A fiddle example for PyQt4

pyqt_example.py

#!/bin/env python
# coding: utf-8

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

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.filename = None
        self.dirty = False
        self.listWidget = QListWidget()
        self.setCentralWidget(self.listWidget)
        fileNewAction = self.createAction("&New...", self.fileNew,
            QKeySequence.New, "filenew")
        fileOpenAction = self.createAction("&Open...", self.fileOpen,
            QKeySequence.Open, "fileopen")
        fileSaveAction = self.createAction("&Save", self.fileSave,
            QKeySequence.Save, "filesave")
        fileMenu = self.menuBar().addMenu("&File")
        fileMenu.addAction(fileNewAction)
        fileMenu.addAction(fileOpenAction)
        fileMenu.addAction(fileSaveAction)
        fileToolbar = self.addToolBar("File")
        fileToolbar.addAction(fileNewAction)
        fileToolbar.addAction(fileOpenAction)
        fileToolbar.addAction(fileSaveAction)
        self.statusBar().showMessage("Ready...", 5000)
        self.setWindowTitle("ListKeeper - Unnamed List")
        
    def editAdd(self):
        form = AddForm(self)
        if form.exec_():
            if form.addAtEnd:
                self.listWidget.addItem(form.text)
            else:
                self.listWidget.insertItem(0, form.text)
            self.dirty = True
            
    class AddForm(QDialog):
        def __init__(self, parent=None):
            super(AddForm, self).__init__(parent)
            self.textLineEdit = QLineEdit()
            label = QLabel("&Add Text:")
            label.setBuddy(self.textLineEdit)
            self.addAtStartRadioButton = QRadioButton("Add at &Start")
            self.addAtEndRadioButton = QRadioButton("Add at &End")
            self.addAtEndRadioButton.setChecked(True)
            buttonBox = QDialogButtonBox(QDialogButtonBox.Ok | QDialogButtonBox.Cancel)
            topLayout = QHBoxLayout()
            topLayout.addWidget(label)
            topLayout.addWidget(self.textLineEdit)
            middleLayout = QHBoxLayout()
            middleLayout.addWidget(self.addAtStartRadioButton)
            middleLayout.addWidget(self.addAtEndRadioButton)
            layout = QVBoxLayout()
            layout.addLayout(topLayout)
            layout.addLayout(middleLayout)
            layout.addStretch()
            layout.addWidget(buttonBox)
            self.setLayout(layout)            
            buttonBox.accepted.connect(self.accept)
            buttonBox.rejected.connect(self.reject)
            self.setWindowTitle("ListKeeper - Add")
            
    def accept(self):
        self.text = self.textLineEdit.text()
        if self.text.isEmpty():
            super(AddForm, self).reject()
        else:
            self.addAtEnd = self.addAtEndRadioButton.isChecked()
            super(AddForm, self).accept()            
            
class Squiggly(QWidget):
    textChanged = pyqtSignal(str)
    def __init__(self, parent=None):
        super(Squiggly, self).__init__(parent)
        font = self.font()
        font.setPointSize(font.pointSize() + 80)
        self.setFont(font)
        mstring = 'I rule'
        self.text = QString(mstring)
        self.step = 0;
        self.setWindowTitle(mstring)
        self.resize(500, 360)
        self.timer = QBasicTimer()
        self.timer.start(20, self)            

    def timerEvent(self, event):
        if (event.timerId() == self.timer.timerId()):
            self.step += 1
            self.update()
        else:
            super(Squiggly, self).timerEvent(event)
            
    def paintEvent(self, event):
        sines = (0, 38, 71, 92, 100, 92, 71, 38, 0, -38, -71, -92, -100, -92, -71, -38)
        fm = QFontMetrics(self.font())
        x = (self.width() - fm.width(self.text)) / 2
        y = (self.height() + fm.ascent() - fm.descent()) / 2
        color = QColor()
        painter = QPainter(self)
        for i in range(self.text.size()):
            index = (self.step + i) % 16
            color.setHsv((15 - index) * 16, 255, 191)
            painter.setPen(color)
            painter.drawText(x, y - ((sines[index] * fm.height()) / 400), self.text[i])
            x += fm.width(self.text[i])   
            
    def keyPressEvent(self, event):
        if event.key() in (Qt.Key_Q, Qt.Key_X, Qt.Key_Escape):
            self.close()
        else:
            super(Squiggly, self).keyPressEvent(event)
            
    def mousePressEvent(self, event):
        text, ok = QInputDialog.getText(self, "Squiggly - Set Text", "Text:",
            QLineEdit.Normal, self.text)
        if ok and not text.isEmpty():
            self.text = text
            self.update()
            self.textChanged.emit(self.text)            
            
if __name__ == "__main__":
    app = QApplication(sys.argv)
    squiggly = Squiggly()
    squiggly.show();
    app.exec_()