import sys
from PySide.QtCore import *
from PySide.QtGui import *

class TestFrame( QFrame ):
    def __init__( self, parent=None ):
        super( TestFrame, self ).__init__( parent )
        self.setFrameStyle( QFrame.StyledPanel )
        self.setSizePolicy( parent.sizePolicy() ) # THIS DOESN'T SEEM TO HAVE ANY EFFECT

class SliderWidget( QWidget ):
    def __init__( self ):
        super( SliderWidget, self ).__init__()
        self.buildUI()

    def buildUI( self ):
        self.setLayout( QGridLayout() )

        # ANIMATION GROUP FOR TOP AND BOTTOM FRAMES
        self.animGroup = QParallelAnimationGroup()

        # CREATE WIDGETS
        self.frameCentre = TestFrame( self )
        self.frameTop = TestFrame( self.frameCentre )
        self.frameBottom = TestFrame( self.frameCentre )
        self.btn = QPushButton( 'GO' )

        # TOOLTIPS
        self.frameTop.setToolTip( 'frame top' )
        self.frameCentre.setToolTip( 'frame centre' )
        self.frameBottom.setToolTip( 'frame bottom' )

        # SLIDE IN TOP AND BOTTOM FRAMES
        self.btn.clicked.connect( self.moveWidgets )

        # RESIZE AND REPO TOP AND BOTTOM FRAMES
        # THIS IS WHERE I HAVE TROUBLE TO SET THE RIGHT SIZE AND POSITION
        # I'VE SET ABSOLUTE POSITION AND SCALE JUST TO ILLUSTRATE WHAT I'M AFTER.
        # THIS REALLY NEEDS TO BE LINKED TO THE PARENT SO THE TOP AND BOTOM FRAMES ARE ALWAYS THE SAME WIDTH
        # AND HAVE THE SAME SIZE POLICY AS THE MIDDLE FRAME
        self.frameTop.setGeometry( 0, 0, 800, 100 )
        self.frameBottom.setGeometry( 0, 600, 800, 100 )

        # HIDE TOP AND BOTTOM AT FIRST - DEACTIVATE FOR DEBUGGING
        #self.frameTop.hide()
        #self.frameBottom.hide()

        # ADD CENTRETO LAYOUT
        self.layout().addWidget( self.frameCentre )
        self.layout().addWidget( self.btn )


    def moveWidgets( self ):
        '''trigger animations'''
        self.slideInWidget( self.frameTop, 'topDown' )
        self.slideInWidget( self.frameBottom, 'bottomUp')
        self.animGroup.start()

    def slideInWidget( self, widget, direction ):
        '''assign animation to frames'''
        assert direction in ( 'topDown', 'bottomUp' )
        # DEFINE START AND END POSITION - THIS IS WHERE I HAVE TROUBLE SETTING THE RIGHT POSITION
        if direction == 'topDown':
            start = -1000
            end = 0
        elif direction == 'bottomUp':
            start = 900
            end = 600

        # START ANIMATION
        widget.show()
        slideInAnim = self.slideAnimation( widget, start, end )
        self.animGroup.addAnimation( slideInAnim )

    def slideAnimation( self, widget, start, end ):
        '''Define sliding animation'''
        slideAnimation = QPropertyAnimation( widget, 'pos' )
        slideAnimation.setDuration( 1000 )
        slideAnimation.setStartValue( QPoint( widget.pos().x(), start ) )
        slideAnimation.setEndValue( QPoint( widget.pos().x(), end ) )
        slideAnimation.setEasingCurve( QEasingCurve.OutCubic )
        return slideAnimation

if __name__ == "__main__":

    app = QApplication(sys.argv)
    sw = SliderWidget()

    sw.resize( 800, 750 )
    sw.show()

    sys.exit(app.exec_())