pyqt4 - Python PyQt: How can I move my widgets on the window with mouse?

Question

I am new to Python. I have drawn polygon and circle with fixed coordinates. Now I want to move this polygon and circle using mouse to some other place on window. Please guide me how can I do it?

import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *

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

    def paintEvent(self, event=None):
            paint=QPainter(self)
            paint.setPen(QPen(QColor(Qt.green).dark(150),1,Qt.SolidLine))
            segColor=QColor(Qt.green).dark(150)
            paint.setBrush(segColor)
            paint.setBrushOrigin(QPoint(225,225))
            polygon=QPolygon([QPoint(250,175), QPoint(265,175), QPoint(250,190), QPoint(265,190),QPoint(250,175)])
            paint.drawPolygon(polygon)
            paint.setPen(QPen(QColor(Qt.red),1,Qt.SolidLine))
            paint.setBrush(QBrush(Qt.NoBrush))
            polygon1=QPolygon([QPoint(250,300), QPoint(250,500), QPoint(350,500), QPoint(350,300)])
            paint.drawPolyline(polygon1)
            paint.drawEllipse(50,50,50,50)


app=QApplication(sys.argv)
f=MyFrame()
f.show()
app.exec_()

Answer 1

You should look into the QGraphicsView instead of what you are doing, it has this all built in already.

http://doc.qt.nokia.com/4.7-snapshot/qgraphicsview.html

http://doc.qt.nokia.com/4.7-snapshot/qgraphicsscene.html

from PyQt4 import QtGui, QtCore

class MyFrame(QtGui.QGraphicsView):
    def __init__( self, parent = None ):
        super(MyFrame, self).__init__(parent)

        self.setScene(QtGui.QGraphicsScene())

        # add some items
        x = 0
        y = 0
        w = 45
        h = 45
        pen = QtGui.QPen(QtGui.QColor(QtCore.Qt.green))
        brush = QtGui.QBrush(pen.color().darker(150))

        item = self.scene().addEllipse(x, y, w, h, pen, brush)
        item.setFlag(QtGui.QGraphicsItem.ItemIsMovable)

if ( __name__ == '__main__' ):
    app = QtGui.QApplication([])
    f = MyFrame()
    f.show()
    app.exec_()

Edit: Showing how to create a QPainterPath

from PyQt4 import QtGui, QtCore

class MyFrame(QtGui.QGraphicsView):
    def __init__( self, parent = None ):
        super(MyFrame, self).__init__(parent)

        scene = QtGui.QGraphicsScene()
        self.setScene(scene)

        # add some items
        x = 0
        y = 0
        w = 45
        h = 45
        pen   = QtGui.QPen(QtGui.QColor(QtCore.Qt.green))
        brush = QtGui.QBrush(pen.color().darker(150))

        item = scene.addEllipse(x, y, w, h, pen, brush)
        item.setFlag(QtGui.QGraphicsItem.ItemIsMovable)

        # create an open path
        path = QtGui.QPainterPath()
        path.moveTo(-w, -h)
        path.lineTo(-w, h)
        path.lineTo(w, h)
        path.lineTo(w, -h)

        clr   = QtGui.QColor('blue')
        clr.setAlpha(120)
        brush = QtGui.QBrush(clr)
        pen   = QtGui.QPen(QtCore.Qt.NoPen)
        fill_item = scene.addRect(-w, y, w*2, h, pen, brush)
        path_item = scene.addPath(path)

if ( __name__ == '__main__' ):
    app = QtGui.QApplication([])
    f = MyFrame()
    f.show()
    app.exec_()