# Source code for pyqtgraph.widgets.RemoteGraphicsView

    from ..Qt import QtGui, QtCore, USE_PYSIDE
    if not USE_PYSIDE:
        import sip
    from .. import multiprocess as mp
    from .GraphicsView import GraphicsView
    from .. import CONFIG_OPTIONS
    import numpy as np
    import mmap, tempfile, ctypes, atexit, sys, random

    __all__ = ['RemoteGraphicsView']

    class RemoteGraphicsView(QtGui.QWidget):
        """
        Replacement for GraphicsView that does all scene management and rendering on a remote process,
        while displaying on the local widget.

        GraphicsItems must be created by proxy to the remote process.

        """
        def __init__(self, parent=None, *args, **kwds):
            """
            The keyword arguments 'useOpenGL' and 'backgound', if specified, are passed to the remote
            GraphicsView.__init__(). All other keyword arguments are passed to multiprocess.QtProcess.__init__().
            """
            self._img = None
            self._imgReq = None
            self._sizeHint = (640,480)  ## no clue why this is needed, but it seems to be the default sizeHint for GraphicsView.
                                        ## without it, the widget will not compete for space against another GraphicsView.
            QtGui.QWidget.__init__(self)

            # separate local keyword arguments from remote.
            remoteKwds = {}
            for kwd in ['useOpenGL', 'background']:
                if kwd in kwds:
                    remoteKwds[kwd] = kwds.pop(kwd)

            self._proc = mp.QtProcess(**kwds)
            self.pg = self._proc._import('pyqtgraph')
            self.pg.setConfigOptions(**CONFIG_OPTIONS)
            rpgRemote = self._proc._import('pyqtgraph.widgets.RemoteGraphicsView')
            self._view = rpgRemote.Renderer(*args, **remoteKwds)
            self._view._setProxyOptions(deferGetattr=True)

            self.setFocusPolicy(QtCore.Qt.StrongFocus)
            self.setSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding)
            self.setMouseTracking(True)
            self.shm = None
            shmFileName = self._view.shmFileName()
            if sys.platform.startswith('win'):
                self.shmtag = shmFileName
            else:
                self.shmFile = open(shmFileName, 'r')

            self._view.sceneRendered.connect(mp.proxy(self.remoteSceneChanged)) #, callSync='off'))
                                                                                ## Note: we need synchronous signals
                                                                                ## even though there is no return value--
                                                                                ## this informs the renderer that it is
                                                                                ## safe to begin rendering again.

            for method in ['scene', 'setCentralItem']:
                setattr(self, method, getattr(self._view, method))

        def resizeEvent(self, ev):
            ret = QtGui.QWidget.resizeEvent(self, ev)
            self._view.resize(self.size(), _callSync='off')
            return ret

        def sizeHint(self):
            return QtCore.QSize(*self._sizeHint)

        def remoteSceneChanged(self, data):
            w, h, size, newfile = data
            #self._sizeHint = (whint, hhint)
            if self.shm is None or self.shm.size != size:
                if self.shm is not None:
                    self.shm.close()
                if sys.platform.startswith('win'):
                    self.shmtag = newfile   ## on windows, we create a new tag for every resize
                    self.shm = mmap.mmap(-1, size, self.shmtag) ## can't use tmpfile on windows because the file can only be opened once.
                else:
                    self.shm = mmap.mmap(self.shmFile.fileno(), size, mmap.MAP_SHARED, mmap.PROT_READ)
            self.shm.seek(0)
            data = self.shm.read(w*h*4)
            self._img = QtGui.QImage(data, w, h, QtGui.QImage.Format_ARGB32)
            self._img.data = data  # data must be kept alive or PySide 1.2.1 (and probably earlier) will crash.
            self.update()

        def paintEvent(self, ev):
            if self._img is None:
                return
            p = QtGui.QPainter(self)
            p.drawImage(self.rect(), self._img, QtCore.QRect(0, 0, self._img.width(), self._img.height()))
            p.end()

        def mousePressEvent(self, ev):
            self._view.mousePressEvent(int(ev.type()), ev.pos(), ev.globalPos(), int(ev.button()), int(ev.buttons()), int(ev.modifiers()), _callSync='off')
            ev.accept()
            return QtGui.QWidget.mousePressEvent(self, ev)

        def mouseReleaseEvent(self, ev):
            self._view.mouseReleaseEvent(int(ev.type()), ev.pos(), ev.globalPos(), int(ev.button()), int(ev.buttons()), int(ev.modifiers()), _callSync='off')
            ev.accept()
            return QtGui.QWidget.mouseReleaseEvent(self, ev)

        def mouseMoveEvent(self, ev):
            self._view.mouseMoveEvent(int(ev.type()), ev.pos(), ev.globalPos(), int(ev.button()), int(ev.buttons()), int(ev.modifiers()), _callSync='off')
            ev.accept()
            return QtGui.QWidget.mouseMoveEvent(self, ev)

        def wheelEvent(self, ev):
            self._view.wheelEvent(ev.pos(), ev.globalPos(), ev.delta(), int(ev.buttons()), int(ev.modifiers()), int(ev.orientation()), _callSync='off')
            ev.accept()
            return QtGui.QWidget.wheelEvent(self, ev)

        def keyEvent(self, ev):
            if self._view.keyEvent(int(ev.type()), int(ev.modifiers()), text, autorep, count):
                ev.accept()
            return QtGui.QWidget.keyEvent(self, ev)

        def enterEvent(self, ev):
            self._view.enterEvent(int(ev.type()), _callSync='off')
            return QtGui.QWidget.enterEvent(self, ev)

        def leaveEvent(self, ev):
            self._view.leaveEvent(int(ev.type()), _callSync='off')
            return QtGui.QWidget.leaveEvent(self, ev)

        def remoteProcess(self):
            """Return the remote process handle. (see multiprocess.remoteproxy.RemoteEventHandler)"""
            return self._proc

        def close(self):
            """Close the remote process. After this call, the widget will no longer be updated."""
            self._proc.close()

    class Renderer(GraphicsView):
        ## Created by the remote process to handle render requests

        sceneRendered = QtCore.Signal(object)

        def __init__(self, *args, **kwds):
            ## Create shared memory for rendered image
            #pg.dbg(namespace={'r': self})
            if sys.platform.startswith('win'):
                self.shmtag = "pyqtgraph_shmem_" + ''.join([chr((random.getrandbits(20)%25) + 97) for i in range(20)])
                self.shm = mmap.mmap(-1, mmap.PAGESIZE, self.shmtag) # use anonymous mmap on windows
            else:
                self.shmFile = tempfile.NamedTemporaryFile(prefix='pyqtgraph_shmem_')
                self.shmFile.write(b'\x00' * (mmap.PAGESIZE+1))
                fd = self.shmFile.fileno()
                self.shm = mmap.mmap(fd, mmap.PAGESIZE, mmap.MAP_SHARED, mmap.PROT_WRITE)
            atexit.register(self.close)

            GraphicsView.__init__(self, *args, **kwds)
            self.scene().changed.connect(self.update)
            self.img = None
            self.renderTimer = QtCore.QTimer()
            self.renderTimer.timeout.connect(self.renderView)
            self.renderTimer.start(16)

        def close(self):
            self.shm.close()
            if not sys.platform.startswith('win'):
                self.shmFile.close()

        def shmFileName(self):
            if sys.platform.startswith('win'):
                return self.shmtag
            else:
                return self.shmFile.name

        def update(self):
            self.img = None
            return GraphicsView.update(self)

        def resize(self, size):
            oldSize = self.size()
            GraphicsView.resize(self, size)
            self.resizeEvent(QtGui.QResizeEvent(size, oldSize))
            self.update()

        def renderView(self):
            if self.img is None:
                ## make sure shm is large enough and get its address
                if self.width() == 0 or self.height() == 0:
                    return
                size = self.width() * self.height() * 4
                if size > self.shm.size():
                    if sys.platform.startswith('win'):
                        ## windows says "WindowsError: [Error 87] the parameter is incorrect" if we try to resize the mmap
                        self.shm.close()
                        ## it also says (sometimes) 'access is denied' if we try to reuse the tag.
                        self.shmtag = "pyqtgraph_shmem_" + ''.join([chr((random.getrandbits(20)%25) + 97) for i in range(20)])
                        self.shm = mmap.mmap(-1, size, self.shmtag)
                    else:
                        self.shm.resize(size)

                ## render the scene directly to shared memory
                if USE_PYSIDE:
                    ch = ctypes.c_char.from_buffer(self.shm, 0)
                    #ch = ctypes.c_char_p(address)
                    self.img = QtGui.QImage(ch, self.width(), self.height(), QtGui.QImage.Format_ARGB32)
                else:
                    address = ctypes.addressof(ctypes.c_char.from_buffer(self.shm, 0))

                    # different versions of pyqt have different requirements here..
                    try:
                        self.img = QtGui.QImage(sip.voidptr(address), self.width(), self.height(), QtGui.QImage.Format_ARGB32)
                    except TypeError:
                        try:
                            self.img = QtGui.QImage(memoryview(buffer(self.shm)), self.width(), self.height(), QtGui.QImage.Format_ARGB32)
                        except TypeError:
                            # Works on PyQt 4.9.6
                            self.img = QtGui.QImage(address, self.width(), self.height(), QtGui.QImage.Format_ARGB32)
                self.img.fill(0xffffffff)
                p = QtGui.QPainter(self.img)
                self.render(p, self.viewRect(), self.rect())
                p.end()
                self.sceneRendered.emit((self.width(), self.height(), self.shm.size(), self.shmFileName()))

        def mousePressEvent(self, typ, pos, gpos, btn, btns, mods):
            typ = QtCore.QEvent.Type(typ)
            btn = QtCore.Qt.MouseButton(btn)
            btns = QtCore.Qt.MouseButtons(btns)
            mods = QtCore.Qt.KeyboardModifiers(mods)
            return GraphicsView.mousePressEvent(self, QtGui.QMouseEvent(typ, pos, gpos, btn, btns, mods))

        def mouseMoveEvent(self, typ, pos, gpos, btn, btns, mods):
            typ = QtCore.QEvent.Type(typ)
            btn = QtCore.Qt.MouseButton(btn)
            btns = QtCore.Qt.MouseButtons(btns)
            mods = QtCore.Qt.KeyboardModifiers(mods)
            return GraphicsView.mouseMoveEvent(self, QtGui.QMouseEvent(typ, pos, gpos, btn, btns, mods))

        def mouseReleaseEvent(self, typ, pos, gpos, btn, btns, mods):
            typ = QtCore.QEvent.Type(typ)
            btn = QtCore.Qt.MouseButton(btn)
            btns = QtCore.Qt.MouseButtons(btns)
            mods = QtCore.Qt.KeyboardModifiers(mods)
            return GraphicsView.mouseReleaseEvent(self, QtGui.QMouseEvent(typ, pos, gpos, btn, btns, mods))

        def wheelEvent(self, pos, gpos, d, btns, mods, ori):
            btns = QtCore.Qt.MouseButtons(btns)
            mods = QtCore.Qt.KeyboardModifiers(mods)
            ori = (None, QtCore.Qt.Horizontal, QtCore.Qt.Vertical)[ori]
            return GraphicsView.wheelEvent(self, QtGui.QWheelEvent(pos, gpos, d, btns, mods, ori))

        def keyEvent(self, typ, mods, text, autorep, count):
            typ = QtCore.QEvent.Type(typ)
            mods = QtCore.Qt.KeyboardModifiers(mods)
            GraphicsView.keyEvent(self, QtGui.QKeyEvent(typ, mods, text, autorep, count))
            return ev.accepted()

        def enterEvent(self, typ):
            ev = QtCore.QEvent(QtCore.QEvent.Type(typ))
            return GraphicsView.enterEvent(self, ev)

        def leaveEvent(self, typ):
            ev = QtCore.QEvent(QtCore.QEvent.Type(typ))
            return GraphicsView.leaveEvent(self, ev)