text: from ..Qt import QtCore, QtGui, QtWidgets
  from ..python2_3 import asUnicode
  from .Parameter import Parameter, registerParameterType
  from .ParameterItem import ParameterItem
  from ..widgets.SpinBox import SpinBox
  from ..widgets.ColorButton import ColorButton
  #from ..widgets.GradientWidget import GradientWidget ## creates import loop
  from .. import pixmaps as pixmaps
  from .. import functions as fn
  import os
  from ..pgcollections import OrderedDict
  
  class WidgetParameterItem(ParameterItem):
      """
      ParameterTree item with:
      
      * label in second column for displaying value
      * simple widget for editing value (displayed instead of label when item is selected)
      * button that resets value to default
      
      ==========================  =============================================================
      **Registered Types:**
      int                         Displays a :class:`SpinBox <pyqtgraph.SpinBox>` in integer
                                  mode.
      float                       Displays a :class:`SpinBox <pyqtgraph.SpinBox>`.
      bool                        Displays a QCheckBox
      str                         Displays a QLineEdit
      color                       Displays a :class:`ColorButton <pyqtgraph.ColorButton>`
      colormap                    Displays a :class:`GradientWidget <pyqtgraph.GradientWidget>`
      ==========================  =============================================================
      
      This class can be subclassed by overriding makeWidget() to provide a custom widget.
      """
      def __init__(self, param, depth):
          ParameterItem.__init__(self, param, depth)
          
          self.hideWidget = True  ## hide edit widget, replace with label when not selected
                                  ## set this to False to keep the editor widget always visible
          
          
          ## build widget into column 1 with a display label and default button.
          w = self.makeWidget()  
          self.widget = w
          self.eventProxy = EventProxy(w, self.widgetEventFilter)
          
          opts = self.param.opts
          if 'tip' in opts:
              w.setToolTip(opts['tip'])
          
          self.defaultBtn = QtWidgets.QPushButton()
          self.defaultBtn.setFixedWidth(20)
          self.defaultBtn.setFixedHeight(20)
          modDir = os.path.dirname(__file__)
          self.defaultBtn.setIcon(QtGui.QIcon(pixmaps.getPixmap('default')))
          self.defaultBtn.clicked.connect(self.defaultClicked)
          
          self.displayLabel = QtWidgets.QLabel()
          
          layout = QtWidgets.QHBoxLayout()
          layout.setContentsMargins(0, 0, 0, 0)
          layout.setSpacing(2)
          layout.addWidget(w)
          layout.addWidget(self.displayLabel)
          layout.addWidget(self.defaultBtn)
          self.layoutWidget = QtWidgets.QWidget()
          self.layoutWidget.setLayout(layout)
          
          if w.sigChanged is not None:
              w.sigChanged.connect(self.widgetValueChanged)
              
          if hasattr(w, 'sigChanging'):
              w.sigChanging.connect(self.widgetValueChanging)
              
          ## update value shown in widget. 
          if opts.get('value', None) is not None:
              self.valueChanged(self, opts['value'], force=True)
          else:
              ## no starting value was given; use whatever the widget has
              self.widgetValueChanged()
  
          self.updateDefaultBtn()
  
      def makeWidget(self):
          """
          Return a single widget that should be placed in the second tree column.
          The widget must be given three attributes:
          
          ==========  ============================================================
          sigChanged  a signal that is emitted when the widget's value is changed
          value       a function that returns the value
          setValue    a function that sets the value
          ==========  ============================================================
              
          This is a good function to override in subclasses.
          """
          opts = self.param.opts
          t = opts['type']
          if t == 'int':
              defs = {
                  'value': 0, 'min': None, 'max': None, 'int': True, 
                  'step': 1.0, 'minStep': 1.0, 'dec': False, 
                  'siPrefix': False, 'suffix': ''
              } 
              defs.update(opts)
              if 'limits' in opts:
                  defs['bounds'] = opts['limits']
              w = SpinBox()
              w.setOpts(**defs)
              w.sigChanged = w.sigValueChanged
              w.sigChanging = w.sigValueChanging
          elif t == 'float':
              defs = {
                  'value': 0, 'min': None, 'max': None, 
                  'step': 1.0, 'dec': False, 
                  'siPrefix': False, 'suffix': ''
              }
              defs.update(opts)
              if 'limits' in opts:
                  defs['bounds'] = opts['limits']
              w = SpinBox()
              w.setOpts(**defs)
              w.sigChanged = w.sigValueChanged
              w.sigChanging = w.sigValueChanging
          elif t == 'bool':
              w = QtWidgets.QCheckBox()
              w.sigChanged = w.toggled
              w.value = w.isChecked
              w.setValue = w.setChecked
              w.setEnabled(not opts.get('readonly', False))
              self.hideWidget = False
          elif t == 'str':
              w = QtWidgets.QLineEdit()
              w.sigChanged = w.editingFinished
              w.value = lambda: asUnicode(w.text())
              w.setValue = lambda v: w.setText(asUnicode(v))
              w.sigChanging = w.textChanged
          elif t == 'color':
              w = ColorButton()
              w.sigChanged = w.sigColorChanged
              w.sigChanging = w.sigColorChanging
              w.value = w.color
              w.setValue = w.setColor
              self.hideWidget = False
              w.setFlat(True)
              w.setEnabled(not opts.get('readonly', False))            
          elif t == 'colormap':
              from ..widgets.GradientWidget import GradientWidget ## need this here to avoid import loop
              w = GradientWidget(orientation='bottom')
              w.sigChanged = w.sigGradientChangeFinished
              w.sigChanging = w.sigGradientChanged
              w.value = w.colorMap
              w.setValue = w.setColorMap
              self.hideWidget = False
          else:
              raise Exception("Unknown type '%s'" % asUnicode(t))
          return w
          
      def widgetEventFilter(self, obj, ev):
          ## filter widget's events
          ## catch TAB to change focus
          ## catch focusOut to hide editor
          if ev.type() == ev.KeyPress:
              if ev.key() == QtCore.Qt.Key_Tab:
                  self.focusNext(forward=True)
                  return True ## don't let anyone else see this event
              elif ev.key() == QtCore.Qt.Key_Backtab:
                  self.focusNext(forward=False)
                  return True ## don't let anyone else see this event
              
          #elif ev.type() == ev.FocusOut:
              #self.hideEditor()
          return False
          
      def setFocus(self):
          self.showEditor()
          
      def isFocusable(self):
          return self.param.writable()        
          
      def valueChanged(self, param, val, force=False):
          ## called when the parameter's value has changed
          ParameterItem.valueChanged(self, param, val)
          self.widget.sigChanged.disconnect(self.widgetValueChanged)
          try:
              if force or val != self.widget.value():
                  self.widget.setValue(val)
              self.updateDisplayLabel(val)  ## always make sure label is updated, even if values match!
          finally:
              self.widget.sigChanged.connect(self.widgetValueChanged)
          self.updateDefaultBtn()
          
      def updateDefaultBtn(self):
          ## enable/disable default btn 
          self.defaultBtn.setEnabled(not self.param.valueIsDefault() and self.param.writable())        
          
          # hide / show
          self.defaultBtn.setVisible(not self.param.readonly())
  
      def updateDisplayLabel(self, value=None):
          """Update the display label to reflect the value of the parameter."""
          if value is None:
              value = self.param.value()
          opts = self.param.opts
          if isinstance(self.widget, QtWidgets.QAbstractSpinBox):
              text = asUnicode(self.widget.lineEdit().text())
          elif isinstance(self.widget, QtWidgets.QComboBox):
              text = self.widget.currentText()
          else:
              text = asUnicode(value)
          self.displayLabel.setText(text)
  
      def widgetValueChanged(self):
          ## called when the widget's value has been changed by the user
          val = self.widget.value()
          newVal = self.param.setValue(val)
  
      def widgetValueChanging(self, *args):
          """
          Called when the widget's value is changing, but not finalized.
          For example: editing text before pressing enter or changing focus.
          """
          # This is a bit sketchy: assume the last argument of each signal is
          # the value..
          self.param.sigValueChanging.emit(self.param, args[-1])
          
      def selected(self, sel):
          """Called when this item has been selected (sel=True) OR deselected (sel=False)"""
          ParameterItem.selected(self, sel)
          
          if self.widget is None:
              return
          if sel and self.param.writable():
              self.showEditor()
          elif self.hideWidget:
              self.hideEditor()
  
      def showEditor(self):
          self.widget.show()
          self.displayLabel.hide()
          self.widget.setFocus(QtCore.Qt.OtherFocusReason)
          if isinstance(self.widget, SpinBox):
              self.widget.selectNumber()  # select the numerical portion of the text for quick editing
  
      def hideEditor(self):
          self.widget.hide()
          self.displayLabel.show()
  
      def limitsChanged(self, param, limits):
          """Called when the parameter's limits have changed"""
          ParameterItem.limitsChanged(self, param, limits)
          
          t = self.param.opts['type']
          if t == 'int' or t == 'float':
              self.widget.setOpts(bounds=limits)
          else:
              return  ## don't know what to do with any other types..
  
      def defaultChanged(self, param, value):
          self.updateDefaultBtn()
  
      def treeWidgetChanged(self):
          """Called when this item is added or removed from a tree."""
          ParameterItem.treeWidgetChanged(self)
          
          ## add all widgets for this item into the tree
          if self.widget is not None:
              tree = self.treeWidget()
              if tree is None:
                  return
              tree.setItemWidget(self, 1, self.layoutWidget)
              self.displayLabel.hide()
              self.selected(False)            
  
      def defaultClicked(self):
          self.param.setToDefault()
  
      def optsChanged(self, param, opts):
          """Called when any options are changed that are not
          name, value, default, or limits"""
          #print "opts changed:", opts
          ParameterItem.optsChanged(self, param, opts)
          
          if 'readonly' in opts:
              self.updateDefaultBtn()
              if isinstance(self.widget, (QtWidgets.QCheckBox,ColorButton)):
                  self.widget.setEnabled(not opts['readonly'])
          
          ## If widget is a SpinBox, pass options straight through
          if isinstance(self.widget, SpinBox):
              if 'units' in opts and 'suffix' not in opts:
                  opts['suffix'] = opts['units']
              self.widget.setOpts(**opts)
              self.updateDisplayLabel()
          
          
          
              
  class EventProxy(QtCore.QObject):
      def __init__(self, qobj, callback):
          QtCore.QObject.__init__(self)
          self.callback = callback
          qobj.installEventFilter(self)
          
      def eventFilter(self, obj, ev):
          return self.callback(obj, ev)
  
          
  
  
  class SimpleParameter(Parameter):
      itemClass = WidgetParameterItem
      
      def __init__(self, *args, **kargs):
          Parameter.__init__(self, *args, **kargs)
          
          ## override a few methods for color parameters
          if self.opts['type'] == 'color':
              self.value = self.colorValue
              self.saveState = self.saveColorState
      
      def colorValue(self):
          return fn.mkColor(Parameter.value(self))
      
      def saveColorState(self, *args, **kwds):
          state = Parameter.saveState(self, *args, **kwds)
          state['value'] = fn.colorTuple(self.value())
          return state
          
      
  registerParameterType('int', SimpleParameter, override=True)
  registerParameterType('float', SimpleParameter, override=True)
  registerParameterType('bool', SimpleParameter, override=True)
  registerParameterType('str', SimpleParameter, override=True)
  registerParameterType('color', SimpleParameter, override=True)
  registerParameterType('colormap', SimpleParameter, override=True)
  
  
  
  
  class GroupParameterItem(ParameterItem):
      """
      Group parameters are used mainly as a generic parent item that holds (and groups!) a set
      of child parameters. It also provides a simple mechanism for displaying a button or combo
      that can be used to add new parameters to the group.
      """
      def __init__(self, param, depth):
          ParameterItem.__init__(self, param, depth)
          self.updateDepth(depth) 
                  
          self.addItem = None
          if 'addText' in param.opts:
              addText = param.opts['addText']
              if 'addList' in param.opts:
                  self.addWidget = QtWidgets.QComboBox()
                  self.addWidget.setSizeAdjustPolicy(QtWidgets.QComboBox.AdjustToContents)
                  self.updateAddList()
                  self.addWidget.currentIndexChanged.connect(self.addChanged)
              else:
                  self.addWidget = QtWidgets.QPushButton(addText)
                  self.addWidget.clicked.connect(self.addClicked)
              w = QtWidgets.QWidget()
              l = QtWidgets.QHBoxLayout()
              l.setContentsMargins(0,0,0,0)
              w.setLayout(l)
              l.addWidget(self.addWidget)
              l.addStretch()
              #l.addItem(QtGui.QSpacerItem(200, 10, QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Minimum))
              self.addWidgetBox = w
              self.addItem = QtWidgets.QTreeWidgetItem([])
              self.addItem.setFlags(QtCore.Qt.ItemIsEnabled)
              ParameterItem.addChild(self, self.addItem)
              
      def updateDepth(self, depth):
          ## Change item's appearance based on its depth in the tree
          ## This allows highest-level groups to be displayed more prominently.
          if depth == 0:
              for c in [0,1]:
                  self.setBackground(c, QtGui.QBrush(QtGui.QColor(100,100,100)))
                  self.setForeground(c, QtGui.QBrush(QtGui.QColor(220,220,255)))
                  font = self.font(c)
                  font.setBold(True)
                  font.setPointSize(font.pointSize()+1)
                  self.setFont(c, font)
                  self.setSizeHint(0, QtCore.QSize(0, 25))
          else:
              for c in [0,1]:
                  self.setBackground(c, QtGui.QBrush(QtGui.QColor(220,220,220)))
                  font = self.font(c)
                  font.setBold(True)
                  #font.setPointSize(font.pointSize()+1)
                  self.setFont(c, font)
                  self.setSizeHint(0, QtCore.QSize(0, 20))
      
      def addClicked(self):
          """Called when "add new" button is clicked
          The parameter MUST have an 'addNew' method defined.
          """
          self.param.addNew()
  
      def addChanged(self):
          """Called when "add new" combo is changed
          The parameter MUST have an 'addNew' method defined.
          """
          if self.addWidget.currentIndex() == 0:
              return
          typ = asUnicode(self.addWidget.currentText())
          self.param.addNew(typ)
          self.addWidget.setCurrentIndex(0)
  
      def treeWidgetChanged(self):
          ParameterItem.treeWidgetChanged(self)
          self.treeWidget().setFirstItemColumnSpanned(self, True)
          if self.addItem is not None:
              self.treeWidget().setItemWidget(self.addItem, 0, self.addWidgetBox)
              self.treeWidget().setFirstItemColumnSpanned(self.addItem, True)
          
      def addChild(self, child):  ## make sure added childs are actually inserted before add btn
          if self.addItem is not None:
              ParameterItem.insertChild(self, self.childCount()-1, child)
          else:
              ParameterItem.addChild(self, child)
              
      def optsChanged(self, param, changed):
          if 'addList' in changed:
              self.updateAddList()
                  
      def updateAddList(self):
          self.addWidget.blockSignals(True)
          try:
              self.addWidget.clear()
              self.addWidget.addItem(self.param.opts['addText'])
              for t in self.param.opts['addList']:
                  self.addWidget.addItem(t)
          finally:
              self.addWidget.blockSignals(False)
              
  class GroupParameter(Parameter):
      """
      Group parameters are used mainly as a generic parent item that holds (and groups!) a set
      of child parameters. 
      
      It also provides a simple mechanism for displaying a button or combo
      that can be used to add new parameters to the group. To enable this, the group 
      must be initialized with the 'addText' option (the text will be displayed on
      a button which, when clicked, will cause addNew() to be called). If the 'addList'
      option is specified as well, then a dropdown-list of addable items will be displayed
      instead of a button.
      """
      itemClass = GroupParameterItem
  
      def addNew(self, typ=None):
          """
          This method is called when the user has requested to add a new item to the group.
          """
          raise Exception("Must override this function in subclass.")
      
      def setAddList(self, vals):
          """Change the list of options available for the user to add to the group."""
          self.setOpts(addList=vals)
  
      
  
  registerParameterType('group', GroupParameter, override=True)
  
  
  
  
  
  class ListParameterItem(WidgetParameterItem):
      """
      WidgetParameterItem subclass providing comboBox that lets the user select from a list of options.
      
      """
      def __init__(self, param, depth):
          self.targetValue = None
          WidgetParameterItem.__init__(self, param, depth)
          
          
      def makeWidget(self):
          opts = self.param.opts
          t = opts['type']
          w = QtWidgets.QComboBox()
          w.setMaximumHeight(20)  ## set to match height of spin box and line edit
          w.sigChanged = w.currentIndexChanged
          w.value = self.value
          w.setValue = self.setValue
          self.widget = w  ## needs to be set before limits are changed
          self.limitsChanged(self.param, self.param.opts['limits'])
          if len(self.forward) > 0:
              self.setValue(self.param.value())
          return w
          
      def value(self):
          key = asUnicode(self.widget.currentText())
          
          return self.forward.get(key, None)
              
      def setValue(self, val):
          self.targetValue = val
          if val not in self.reverse[0]:
              self.widget.setCurrentIndex(0)
          else:
              key = self.reverse[1][self.reverse[0].index(val)]
              ind = self.widget.findText(key)
              self.widget.setCurrentIndex(ind)
  
      def limitsChanged(self, param, limits):
          # set up forward / reverse mappings for name:value
          
          if len(limits) == 0:
              limits = ['']  ## Can never have an empty list--there is always at least a singhe blank item.
          
          self.forward, self.reverse = ListParameter.mapping(limits)
          try:
              self.widget.blockSignals(True)
              val = self.targetValue  #asUnicode(self.widget.currentText())
              
              self.widget.clear()
              for k in self.forward:
                  self.widget.addItem(k)
                  if k == val:
                      self.widget.setCurrentIndex(self.widget.count()-1)
                      self.updateDisplayLabel()
          finally:
              self.widget.blockSignals(False)
              
  
  
  class ListParameter(Parameter):
      itemClass = ListParameterItem
  
      def __init__(self, **opts):
          self.forward = OrderedDict()  ## {name: value, ...}
          self.reverse = ([], [])       ## ([value, ...], [name, ...])
          
          ## Parameter uses 'limits' option to define the set of allowed values
          if 'values' in opts:
              opts['limits'] = opts['values']
          if opts.get('limits', None) is None:
              opts['limits'] = []
          Parameter.__init__(self, **opts)
          self.setLimits(opts['limits'])
          
      def setLimits(self, limits):
          self.forward, self.reverse = self.mapping(limits)
          
          Parameter.setLimits(self, limits)
          if len(self.reverse[0]) > 0 and self.value() not in self.reverse[0]:
              self.setValue(self.reverse[0][0])
              
      #def addItem(self, name, value=None):
          #if name in self.forward:
              #raise Exception("Name '%s' is already in use for this parameter" % name)
          #limits = self.opts['limits']
          #if isinstance(limits, dict):
              #limits = limits.copy()
              #limits[name] = value
              #self.setLimits(limits)
          #else:
              #if value is not None:
                  #raise Exception  ## raise exception or convert to dict?
              #limits = limits[:]
              #limits.append(name)
          ## what if limits == None?
              
      @staticmethod
      def mapping(limits):
          ## Return forward and reverse mapping objects given a limit specification
          forward = OrderedDict()  ## {name: value, ...}
          reverse = ([], [])       ## ([value, ...], [name, ...])
          if isinstance(limits, dict):
              for k, v in limits.items():
                  forward[k] = v
                  reverse[0].append(v)
                  reverse[1].append(k)
          else:
              for v in limits:
                  n = asUnicode(v)
                  forward[n] = v
                  reverse[0].append(v)
                  reverse[1].append(n)
          return forward, reverse
  
  registerParameterType('list', ListParameter, override=True)
  
  
  
  class ActionParameterItem(ParameterItem):
      def __init__(self, param, depth):
          ParameterItem.__init__(self, param, depth)
          self.layoutWidget = QtWidgets.QWidget()
          self.layout = QtWidgets.QHBoxLayout()
          self.layoutWidget.setLayout(self.layout)
          self.button = QtWidgets.QPushButton(param.name())
          #self.layout.addSpacing(100)
          self.layout.addWidget(self.button)
          self.layout.addStretch()
          self.button.clicked.connect(self.buttonClicked)
          param.sigNameChanged.connect(self.paramRenamed)
          self.setText(0, '')
          
      def treeWidgetChanged(self):
          ParameterItem.treeWidgetChanged(self)
          tree = self.treeWidget()
          if tree is None:
              return
          
          tree.setFirstItemColumnSpanned(self, True)
          tree.setItemWidget(self, 0, self.layoutWidget)
          
      def paramRenamed(self, param, name):
          self.button.setText(name)
          
      def buttonClicked(self):
          self.param.activate()
          
  class ActionParameter(Parameter):
      """Used for displaying a button within the tree."""
      itemClass = ActionParameterItem
      sigActivated = QtCore.Signal(object)
      
      def activate(self):
          self.sigActivated.emit(self)
          self.emitStateChanged('activated', None)
          
  registerParameterType('action', ActionParameter, override=True)
  
  
  
  class TextParameterItem(WidgetParameterItem):
      def __init__(self, param, depth):
          WidgetParameterItem.__init__(self, param, depth)
          self.hideWidget = False
          self.subItem = QtWidgets.QTreeWidgetItem()
          self.addChild(self.subItem)
  
      def treeWidgetChanged(self):
          ## TODO: fix so that superclass method can be called
          ## (WidgetParameter should just natively support this style)
          #WidgetParameterItem.treeWidgetChanged(self)
          self.treeWidget().setFirstItemColumnSpanned(self.subItem, True)
          self.treeWidget().setItemWidget(self.subItem, 0, self.textBox)
          
          # for now, these are copied from ParameterItem.treeWidgetChanged
          self.setHidden(not self.param.opts.get('visible', True))
          self.setExpanded(self.param.opts.get('expanded', True))
          
      def makeWidget(self):
          self.textBox = QtWidgets.QTextEdit()
          self.textBox.setMaximumHeight(100)
          self.textBox.setReadOnly(self.param.opts.get('readonly', False))
          self.textBox.value = lambda: str(self.textBox.toPlainText())
          self.textBox.setValue = self.textBox.setPlainText
          self.textBox.sigChanged = self.textBox.textChanged
          return self.textBox
          
  class TextParameter(Parameter):
      """Editable string; displayed as large text box in the tree."""
      itemClass = TextParameterItem
  
      
      
  registerParameterType('text', TextParameter, override=True)
  