# -*- coding: utf-8 -*-
import sys
import warnings
import weakref
import numpy as np
import os
from ...Qt import QtGui, QtCore, QT_LIB
from ... import pixmaps
from ... import functions as fn
from ...widgets.FileDialog import FileDialog
from .. PlotDataItem import PlotDataItem
from .. ViewBox import ViewBox
from .. AxisItem import AxisItem
from .. LabelItem import LabelItem
from .. LegendItem import LegendItem
from .. GraphicsWidget import GraphicsWidget
from .. ButtonItem import ButtonItem
from .. InfiniteLine import InfiniteLine
from ...WidgetGroup import WidgetGroup
from ...python2_3 import basestring

if QT_LIB == 'PyQt4':
    from .plotConfigTemplate_pyqt import *
elif QT_LIB == 'PySide':
    from .plotConfigTemplate_pyside import *
elif QT_LIB == 'PyQt5':
    from .plotConfigTemplate_pyqt5 import *
elif QT_LIB == 'PySide2':
    from .plotConfigTemplate_pyside2 import *

__all__ = ['PlotItem']

try:
    from metaarray import *
    HAVE_METAARRAY = True
except:
    HAVE_METAARRAY = False


class PlotItem(GraphicsWidget):
    """GraphicsWidget implementing a standard 2D plotting area with axes.

    **Bases:** :class:`GraphicsWidget <pyqtgraph.GraphicsWidget>`
    
    This class provides the ViewBox-plus-axes that appear when using
    :func:`pg.plot() <pyqtgraph.plot>`, :class:`PlotWidget <pyqtgraph.PlotWidget>`,
    and :func:`GraphicsLayoutWidget.addPlot() <pyqtgraph.GraphicsLayoutWidget.addPlot>`.

    It's main functionality is:

    - Manage placement of ViewBox, AxisItems, and LabelItems
    - Create and manage a list of PlotDataItems displayed inside the ViewBox
    - Implement a context menu with commonly used display and analysis options

    Use :func:`plot() <pyqtgraph.PlotItem.plot>` to create a new PlotDataItem and
    add it to the view. Use :func:`addItem() <pyqtgraph.PlotItem.addItem>` to
    add any QGraphicsItem to the view.
    
    This class wraps several methods from its internal ViewBox:
    :func:`setXRange <pyqtgraph.ViewBox.setXRange>`,
    :func:`setYRange <pyqtgraph.ViewBox.setYRange>`,
    :func:`setRange <pyqtgraph.ViewBox.setRange>`,
    :func:`autoRange <pyqtgraph.ViewBox.autoRange>`,
    :func:`setXLink <pyqtgraph.ViewBox.setXLink>`,
    :func:`setYLink <pyqtgraph.ViewBox.setYLink>`,
    :func:`setAutoPan <pyqtgraph.ViewBox.setAutoPan>`,
    :func:`setAutoVisible <pyqtgraph.ViewBox.setAutoVisible>`,
    :func:`setLimits <pyqtgraph.ViewBox.setLimits>`,
    :func:`viewRect <pyqtgraph.ViewBox.viewRect>`,
    :func:`viewRange <pyqtgraph.ViewBox.viewRange>`,
    :func:`setMouseEnabled <pyqtgraph.ViewBox.setMouseEnabled>`,
    :func:`enableAutoRange <pyqtgraph.ViewBox.enableAutoRange>`,
    :func:`disableAutoRange <pyqtgraph.ViewBox.disableAutoRange>`,
    :func:`setAspectLocked <pyqtgraph.ViewBox.setAspectLocked>`,
    :func:`invertY <pyqtgraph.ViewBox.invertY>`,
    :func:`invertX <pyqtgraph.ViewBox.invertX>`,
    :func:`register <pyqtgraph.ViewBox.register>`,
    :func:`unregister <pyqtgraph.ViewBox.unregister>`
    
    The ViewBox itself can be accessed by calling :func:`getViewBox() <pyqtgraph.PlotItem.getViewBox>` 
    
    ==================== =======================================================================
    **Signals:**
    sigYRangeChanged     wrapped from :class:`ViewBox <pyqtgraph.ViewBox>`
    sigXRangeChanged     wrapped from :class:`ViewBox <pyqtgraph.ViewBox>`
    sigRangeChanged      wrapped from :class:`ViewBox <pyqtgraph.ViewBox>`
    ==================== =======================================================================
    """
    
    sigRangeChanged = QtCore.Signal(object, object)    ## Emitted when the ViewBox range has changed
    sigYRangeChanged = QtCore.Signal(object, object)   ## Emitted when the ViewBox Y range has changed
    sigXRangeChanged = QtCore.Signal(object, object)   ## Emitted when the ViewBox X range has changed
        
    lastFileDir = None
    
    def __init__(self, parent=None, name=None, labels=None, title=None, viewBox=None, axisItems=None, enableMenu=True, **kargs):
        """
        Create a new PlotItem. All arguments are optional.
        Any extra keyword arguments are passed to :func:`PlotItem.plot() <pyqtgraph.PlotItem.plot>`.
        
        ==============  ==========================================================================================
        **Arguments:**
        *title*         Title to display at the top of the item. Html is allowed.
        *labels*        A dictionary specifying the axis labels to display::
                   
                            {'left': (args), 'bottom': (args), ...}
                     
                        The name of each axis and the corresponding arguments are passed to 
                        :func:`PlotItem.setLabel() <pyqtgraph.PlotItem.setLabel>`
                        Optionally, PlotItem my also be initialized with the keyword arguments left,
                        right, top, or bottom to achieve the same effect.
        *name*          Registers a name for this view so that others may link to it
        *viewBox*       If specified, the PlotItem will be constructed with this as its ViewBox.
        *axisItems*     Optional dictionary instructing the PlotItem to use pre-constructed items
                        for its axes. The dict keys must be axis names ('left', 'bottom', 'right', 'top')
                        and the values must be instances of AxisItem (or at least compatible with AxisItem).
        ==============  ==========================================================================================
        """
        
        GraphicsWidget.__init__(self, parent)
        
        self.setSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding)
        
        ## Set up control buttons
        path = os.path.dirname(__file__)
        self.autoBtn = ButtonItem(pixmaps.getPixmap('auto'), 14, self)
        self.autoBtn.mode = 'auto'
        self.autoBtn.clicked.connect(self.autoBtnClicked)
        self.buttonsHidden = False ## whether the user has requested buttons to be hidden
        self.mouseHovering = False
        
        self.layout = QtGui.QGraphicsGridLayout()
        self.layout.setContentsMargins(1,1,1,1)
        self.setLayout(self.layout)
        self.layout.setHorizontalSpacing(0)
        self.layout.setVerticalSpacing(0)
        
        if viewBox is None:
            viewBox = ViewBox(parent=self)
        self.vb = viewBox
        self.vb.sigStateChanged.connect(self.viewStateChanged)
        self.setMenuEnabled(enableMenu, enableMenu) ## en/disable plotitem and viewbox menus
        
        if name is not None:
            self.vb.register(name)
        self.vb.sigRangeChanged.connect(self.sigRangeChanged)
        self.vb.sigXRangeChanged.connect(self.sigXRangeChanged)
        self.vb.sigYRangeChanged.connect(self.sigYRangeChanged)
        
        self.layout.addItem(self.vb, 2, 1)
        self.alpha = 1.0
        self.autoAlpha = True
        self.spectrumMode = False
        
        self.legend = None
        
        # Initialize axis items
        self.axes = {}
        self.setAxisItems(axisItems)
        
        self.titleLabel = LabelItem('', size='11pt', parent=self)
        self.layout.addItem(self.titleLabel, 0, 1)
        self.setTitle(None)  ## hide
        
        for i in range(4):
            self.layout.setRowPreferredHeight(i, 0)
            self.layout.setRowMinimumHeight(i, 0)
            self.layout.setRowSpacing(i, 0)
            self.layout.setRowStretchFactor(i, 1)
            
        for i in range(3):
            self.layout.setColumnPreferredWidth(i, 0)
            self.layout.setColumnMinimumWidth(i, 0)
            self.layout.setColumnSpacing(i, 0)
            self.layout.setColumnStretchFactor(i, 1)
        self.layout.setRowStretchFactor(2, 100)
        self.layout.setColumnStretchFactor(1, 100)
        

        self.items = []
        self.curves = []
        self.itemMeta = weakref.WeakKeyDictionary()
        self.dataItems = []
        self.paramList = {}
        self.avgCurves = {}
        
        ### Set up context menu
        
        w = QtGui.QWidget()
        self.ctrl = c = Ui_Form()
        c.setupUi(w)
        dv = QtGui.QDoubleValidator(self)
        
        menuItems = [
            ('Transforms', c.transformGroup),
            ('Downsample', c.decimateGroup),
            ('Average', c.averageGroup),
            ('Alpha', c.alphaGroup),
            ('Grid', c.gridGroup),
            ('Points', c.pointsGroup),
        ]
        
        
        self.ctrlMenu = QtGui.QMenu()
        
        self.ctrlMenu.setTitle('Plot Options')
        self.subMenus = []
        for name, grp in menuItems:
            sm = QtGui.QMenu(name)
            act = QtGui.QWidgetAction(self)
            act.setDefaultWidget(grp)
            sm.addAction(act)
            self.subMenus.append(sm)
            self.ctrlMenu.addMenu(sm)
        
        self.stateGroup = WidgetGroup()
        for name, w in menuItems:
            self.stateGroup.autoAdd(w)
        
        self.fileDialog = None
        
        c.alphaGroup.toggled.connect(self.updateAlpha)
        c.alphaSlider.valueChanged.connect(self.updateAlpha)
        c.autoAlphaCheck.toggled.connect(self.updateAlpha)

        c.xGridCheck.toggled.connect(self.updateGrid)
        c.yGridCheck.toggled.connect(self.updateGrid)
        c.gridAlphaSlider.valueChanged.connect(self.updateGrid)

        c.fftCheck.toggled.connect(self.updateSpectrumMode)
        c.logXCheck.toggled.connect(self.updateLogMode)
        c.logYCheck.toggled.connect(self.updateLogMode)
        c.derivativeCheck.toggled.connect(self.updateDerivativeMode)
        c.phasemapCheck.toggled.connect(self.updatePhasemapMode)

        c.downsampleSpin.valueChanged.connect(self.updateDownsampling)
        c.downsampleCheck.toggled.connect(self.updateDownsampling)
        c.autoDownsampleCheck.toggled.connect(self.updateDownsampling)
        c.subsampleRadio.toggled.connect(self.updateDownsampling)
        c.meanRadio.toggled.connect(self.updateDownsampling)
        c.clipToViewCheck.toggled.connect(self.updateDownsampling)

        self.ctrl.avgParamList.itemClicked.connect(self.avgParamListClicked)
        self.ctrl.averageGroup.toggled.connect(self.avgToggled)
        
        self.ctrl.maxTracesCheck.toggled.connect(self.updateDecimation)
        self.ctrl.maxTracesSpin.valueChanged.connect(self.updateDecimation)
        
        if labels is None:
            labels = {}
        for label in list(self.axes.keys()):
            if label in kargs:
                labels[label] = kargs[label]
                del kargs[label]
        for k in labels:
            if isinstance(labels[k], basestring):
                labels[k] = (labels[k],)
            self.setLabel(k, *labels[k])
                
        if title is not None:
            self.setTitle(title)
        
        if len(kargs) > 0:
            self.plot(**kargs)        
        
    def implements(self, interface=None):
        return interface in ['ViewBoxWrapper']

    def getViewBox(self):
        """Return the :class:`ViewBox <pyqtgraph.ViewBox>` contained within."""
        return self.vb
    
    ## Wrap a few methods from viewBox. 
    #Important: don't use a settattr(m, getattr(self.vb, m)) as we'd be leaving the viebox alive
    #because we had a reference to an instance method (creating wrapper methods at runtime instead).
    for m in ['setXRange', 'setYRange', 'setXLink', 'setYLink', 'setAutoPan',         # NOTE: 
              'setAutoVisible', 'setRange', 'autoRange', 'viewRect', 'viewRange',     # If you update this list, please 
              'setMouseEnabled', 'setLimits', 'enableAutoRange', 'disableAutoRange',  # update the class docstring 
              'setAspectLocked', 'invertY', 'invertX', 'register', 'unregister']:                # as well.
                
        def _create_method(name):
            def method(self, *args, **kwargs):
                return getattr(self.vb, name)(*args, **kwargs)
            method.__name__ = name
            return method
        
        locals()[m] = _create_method(m)
        
    del _create_method
    
    def setAxisItems(self, axisItems=None):
        """
        Place axis items as given by `axisItems`. Initializes non-existing axis items.
        
        ==============  ==========================================================================================
        **Arguments:**
        *axisItems*     Optional dictionary instructing the PlotItem to use pre-constructed items
                        for its axes. The dict keys must be axis names ('left', 'bottom', 'right', 'top')
                        and the values must be instances of AxisItem (or at least compatible with AxisItem).
        ==============  ==========================================================================================
        """
        
                
        if axisItems is None:
            axisItems = {}
        
        # Array containing visible axis items
        # Also containing potentially hidden axes, but they are not touched so it does not matter
        visibleAxes = ['left', 'bottom']
        visibleAxes.extend(axisItems.keys()) # Note that it does not matter that this adds
                                             # some values to visibleAxes a second time
        
        for k, pos in (('top', (1,1)), ('bottom', (3,1)), ('left', (2,0)), ('right', (2,2))):
            if k in self.axes:
                if k not in axisItems:
                    continue # Nothing to do here
                
                # Remove old axis
                oldAxis = self.axes[k]['item']
                self.layout.removeItem(oldAxis)
                oldAxis.scene().removeItem(oldAxis)
                oldAxis.unlinkFromView()
            
            # Create new axis
            if k in axisItems:
                axis = axisItems[k]
                if axis.scene() is not None:
                    if k not in self.axes or axis != self.axes[k]["item"]:
                        raise RuntimeError(
                            "Can't add an axis to multiple plots. Shared axes"
                            " can be achieved with multiple AxisItem instances"
                            " and set[X/Y]Link.")
            else:
                axis = AxisItem(orientation=k, parent=self)
            
            # Set up new axis
            axis.linkToView(self.vb)
            self.axes[k] = {'item': axis, 'pos': pos}
            self.layout.addItem(axis, *pos)
            axis.setZValue(-1000)
            axis.setFlag(axis.ItemNegativeZStacksBehindParent)
            
            axisVisible = k in visibleAxes
            self.showAxis(k, axisVisible)
        
    def setLogMode(self, x=None, y=None):
        """
        Set log scaling for x and/or y axes.
        This informs PlotDataItems to transform logarithmically and switches
        the axes to use log ticking. 
        
        Note that *no other items* in the scene will be affected by
        this; there is (currently) no generic way to redisplay a GraphicsItem
        with log coordinates.
        
        """
        if x is not None:
            self.ctrl.logXCheck.setChecked(x)
        if y is not None:
            self.ctrl.logYCheck.setChecked(y)
        
    def showGrid(self, x=None, y=None, alpha=None):
        """
        Show or hide the grid for either axis.
        
        ==============  =====================================
        **Arguments:**
        x               (bool) Whether to show the X grid
        y               (bool) Whether to show the Y grid
        alpha           (0.0-1.0) Opacity of the grid
        ==============  =====================================
        """
        if x is None and y is None and alpha is None:
            raise Exception("Must specify at least one of x, y, or alpha.")  ## prevent people getting confused if they just call showGrid()
        
        if x is not None:
            self.ctrl.xGridCheck.setChecked(x)
        if y is not None:
            self.ctrl.yGridCheck.setChecked(y)
        if alpha is not None:
            v = np.clip(alpha, 0, 1)*self.ctrl.gridAlphaSlider.maximum()
            self.ctrl.gridAlphaSlider.setValue(v)
        
    def close(self):
        ## Most of this crap is needed to avoid PySide trouble. 
        ## The problem seems to be whenever scene.clear() leads to deletion of widgets (either through proxies or qgraphicswidgets)
        ## the solution is to manually remove all widgets before scene.clear() is called
        if self.ctrlMenu is None: ## already shut down
            return
        self.ctrlMenu.setParent(None)
        self.ctrlMenu = None
        
        self.autoBtn.setParent(None)
        self.autoBtn = None
        
        for k in self.axes:
            i = self.axes[k]['item']
            i.close()
            
        self.axes = None
        self.scene().removeItem(self.vb)
        self.vb = None
        
    def registerPlot(self, name):   ## for backward compatibility
        self.vb.register(name)
        
    def updateGrid(self, *args):
        alpha = self.ctrl.gridAlphaSlider.value()
        x = alpha if self.ctrl.xGridCheck.isChecked() else False
        y = alpha if self.ctrl.yGridCheck.isChecked() else False
        self.getAxis('top').setGrid(x)
        self.getAxis('bottom').setGrid(x)
        self.getAxis('left').setGrid(y)
        self.getAxis('right').setGrid(y)

    def viewGeometry(self):
        """Return the screen geometry of the viewbox"""
        v = self.scene().views()[0]
        b = self.vb.mapRectToScene(self.vb.boundingRect())
        wr = v.mapFromScene(b).boundingRect()
        pos = v.mapToGlobal(v.pos())
        wr.adjust(pos.x(), pos.y(), pos.x(), pos.y())
        return wr

    def avgToggled(self, b):
        if b:
            self.recomputeAverages()
        for k in self.avgCurves:
            self.avgCurves[k][1].setVisible(b)
        
    def avgParamListClicked(self, item):
        name = str(item.text())
        self.paramList[name] = (item.checkState() == QtCore.Qt.Checked)
        self.recomputeAverages()
        
    def recomputeAverages(self):
        if not self.ctrl.averageGroup.isChecked():
            return
        for k in self.avgCurves:
            self.removeItem(self.avgCurves[k][1])
        self.avgCurves = {}
        for c in self.curves:
            self.addAvgCurve(c)
        self.replot()
        
    def addAvgCurve(self, curve):
        ## Add a single curve into the pool of curves averaged together
        
        ## If there are plot parameters, then we need to determine which to average together.
        remKeys = []
        addKeys = []
        if self.ctrl.avgParamList.count() > 0:
        
            ### First determine the key of the curve to which this new data should be averaged
            for i in range(self.ctrl.avgParamList.count()):
                item = self.ctrl.avgParamList.item(i)
                if item.checkState() == QtCore.Qt.Checked:
                    remKeys.append(str(item.text()))
                else:
                    addKeys.append(str(item.text()))
                    
            if len(remKeys) < 1:  ## In this case, there would be 1 average plot for each data plot; not useful.
                return
                
        p = self.itemMeta.get(curve,{}).copy()
        for k in p:
            if type(k) is tuple:
                p['.'.join(k)] = p[k]
                del p[k]
        for rk in remKeys:
            if rk in p:
                del p[rk]
        for ak in addKeys:
            if ak not in p:
                p[ak] = None
        key = tuple(p.items())
        
        ### Create a new curve if needed
        if key not in self.avgCurves:
            plot = PlotDataItem()
            plot.setPen(fn.mkPen([0, 200, 0]))
            plot.setShadowPen(fn.mkPen([0, 0, 0, 100], width=3))
            plot.setAlpha(1.0, False)
            plot.setZValue(100)
            self.addItem(plot, skipAverage=True)
            self.avgCurves[key] = [0, plot]
        self.avgCurves[key][0] += 1
        (n, plot) = self.avgCurves[key]
        
        ### Average data together
        (x, y) = curve.getData()
        stepMode = curve.opts['stepMode']
        if plot.yData is not None and y.shape == plot.yData.shape:
            # note that if shapes do not match, then the average resets.
            newData = plot.yData * (n-1) / float(n) + y * 1.0 / float(n)
            plot.setData(plot.xData, newData, stepMode=stepMode)
        else:
            plot.setData(x, y, stepMode=stepMode)
        
    def autoBtnClicked(self):
        if self.autoBtn.mode == 'auto':
            self.enableAutoRange()
            self.autoBtn.hide()
        else:
            self.disableAutoRange()
            
    def viewStateChanged(self):
        self.updateButtons()
            
    def enableAutoScale(self):
        """
        Enable auto-scaling. The plot will continuously scale to fit the boundaries of its data.
        """
        print("Warning: enableAutoScale is deprecated. Use enableAutoRange(axis, enable) instead.")
        self.vb.enableAutoRange(self.vb.XYAxes)

    def addItem(self, item, *args, **kargs):
        """
        Add a graphics item to the view box. 
        If the item has plot data (PlotDataItem, PlotCurveItem, ScatterPlotItem), it may
        be included in analysis performed by the PlotItem.
        """
        if item in self.items:
            warnings.warn('Item already added to PlotItem, ignoring.')
            return
        self.items.append(item)
        vbargs = {}
        if 'ignoreBounds' in kargs:
            vbargs['ignoreBounds'] = kargs['ignoreBounds']
        self.vb.addItem(item, *args, **vbargs)
        name = None
        if hasattr(item, 'implements') and item.implements('plotData'):
            name = item.name()
            self.dataItems.append(item)
            #self.plotChanged()
            
            params = kargs.get('params', {})
            self.itemMeta[item] = params
            #item.setMeta(params)
            self.curves.append(item)
            #self.addItem(c)
            
        if hasattr(item, 'setLogMode'):
            item.setLogMode(self.ctrl.logXCheck.isChecked(), self.ctrl.logYCheck.isChecked())
            
        if isinstance(item, PlotDataItem):
            ## configure curve for this plot
            (alpha, auto) = self.alphaState()
            item.setAlpha(alpha, auto)
            item.setFftMode(self.ctrl.fftCheck.isChecked())
            item.setDownsampling(*self.downsampleMode())
            item.setClipToView(self.clipToViewMode())
            item.setPointMode(self.pointMode())
            
            ## Hide older plots if needed
            self.updateDecimation()
            
            ## Add to average if needed
            self.updateParamList()
            if self.ctrl.averageGroup.isChecked() and 'skipAverage' not in kargs:
                self.addAvgCurve(item)
                
            #c.connect(c, QtCore.SIGNAL('plotChanged'), self.plotChanged)
            #item.sigPlotChanged.connect(self.plotChanged)
            #self.plotChanged()
        #name = kargs.get('name', getattr(item, 'opts', {}).get('name', None))
        if name is not None and hasattr(self, 'legend') and self.legend is not None:
            self.legend.addItem(item, name=name)            

    def addDataItem(self, item, *args):
        print("PlotItem.addDataItem is deprecated. Use addItem instead.")
        self.addItem(item, *args)
        
    def listDataItems(self):
        """Return a list of all data items (PlotDataItem, PlotCurveItem, ScatterPlotItem, etc)
        contained in this PlotItem."""
        return self.dataItems[:]
        
    def addCurve(self, c, params=None):
        print("PlotItem.addCurve is deprecated. Use addItem instead.")
        self.addItem(c, params)

    def addLine(self, x=None, y=None, z=None, **kwds):
        """
        Create an InfiniteLine and add to the plot. 
        
        If *x* is specified,
        the line will be vertical. If *y* is specified, the line will be
        horizontal. All extra keyword arguments are passed to
        :func:`InfiniteLine.__init__() <pyqtgraph.InfiniteLine.__init__>`.
        Returns the item created.
        """
        kwds['pos'] = kwds.get('pos', x if x is not None else y)
        kwds['angle'] = kwds.get('angle', 0 if x is None else 90)
        line = InfiniteLine(**kwds)
        self.addItem(line)
        if z is not None:
            line.setZValue(z)
        return line        

    def removeItem(self, item):
        """
        Remove an item from the internal ViewBox.
        """
        if not item in self.items:
            return
        self.items.remove(item)
        if item in self.dataItems:
            self.dataItems.remove(item)
            
        self.vb.removeItem(item)
        
        if item in self.curves:
            self.curves.remove(item)
            self.updateDecimation()
            self.updateParamList()

        if self.legend is not None:
            self.legend.removeItem(item)

    def clear(self):
        """
        Remove all items from the ViewBox.
        """
        for i in self.items[:]:
            self.removeItem(i)
        self.avgCurves = {}
    
    def clearPlots(self):
        for i in self.curves[:]:
            self.removeItem(i)
        self.avgCurves = {}        
    
    def plot(self, *args, **kargs):
        """
        Add and return a new plot.
        See :func:`PlotDataItem.__init__ <pyqtgraph.PlotDataItem.__init__>` for data arguments
        
        Extra allowed arguments are:
            clear    - clear all plots before displaying new data
            params   - meta-parameters to associate with this data
        """
        clear = kargs.get('clear', False)
        params = kargs.get('params', None)
          
        if clear:
            self.clear()
            
        item = PlotDataItem(*args, **kargs)
            
        if params is None:
            params = {}
        self.addItem(item, params=params)
        
        return item

    def addLegend(self, offset=(30, 30), **kwargs):
        """
        Create a new :class:`~pyqtgraph.LegendItem` and anchor it over the
        internal ViewBox. Plots will be automatically displayed in the legend
        if they are created with the 'name' argument.

        If a LegendItem has already been created using this method, that
        item will be returned rather than creating a new one.

        Accepts the same arguments as :meth:`~pyqtgraph.LegendItem`.
        """

        if self.legend is None:
            self.legend = LegendItem(offset=offset, **kwargs)
            self.legend.setParentItem(self.vb)
        return self.legend
        
    def scatterPlot(self, *args, **kargs):
        if 'pen' in kargs:
            kargs['symbolPen'] = kargs['pen']
        kargs['pen'] = None
            
        if 'brush' in kargs:
            kargs['symbolBrush'] = kargs['brush']
            del kargs['brush']
            
        if 'size' in kargs:
            kargs['symbolSize'] = kargs['size']
            del kargs['size']

        return self.plot(*args, **kargs)
                
    def replot(self):
        self.update()

    def updateParamList(self):
        self.ctrl.avgParamList.clear()
        ## Check to see that each parameter for each curve is present in the list
        for c in self.curves:
            for p in list(self.itemMeta.get(c, {}).keys()):
                if type(p) is tuple:
                    p = '.'.join(p)
                    
                ## If the parameter is not in the list, add it.
                matches = self.ctrl.avgParamList.findItems(p, QtCore.Qt.MatchExactly)
                if len(matches) == 0:
                    i = QtGui.QListWidgetItem(p)
                    if p in self.paramList and self.paramList[p] is True:
                        i.setCheckState(QtCore.Qt.Checked)
                    else:
                        i.setCheckState(QtCore.Qt.Unchecked)
                    self.ctrl.avgParamList.addItem(i)
                else:
                    i = matches[0]
                    
                self.paramList[p] = (i.checkState() == QtCore.Qt.Checked)

    def writeSvgCurves(self, fileName=None):
        if fileName is None:
            self._chooseFilenameDialog(handler=self.writeSvg)
            return

        if isinstance(fileName, tuple):
            raise Exception("Not implemented yet..")
        fileName = str(fileName)
        PlotItem.lastFileDir = os.path.dirname(fileName)
        
        rect = self.vb.viewRect()
        xRange = rect.left(), rect.right() 
        
        svg = ""

        dx = max(rect.right(),0) - min(rect.left(),0)
        ymn = min(rect.top(), rect.bottom())
        ymx = max(rect.top(), rect.bottom())
        dy = max(ymx,0) - min(ymn,0)
        sx = 1.
        sy = 1.
        while dx*sx < 10:
            sx *= 1000
        while dy*sy < 10:
            sy *= 1000
        sy *= -1

        with open(fileName, 'w') as fh:
            # fh.write('<svg viewBox="%f %f %f %f">\n' % (rect.left() * sx,
            #                                             rect.top() * sx,
            #                                             rect.width() * sy,
            #                                             rect.height()*sy))
            fh.write('<svg>\n')
            fh.write('<path fill="none" stroke="#000000" stroke-opacity="0.5" '
                     'stroke-width="1" d="M%f,0 L%f,0"/>\n' % (
                        rect.left() * sx, rect.right() * sx))
            fh.write('<path fill="none" stroke="#000000" stroke-opacity="0.5" '
                     'stroke-width="1" d="M0,%f L0,%f"/>\n' % (
                        rect.top() * sy, rect.bottom() * sy))

            for item in self.curves:
                if isinstance(item, PlotCurveItem):
                    color = fn.colorStr(item.pen.color())
                    opacity = item.pen.color().alpha() / 255.
                    color = color[:6]
                    x, y = item.getData()
                    mask = (x > xRange[0]) * (x < xRange[1])
                    mask[:-1] += mask[1:]
                    m2 = mask.copy()
                    mask[1:] += m2[:-1]
                    x = x[mask]
                    y = y[mask]

                    x *= sx
                    y *= sy

                    # fh.write('<g fill="none" stroke="#%s" '
                    #          'stroke-opacity="1" stroke-width="1">\n' % (
                    #           color, ))
                    fh.write('<path fill="none" stroke="#%s" '
                             'stroke-opacity="%f" stroke-width="1" '
                             'd="M%f,%f ' % (color, opacity, x[0], y[0]))
                    for i in range(1, len(x)):
                        fh.write('L%f,%f ' % (x[i], y[i]))

                    fh.write('"/>')
                    # fh.write("</g>")

            for item in self.dataItems:
                if isinstance(item, ScatterPlotItem):
                    pRect = item.boundingRect()
                    vRect = pRect.intersected(rect)

                    for point in item.points():
                        pos = point.pos()
                        if not rect.contains(pos):
                            continue
                        color = fn.colorStr(point.brush.color())
                        opacity = point.brush.color().alpha() / 255.
                        color = color[:6]
                        x = pos.x() * sx
                        y = pos.y() * sy

                        fh.write('<circle cx="%f" cy="%f" r="1" fill="#%s" '
                                 'stroke="none" fill-opacity="%f"/>\n' % (
                                    x, y, color, opacity))

            fh.write("</svg>\n")

    def writeSvg(self, fileName=None):
        if fileName is None:
            self._chooseFilenameDialog(handler=self.writeSvg)
            return

        fileName = str(fileName)
        PlotItem.lastFileDir = os.path.dirname(fileName)
        
        from ...exporters import SVGExporter
        ex = SVGExporter(self)
        ex.export(fileName)
        
    def writeImage(self, fileName=None):
        if fileName is None:
            self._chooseFilenameDialog(handler=self.writeImage)
            return

        from ...exporters import ImageExporter
        ex = ImageExporter(self)
        ex.export(fileName)
        
    def writeCsv(self, fileName=None):
        if fileName is None:
            self._chooseFilenameDialog(handler=self.writeCsv)
            return

        fileName = str(fileName)
        PlotItem.lastFileDir = os.path.dirname(fileName)
        
        data = [c.getData() for c in self.curves]
        with open(fileName, 'w') as fd:
            i = 0
            while True:
                done = True
                for d in data:
                    if i < len(d[0]):
                        fd.write('%g,%g,' % (d[0][i], d[1][i]))
                        done = False
                    else:
                        fd.write(' , ,')
                fd.write('\n')
                if done:
                    break
                i += 1

    def saveState(self):
        state = self.stateGroup.state()
        state['paramList'] = self.paramList.copy()
        state['view'] = self.vb.getState()
        return state
        
    def restoreState(self, state):
        if 'paramList' in state:
            self.paramList = state['paramList'].copy()
            
        self.stateGroup.setState(state)
        self.updateSpectrumMode()
        self.updateDownsampling()
        self.updateAlpha()
        self.updateDecimation()
        
        if 'powerSpectrumGroup' in state:
            state['fftCheck'] = state['powerSpectrumGroup']
        if 'gridGroup' in state:
            state['xGridCheck'] = state['gridGroup']
            state['yGridCheck'] = state['gridGroup']
            
        self.stateGroup.setState(state)
        self.updateParamList()
        
        if 'view' not in state:
            r = [[float(state['xMinText']), float(state['xMaxText'])], [float(state['yMinText']), float(state['yMaxText'])]]
            state['view'] = {
                'autoRange': [state['xAutoRadio'], state['yAutoRadio']],
                'linkedViews': [state['xLinkCombo'], state['yLinkCombo']],
                'targetRange': r,
                'viewRange': r,
            }
        self.vb.setState(state['view'])

    def widgetGroupInterface(self):
        return (None, PlotItem.saveState, PlotItem.restoreState)
      
    def updateSpectrumMode(self, b=None):
        if b is None:
            b = self.ctrl.fftCheck.isChecked()
        for c in self.curves:
            c.setFftMode(b)
        self.enableAutoRange()
        self.recomputeAverages()
            
    def updateLogMode(self):
        x = self.ctrl.logXCheck.isChecked()
        y = self.ctrl.logYCheck.isChecked()
        for i in self.items:
            if hasattr(i, 'setLogMode'):
                i.setLogMode(x,y)
        self.getAxis('bottom').setLogMode(x)
        self.getAxis('top').setLogMode(x)
        self.getAxis('left').setLogMode(y)
        self.getAxis('right').setLogMode(y)
        self.enableAutoRange()
        self.recomputeAverages()
    
    def updateDerivativeMode(self):
        d = self.ctrl.derivativeCheck.isChecked()
        for i in self.items:
            if hasattr(i, 'setDerivativeMode'):
                i.setDerivativeMode(d)
        self.enableAutoRange()
        self.recomputeAverages()

    def updatePhasemapMode(self):
        d = self.ctrl.phasemapCheck.isChecked()
        for i in self.items:
            if hasattr(i, 'setPhasemapMode'):
                i.setPhasemapMode(d)
        self.enableAutoRange()
        self.recomputeAverages()
        
        
    def setDownsampling(self, ds=None, auto=None, mode=None):
        """Change the default downsampling mode for all PlotDataItems managed by this plot.
        
        =============== =================================================================
        **Arguments:**
        ds              (int) Reduce visible plot samples by this factor, or
                        (bool) To enable/disable downsampling without changing the value.
        auto            (bool) If True, automatically pick *ds* based on visible range
        mode            'subsample': Downsample by taking the first of N samples.
                        This method is fastest and least accurate.
                        'mean': Downsample by taking the mean of N samples.
                        'peak': Downsample by drawing a saw wave that follows the min
                        and max of the original data. This method produces the best
                        visual representation of the data but is slower.
        =============== =================================================================
        """
        if ds is not None:
            if ds is False:
                self.ctrl.downsampleCheck.setChecked(False)
            elif ds is True:
                self.ctrl.downsampleCheck.setChecked(True)
            else:
                self.ctrl.downsampleCheck.setChecked(True)
                self.ctrl.downsampleSpin.setValue(ds)
                
        if auto is not None:
            if auto and ds is not False:
                self.ctrl.downsampleCheck.setChecked(True)
            self.ctrl.autoDownsampleCheck.setChecked(auto)
            
        if mode is not None:
            if mode == 'subsample':
                self.ctrl.subsampleRadio.setChecked(True)
            elif mode == 'mean':
                self.ctrl.meanRadio.setChecked(True)
            elif mode == 'peak':
                self.ctrl.peakRadio.setChecked(True)
            else:
                raise ValueError("mode argument must be 'subsample', 'mean', or 'peak'.")
            
    def updateDownsampling(self):
        ds, auto, method = self.downsampleMode()
        clip = self.ctrl.clipToViewCheck.isChecked()
        for c in self.curves:
            c.setDownsampling(ds, auto, method)
            c.setClipToView(clip)
        self.recomputeAverages()
        
    def downsampleMode(self):
        if self.ctrl.downsampleCheck.isChecked():
            ds = self.ctrl.downsampleSpin.value()
        else:
            ds = 1
            
        auto = self.ctrl.downsampleCheck.isChecked() and self.ctrl.autoDownsampleCheck.isChecked()
            
        if self.ctrl.subsampleRadio.isChecked():
            method = 'subsample' 
        elif self.ctrl.meanRadio.isChecked():
            method = 'mean'
        elif self.ctrl.peakRadio.isChecked():
            method = 'peak'
        
        return ds, auto, method
        
    def setClipToView(self, clip):
        """Set the default clip-to-view mode for all PlotDataItems managed by this plot.
        If *clip* is True, then PlotDataItems will attempt to draw only points within the visible
        range of the ViewBox."""
        self.ctrl.clipToViewCheck.setChecked(clip)
        
    def clipToViewMode(self):
        return self.ctrl.clipToViewCheck.isChecked()

    def updateDecimation(self):
        if self.ctrl.maxTracesCheck.isChecked():
            numCurves = self.ctrl.maxTracesSpin.value()
        else:
            numCurves = -1
            
        curves = self.curves[:]
        split = len(curves) - numCurves
        for curve in curves[split:]:
            if numCurves != -1:
                if self.ctrl.forgetTracesCheck.isChecked():
                    curve.clear()
                    self.removeItem(curves[i])
                else:
                    curve.hide()        
      
    def updateAlpha(self, *args):
        (alpha, auto) = self.alphaState()
        for c in self.curves:
            c.setAlpha(alpha**2, auto)
     
    def alphaState(self):
        enabled = self.ctrl.alphaGroup.isChecked()
        auto = self.ctrl.autoAlphaCheck.isChecked()
        alpha = float(self.ctrl.alphaSlider.value()) / self.ctrl.alphaSlider.maximum()
        if auto:
            alpha = 1.0  ## should be 1/number of overlapping plots
        if not enabled:
            auto = False
            alpha = 1.0
        return (alpha, auto)

    def pointMode(self):
        if self.ctrl.pointsGroup.isChecked():
            if self.ctrl.autoPointsCheck.isChecked():
                mode = None
            else:
                mode = True
        else:
            mode = False
        return mode

    def resizeEvent(self, ev):
        if self.autoBtn is None:  ## already closed down
            return
        btnRect = self.mapRectFromItem(self.autoBtn, self.autoBtn.boundingRect())
        y = self.size().height() - btnRect.height()
        self.autoBtn.setPos(0, y)
    
    def getMenu(self):
        return self.ctrlMenu
    
    def getContextMenus(self, event):
        ## called when another item is displaying its context menu; we get to add extras to the end of the menu.
        if self.menuEnabled():
            return self.ctrlMenu
        else:
            return None
    
    def setMenuEnabled(self, enableMenu=True, enableViewBoxMenu='same'):
        """
        Enable or disable the context menu for this PlotItem.
        By default, the ViewBox's context menu will also be affected.
        (use enableViewBoxMenu=None to leave the ViewBox unchanged)
        """
        self._menuEnabled = enableMenu
        if enableViewBoxMenu is None:
            return
        if enableViewBoxMenu == 'same':
            enableViewBoxMenu = enableMenu
        self.vb.setMenuEnabled(enableViewBoxMenu)
    
    def menuEnabled(self):
        return self._menuEnabled
    
    def hoverEvent(self, ev):
        if ev.enter:
            self.mouseHovering = True
        if ev.exit:
            self.mouseHovering = False
            
        self.updateButtons()

    def getLabel(self, key):
        pass
        
    def _checkScaleKey(self, key):
        if key not in self.axes:
            raise Exception("Scale '%s' not found. Scales are: %s" % (key, str(list(self.axes.keys()))))
        
    def getScale(self, key):
        return self.getAxis(key)
        
    def getAxis(self, name):
        """Return the specified AxisItem. 
        *name* should be 'left', 'bottom', 'top', or 'right'."""
        self._checkScaleKey(name)
        return self.axes[name]['item']
        
    def setLabel(self, axis, text=None, units=None, unitPrefix=None, **args):
        """
        Set the label for an axis. Basic HTML formatting is allowed.
        
        ==============  =================================================================
        **Arguments:**
        axis            must be one of 'left', 'bottom', 'right', or 'top'
        text            text to display along the axis. HTML allowed.
        units           units to display after the title. If units are given,
                        then an SI prefix will be automatically appended
                        and the axis values will be scaled accordingly.
                        (ie, use 'V' instead of 'mV'; 'm' will be added automatically)
        ==============  =================================================================
        """
        self.getAxis(axis).setLabel(text=text, units=units, **args)
        self.showAxis(axis)
        
    def setLabels(self, **kwds):
        """
        Convenience function allowing multiple labels and/or title to be set in one call.
        Keyword arguments can be 'title', 'left', 'bottom', 'right', or 'top'.
        Values may be strings or a tuple of arguments to pass to setLabel.
        """
        for k,v in kwds.items():
            if k == 'title':
                self.setTitle(v)
            else:
                if isinstance(v, basestring):
                    v = (v,)
                self.setLabel(k, *v)
        
    def showLabel(self, axis, show=True):
        """
        Show or hide one of the plot's axis labels (the axis itself will be unaffected).
        axis must be one of 'left', 'bottom', 'right', or 'top'
        """
        self.getScale(axis).showLabel(show)

    def setTitle(self, title=None, **args):
        """
        Set the title of the plot. Basic HTML formatting is allowed.
        If title is None, then the title will be hidden.
        """
        if title is None:
            self.titleLabel.setVisible(False)
            self.layout.setRowFixedHeight(0, 0)
            self.titleLabel.setMaximumHeight(0)
        else:
            self.titleLabel.setMaximumHeight(30)
            self.layout.setRowFixedHeight(0, 30)
            self.titleLabel.setVisible(True)
            self.titleLabel.setText(title, **args)

    def showAxis(self, axis, show=True):
        """
        Show or hide one of the plot's axes.
        axis must be one of 'left', 'bottom', 'right', or 'top'
        """
        s = self.getScale(axis)
        p = self.axes[axis]['pos']
        if show:
            s.show()
        else:
            s.hide()
            
    def hideAxis(self, axis):
        """Hide one of the PlotItem's axes. ('left', 'bottom', 'right', or 'top')"""
        self.showAxis(axis, False)
            
    def showScale(self, *args, **kargs):
        print("Deprecated. use showAxis() instead")
        return self.showAxis(*args, **kargs)
            
    def hideButtons(self):
        """Causes auto-scale button ('A' in lower-left corner) to be hidden for this PlotItem"""
        #self.ctrlBtn.hide()
        self.buttonsHidden = True
        self.updateButtons()
        
    def showButtons(self):
        """Causes auto-scale button ('A' in lower-left corner) to be visible for this PlotItem"""
        #self.ctrlBtn.hide()
        self.buttonsHidden = False
        self.updateButtons()
        
    def updateButtons(self):
        try:
            if self._exportOpts is False and self.mouseHovering and not self.buttonsHidden and not all(self.vb.autoRangeEnabled()):
                self.autoBtn.show()
            else:
                self.autoBtn.hide()
        except RuntimeError:
            pass  # this can happen if the plot has been deleted.
            
    def _plotArray(self, arr, x=None, **kargs):
        if arr.ndim != 1:
            raise Exception("Array must be 1D to plot (shape is %s)" % arr.shape)
        if x is None:
            x = np.arange(arr.shape[0])
        if x.ndim != 1:
            raise Exception("X array must be 1D to plot (shape is %s)" % x.shape)
        c = PlotCurveItem(arr, x=x, **kargs)
        return c
        
    def _plotMetaArray(self, arr, x=None, autoLabel=True, **kargs):
        inf = arr.infoCopy()
        if arr.ndim != 1:
            raise Exception('can only automatically plot 1 dimensional arrays.')
        ## create curve
        try:
            xv = arr.xvals(0)
        except:
            if x is None:
                xv = np.arange(arr.shape[0])
            else:
                xv = x
        c = PlotCurveItem(**kargs)
        c.setData(x=xv, y=arr.view(np.ndarray))
        
        if autoLabel:
            name = arr._info[0].get('name', None)
            units = arr._info[0].get('units', None)
            self.setLabel('bottom', text=name, units=units)
            
            name = arr._info[1].get('name', None)
            units = arr._info[1].get('units', None)
            self.setLabel('left', text=name, units=units)
            
        return c
      
    def setExportMode(self, export, opts=None):
        GraphicsWidget.setExportMode(self, export, opts)
        self.updateButtons()
    
    def _chooseFilenameDialog(self, handler):
        self.fileDialog = FileDialog()
        if PlotItem.lastFileDir is not None:
            self.fileDialog.setDirectory(PlotItem.lastFileDir)
        self.fileDialog.setFileMode(QtGui.QFileDialog.AnyFile)
        self.fileDialog.setAcceptMode(QtGui.QFileDialog.AcceptSave)
        self.fileDialog.show()
        self.fileDialog.fileSelected.connect(handler)
