text: ##########################################################################
  #
  #  Copyright (c) 2008, Image Engine Design Inc. All rights reserved.
  #
  #  Redistribution and use in source and binary forms, with or without
  #  modification, are permitted provided that the following conditions are
  #  met:
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  #       notice, this list of conditions and the following disclaimer.
  #
  #     * Redistributions in binary form must reproduce the above copyright
  #       notice, this list of conditions and the following disclaimer in the
  #       documentation and/or other materials provided with the distribution.
  #
  #     * Neither the name of Image Engine Design nor the names of any
  #       other contributors to this software may be used to endorse or
  #       promote products derived from this software without specific prior
  #       written permission.
  #
  #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  #  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  #  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  #  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  #  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  #  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  #  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  #  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  #  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  #  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  #  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  #
  ##########################################################################
  
  import IECoreMaya
  
  import maya.cmds
  import traceback
  
  ## This class creates a window holding an instance of IECore.Op, presenting a ui
  # for the modification of it's parameters. The user can then execute the op interactively.
  ## \todo We need to close this window if the node is deleted - for instance when the user makes a fresh scene.
  class OpWindow( IECoreMaya.UIElement ) :
  
  	def __init__( self, op ) :
  
  		window = maya.cmds.window( title="Op Settings" )
  
  		IECoreMaya.UIElement.__init__( self, window )
  
  		form = maya.cmds.formLayout()
  
  		infoRow = maya.cmds.rowLayout()
  		maya.cmds.text( label = op.typeName(), annotation = op.description, font = "boldLabelFont" )
  
  		maya.cmds.setParent( form )
  
  		scrollLayout = maya.cmds.scrollLayout( horizontalScrollBarThickness=0 )
  		column = maya.cmds.columnLayout()
  		maya.cmds.separator( parent=column, style="none" )
  		maya.cmds.separator( parent=column, style="none" )
  
  		maya.cmds.setParent( form )
  
  		cancelButton = maya.cmds.button( label="Cancel", command="import maya.cmds; maya.cmds.deleteUI( \"%s\" )" % window )
  		resetButton = maya.cmds.button( label="Reset", command=self._createCallback( self.__revertPressed ) )
  		goButton = maya.cmds.button( label="Go!", command=self._createCallback( self.__goPressed ) )
  
  		self.__fnTPH = IECoreMaya.FnTransientParameterisedHolderNode.create( column, op )
  
  		maya.cmds.setParent( form )
  
  		maya.cmds.formLayout(
  			form,
  			edit = True,
  			attachForm = [
  				( infoRow, "top", 5 ),
  				( infoRow, "left", 5 ),
  				( infoRow, "right", 5 ),
  				( scrollLayout, "left", 5 ),
  				( scrollLayout, "right", 5 ),
  				( cancelButton, "right", 5 ),
  				( goButton, "left", 5 ),
  				( cancelButton, "bottom", 5 ),
  				( resetButton, "bottom", 5 ),
  				( goButton, "bottom", 5 ),
  			],
  			attachPosition = [
  				( cancelButton, "left", 5, 66 ),
  				( goButton, "right", 5, 33 ),
  			],
  			attachControl = [
  				( scrollLayout, "top", 5, infoRow ),
  				( scrollLayout, "bottom", 5, cancelButton ),
  				( resetButton, "left", 5, goButton ),
  				( resetButton, "right", 5, cancelButton ),
  			],
  			attachNone = [
  				( cancelButton, "top" ),
  				( resetButton, "top" ),
  				( goButton, "top" ),
  			]
  		)
  
  		maya.cmds.showWindow( window )
  
  	def __revertPressed( self ) :
  
  		op = self.__fnTPH.getParameterised()[0]
  		op.parameters().setValue( op.parameters().defaultValue )
  		self.__fnTPH.setNodeValues()
  
  	def __goPressed( self ) :
  
  		self.__fnTPH.setParameterisedValues()
  		op = self.__fnTPH.getParameterised()[0]
  
  		valid = op.parameters().valueValid()
  		if not valid[0] :
  			maya.cmds.confirmDialog(
  				title="Parameter Error",
  				message=valid[1], button="OK",
  				defaultButton="OK",
  				parent=self._topLevelUI()
  			)
  			return
  
  		result = None
  		try :
  			result = op()
  		except Exception, e :
  			buttonPressed = maya.cmds.confirmDialog(
  				title="Execution Error",
  				message="Error : " + e.message,
  				button=( "Print Details", "OK" ),
  				defaultButton="OK",
  				parent=self._topLevelUI()
  			)
  			if buttonPressed=="Print Details" :
  				traceback.print_exc()
  
  		if result is not None :
  			maya.cmds.deleteUI( self._topLevelUI() )
  