borderlayout.py

#!/usr/bin/env python

#############################################################################
##
## Copyright (C) 2004-2005 Trolltech AS. All rights reserved.
##
## This file is part of the example classes of the Qt Toolkit.
##
## This file may be used under the terms of the GNU General Public
## License version 2.0 as published by the Free Software Foundation
## and appearing in the file LICENSE.GPL included in the packaging of
## this file.  Please review the following information to ensure GNU
## General Public Licensing requirements will be met:
## http://www.trolltech.com/products/qt/opensource.html
##
## If you are unsure which license is appropriate for your use, please
## review the following information:
## http://www.trolltech.com/products/qt/licensing.html or contact the
## sales department at sales@trolltech.com.
##
## This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
## WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
##
#############################################################################

import sys
from PyQt4 import QtCore, QtGui


class ItemWrapper( object ):
    def __init__( self, i, p ):
        self.item = i
        self.position = p


class BorderLayout( QtGui.QLayout ):
    West, North, South, East, Center = range( 5 )
    MinimumSize, SizeHint = range( 2 )

    def __init__( self, parent = None, margin = 0, spacing = -1 ):
        QtGui.QLayout.__init__( self, parent )

        self.setMargin( margin )
        self.setSpacing( spacing )
        self.list = []

    def __del__( self ):
        l = self.takeAt( 0 )
        while l:
            l = self.takeAt( 0 )

    def addItem( self, item ):
        self.add( item, BorderLayout.West )

    def addWidget( self, widget, position ):
        self.add( QtGui.QWidgetItem( widget ), position )

    def expandingDirections( self ):
        return QtCore.Qt.Horizontal | QtCore.Qt.Vertical

    def hasHeightForWidth( self ):
        return False

    def count( self ):
        return len( self.list )

    def itemAt( self, index ):
        if index < len( self.list ):
            return self.list[index].item

        return None

    def minimumSize( self ):
        return self.calculateSize( BorderLayout.MinimumSize )

    def setGeometry( self, rect ):
        center = 0
        eastWidth = 0
        westWidth = 0
        northHeight = 0
        southHeight = 0
        centerHeight = 0

        QtGui.QLayout.setGeometry( self, rect )

        for wrapper in self.list:
            item = wrapper.item
            position = wrapper.position

            if position == BorderLayout.North:
                item.setGeometry( QtCore.QRect( rect.x(), northHeight, rect.width(), item.sizeHint().height() ) )

                northHeight += item.geometry().height() + self.spacing()
            elif position == BorderLayout.South:
                item.setGeometry( QtCore.QRect( item.geometry().x(), item.geometry().y(), rect.width(), item.sizeHint().height() ) )

                southHeight += item.geometry().height() + self.spacing()

                item.setGeometry( QtCore.QRect( rect.x(), rect.y() + rect.height() - southHeight + self.spacing(), item.geometry().width(), item.geometry().height() ) )
            elif position == BorderLayout.Center:
                center = wrapper

        centerHeight = rect.height() - northHeight - southHeight

        for wrapper in self.list:
            item = wrapper.item
            position = wrapper.position

            if position == BorderLayout.West:
                item.setGeometry( QtCore.QRect( rect.x() + westWidth, northHeight, item.sizeHint().width(), centerHeight ) )

                westWidth += item.geometry().width() + self.spacing()
            elif position == BorderLayout.East:
                item.setGeometry( QtCore.QRect( item.geometry().x(), item.geometry().y(), item.sizeHint().width(), centerHeight ) )

                eastWidth += item.geometry().width() + self.spacing()

                item.setGeometry( QtCore.QRect( rect.x() + rect.width() - eastWidth + self.spacing(), northHeight, item.geometry().width(), item.geometry().height() ) )

        if center:
            center.item.setGeometry( QtCore.QRect( westWidth, northHeight, rect.width() - eastWidth - westWidth, centerHeight ) )

    def sizeHint( self ):
        return self.calculateSize( BorderLayout.SizeHint )

    def takeAt( self, index ):
        if index >= 0 and index < len( self.list ):
            layoutStruct = self.list.pop( index )
            return layoutStruct.item

        return None

    def add( self, item, position ):
        self.list.append( ItemWrapper( item, position ) )

    def calculateSize( self, sizeType ):
        totalSize = QtCore.QSize()

        for wrapper in self.list:
            position = wrapper.position
            itemSize = QtCore.QSize()

            if sizeType == BorderLayout.MinimumSize:
                itemSize = wrapper.item.minimumSize()
            else: # sizeType == BorderLayout.SizeHint
                itemSize = wrapper.item.sizeHint()

            if position == BorderLayout.North or position == BorderLayout.South or position == BorderLayout.Center:
                totalSize.setHeight( totalSize.height() + itemSize.height() )

            if position == BorderLayout.West or position == BorderLayout.East or position == BorderLayout.Center:
                totalSize.setWidth( totalSize.width() + itemSize.width() )

        return totalSize


class Window( QtGui.QWidget ):
    def __init__( self, parent = None ):
        QtGui.QWidget.__init__( self, parent )

        centralWidget = QtGui.QTextBrowser()
        centralWidget.setPlainText( self.tr( "Central widget" ) )

        layout = BorderLayout()
        layout.addWidget( centralWidget, BorderLayout.Center )

        # Qt takes ownership of the widgets in the layout when setLayout() is
        # called.  Therefore we keep a local reference to each label to prevent
        # it being garbage collected until the call to setLayout().
        label_n = self.createLabel( "North" )
        layout.addWidget( label_n, BorderLayout.North )

        label_w = self.createLabel( "West" )
        layout.addWidget( label_w, BorderLayout.West )

        label_e1 = self.createLabel( "East 1" )
        layout.addWidget( label_e1, BorderLayout.East )

        label_e2 = self.createLabel( "East 2" )
        layout.addWidget( label_e2, BorderLayout.East )

        label_s = self.createLabel( "South" )
        layout.addWidget( label_s, BorderLayout.South )

        self.setLayout( layout )

        self.setWindowTitle( self.tr( "Border Layout" ) )

    def createLabel( self, text ):
        label = QtGui.QLabel( text )
        label.setFrameStyle( QtGui.QFrame.Box | QtGui.QFrame.Raised )
        return label


if __name__ == "__main__":
    app = QtGui.QApplication( sys.argv )
    window = Window()
    window.show()
    sys.exit( app.exec_() )