Simple traits/chaco example

rectangle.py

import numpy as np
from traits.api import *
from traitsui.api import *
from chaco.api import Plot, ArrayPlotData
from enable.component_editor import ComponentEditor


class Rectangle(HasTraits):

    width = Range(0.0, 10.0)

    height = Range(0.0, 10.0)

    x0 = Float(0.0)

    y0 = Float(0.0)

    perimeter = Property(Float, depends_on='height, width')

    area = Property(Float, depends_on='height, width')

    x = Property(Array, depends_on='x0, width')

    y = Property(Array, depends_on='y0, height')

    plot = Instance(Plot)

    plot_data = Instance(ArrayPlotData)

    def _get_perimeter(self):
        return 2 * self.height + 2 * self.width

    def _get_area(self):
        return self.height * self.width

    def _get_x(self):
        """ Calculate x coordinates of corners """
        x1 = self.x0 + self.width
        return np.array([self.x0, x1, x1, self.x0, self.x0])

    def _get_y(self):
        """ Calculate y coordinates of corners """
        y1 = self.y0 + self.height
        return np.array([self.y0, self.y0, y1, y1, self.y0])

    def _plot_default(self):
        self.plot_data = ArrayPlotData(x=self.x, y=self.y)
        plot = Plot(self.plot_data)
        plot.plot(('x', 'y'), type='line', color='blue', line_width=2.0)
        plot.x_axis.mapper.range.set(low=0.0, high=10.0)
        plot.y_axis.mapper.range.set(low=0.0, high=10.0)
        return plot

    def _x_changed(self):
        if self.plot_data is not None:
            self.plot_data.set_data('x', self.x)

    def _y_changed(self):
        if self.plot_data is not None:
            self.plot_data.set_data('y', self.y)

    view = View(VGroup(Item('height'),
                       Item('width'),
                       Item('area', style='readonly'),
                       Item('perimeter', style='readonly'),
                       Item('plot', editor=ComponentEditor(), show_label=False,
                            width=500, height=500, resizable=True),
                    )
                )


if __name__ == '__main__':
    r = Rectangle(width=4.0, height=3.0)
    r.configure_traits()