PyQt Charts

The Qt framework doesn’t contain any useful charting widgets. There are a few python charting modules out there, most notably PyQwt. As a PyQt developer I didn’t find this module very useful. What I really wanted was a charting widget that used QWidget as its base class. At the time of this post I couldn’t find anything so I wrote my own based on the google charts module.

What I love about this snippet is that it mimics the C++ template functionality in Python. The QChart function below abstracts the PyQtChart class definition and any pygooglechart object can be instantiated as a QWidget.

__author__	  = "Christopher Piekarski"
__email__	  = "@c_piekarski"

import time, os, sys
from PyQt4 import QtCore, QtGui
from pygooglechart import *

def QChart(parent, type, **kwargs):
	class PyQtChart(type, QtGui.QWidget):
		def __init__(self, parent, **kwargs):
			QtGui.QWidget.__init__(self, parent, **kwargs)
			type.__init__(self, kwargs["size"].width(), kwargs["size"].height())
			self.pix = QtGui.QPixmap()

		def download(self):
			file = "./%f.png" % time.time()
			type.download(self, file)
			self.pix.load(file)

		def paintEvent(self, event):
			p = QtGui.QPainter(self)
			p.drawPixmap(0,0,self.pix)
			super(PyQtChart, self).paintEvent(event)

	return PyQtChart(parent, **kwargs)

class MainWindow(QtGui.QMainWindow):
	def __init__(self, **kwargs):
		super(QtGui.QMainWindow, self).__init__(**kwargs)

		t = QChart(self, PieChart3D, size=QtCore.QSize(250,100))
		t.add_data([10,20])
		t.set_pie_labels(['Hello', 'World'])
		t.download()

if __name__ == '__main__':
	app = QtGui.QApplication(sys.argv)
	app.setApplicationName("PyQt Charting Demo")
	app.setQuitOnLastWindowClosed(True)

	scaledSize = QtCore.QSize(500,500)
	window = MainWindow(size=scaledSize)
	window.setWindowTitle("PyQt Charting Demo")
	window.show()

	sys.exit(app.exec_())

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