                self.sigScaleChanged.emit(self)

        def scaleToImage(self, image):
            """Scales such that pixels in image are the same size as screen pixels. This may result in a significant performance increase."""
            pxSize = image.pixelSize()
            image.setPxMode(True)
            try:
                self.sigScaleChanged.disconnect(image.setScaledMode)
            except (TypeError, RuntimeError):
                pass
            tl = image.sceneBoundingRect().topLeft()
            w = self.size().width() * pxSize[0]
            h = self.size().height() * pxSize[1]
            range = QtCore.QRectF(tl.x(), tl.y(), w, h)
            GraphicsView.setRange(self, range, padding=0)
            self.sigScaleChanged.connect(image.setScaledMode)

        def lockXRange(self, v1):
            if not v1 in self.lockedViewports:
                self.lockedViewports.append(v1)

        def setXRange(self, r, padding=0.05):
            r1 = QtCore.QRectF(self.range)
            r1.setLeft(r.left())
            r1.setRight(r.right())
            GraphicsView.setRange(self, r1, padding=[padding, 0], propagate=False)

        def setYRange(self, r, padding=0.05):
            r1 = QtCore.QRectF(self.range)
            r1.setTop(r.top())
            r1.setBottom(r.bottom())
            GraphicsView.setRange(self, r1, padding=[0, padding], propagate=False)

        def wheelEvent(self, ev):
            super().wheelEvent(ev)
            if not self.mouseEnabled:
                return
            delta = ev.angleDelta().x()
            if delta == 0:
                delta = ev.angleDelta().y()

            sc = 1.001 ** delta
            #self.scale *= sc
            #self.updateMatrix()
            self.scale(sc, sc)

        def setAspectLocked(self, s):
            self.aspectLocked = s

        def leaveEvent(self, ev):
            self.scene().leaveEvent(ev)  ## inform scene when mouse leaves

        def mousePressEvent(self, ev):
            super().mousePressEvent(ev)

            if not self.mouseEnabled:
                return
            lpos = ev.position() if hasattr(ev, 'position') else ev.localPos()
            self.lastMousePos = lpos
            self.mousePressPos = lpos
            self.clickAccepted = ev.isAccepted()
            if not self.clickAccepted:
                self.scene().clearSelection()
            return   ## Everything below disabled for now..

        def mouseReleaseEvent(self, ev):
            super().mouseReleaseEvent(ev)
            if not self.mouseEnabled:
                return
            self.sigMouseReleased.emit(ev)
            self.lastButtonReleased = ev.button()
            return   ## Everything below disabled for now..

        def mouseMoveEvent(self, ev):
            lpos = ev.position() if hasattr(ev, 'position') else ev.localPos()
            if self.lastMousePos is None:
                self.lastMousePos = lpos
            delta = Point(lpos - self.lastMousePos)
            self.lastMousePos = lpos

            super().mouseMoveEvent(ev)
            if not self.mouseEnabled:
                return
            self.sigSceneMouseMoved.emit(self.mapToScene(lpos.toPoint()))

            if self.clickAccepted:  ## Ignore event if an item in the scene has already claimed it.
                return

            if ev.buttons() == QtCore.Qt.MouseButton.RightButton:
                delta = Point(fn.clip_scalar(delta[0], -50, 50), fn.clip_scalar(-delta[1], -50, 50))
                scale = 1.01 ** delta
                self.scale(scale[0], scale[1], center=self.mapToScene(self.mousePressPos.toPoint()))
                self.sigDeviceRangeChanged.emit(self, self.range)

            elif ev.buttons() in [QtCore.Qt.MouseButton.MiddleButton, QtCore.Qt.MouseButton.LeftButton]:  ## Allow panning by left or mid button.
                px = self.pixelSize()
                tr = -delta * px

                self.translate(tr[0], tr[1])
                self.sigDeviceRangeChanged.emit(self, self.range)

        def pixelSize(self):
            """Return vector with the length and width of one view pixel in scene coordinates"""
            p0 = Point(0,0)
            p1 = Point(1,1)
            tr = self.transform().inverted()[0]
            p01 = tr.map(p0)
            p11 = tr.map(p1)
            return Point(p11 - p01)

        def dragEnterEvent(self, ev):
            ev.ignore()  ## not sure why, but for some reason this class likes to consume drag events