text: # -*- coding: utf-8 -*-
  """
  GraphicsView.py -   Extension of QGraphicsView
  Copyright 2010  Luke Campagnola
  Distributed under MIT/X11 license. See license.txt for more information.
  """
  
  from ..Qt import QtCore, QtGui, QtWidgets, QT_LIB
  from ..Point import Point
  from ..GraphicsScene import GraphicsScene
  from .. import functions as fn
  from .. import debug as debug
  from .. import getConfigOption
  
  __all__ = ['GraphicsView']
  
  
  class GraphicsView(QtGui.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
          
          QtGui.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.CacheBackground)
          
          ## This might help, but it's probably dangerous in the general case..
          #self.setOptimizationFlag(self.DontSavePainterState, True)
          
          self.setBackgroundRole(QtGui.QPalette.NoRole)
          self.setBackground(background)
          
          self.setFocusPolicy(QtCore.Qt.StrongFocus)
          self.setFrameShape(QtGui.QFrame.NoFrame)
          self.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
          self.setHorizontalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOff)
          self.setTransformationAnchor(QtGui.QGraphicsView.NoAnchor)
          self.setResizeAnchor(QtGui.QGraphicsView.AnchorViewCenter)
          self.setViewportUpdateMode(QtGui.QGraphicsView.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)
          
          ## Workaround for PySide crash
          ## This ensures that the scene will outlive the view.
          if QT_LIB == 'PySide':
              self.sceneObj._view_ref_workaround = self
          
          ## by default we set up a central widget with a grid layout.
          ## this can be replaced if needed.
          self.centralWidget = None
          self.setCentralItem(QtGui.QGraphicsWidget())
          self.centralLayout = QtGui.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.Antialiasing)
          else:
              self.setRenderHints(self.renderHints() & ~QtGui.QPainter.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):
          if b:
              HAVE_OPENGL = hasattr(QtWidgets, 'QOpenGLWidget')
              if not HAVE_OPENGL:
                  raise Exception("Requested to use OpenGL with QGraphicsView, but QOpenGLWidget is not available.")
  
              v = QtWidgets.QOpenGLWidget()
          else:
              v = QtGui.QWidget()
              
          self.setViewport(v)
              
      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.KeepAspectRatio)
              else:
                  self.fitInView(self.range, QtCore.Qt.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 = 0
          if QT_LIB in ['PyQt4', 'PySide']:
              delta = ev.delta()
          else:
              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.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.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))
              
          if self.clickAccepted:  ## Ignore event if an item in the scene has already claimed it.
              return
          
          if ev.buttons() == QtCore.Qt.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))
              self.sigDeviceRangeChanged.emit(self, self.range)
  
          elif ev.buttons() in [QtCore.Qt.MiddleButton, QtCore.Qt.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
  