ChartDirector Ver 4.1 (Python Edition)

3D Shadow Mode


      

This example demonstrates an alternative 3D drawing method that uses shadows.

The standard way to draw a pie chart in 3D is to view the chart from an inclined angle. Using this method, the surface of a 3D pie will become an ellipse.

ChartDirector supports an alternative way to draw a pie chart in 3D - to draw the 3D portion like a shadow. The 3D pie will remain perfectly circular, and the sector areas will correctly reflect its percentages.

The 3D drawing method is configured using PieChart.set3D.

Source Code Listing

[Standalone Version] pythondemo\shadowpie.py
#!/usr/bin/python
from pychartdir import *

def createChart(img) :

    # the tilt angle of the pie
    angle = int(img) * 90 + 45

    # The data for the pie chart
    data = [25, 18, 15, 12, 8, 30, 35]

    # Create a PieChart object of size 100 x 110 pixels
    c = PieChart(100, 110)

    # Set the center of the pie at (50, 55) and the radius to 36 pixels
    c.setPieSize(50, 55, 36)

    # Set the depth, tilt angle and 3D mode of the 3D pie (-1 means auto depth,
    # "true" means the 3D effect is in shadow mode)
    c.set3D(-1, angle, 1)

    # Add a title showing the shadow angle
    c.addTitle("Shadow @ %s deg" % (angle), "arial.ttf", 8)

    # Set the pie data
    c.setData(data)

    # Disable the sector labels by setting the color to Transparent
    c.setLabelStyle("", 8, Transparent)

    # output the chart
    c.makeChart("shadowpie%s.png" % img)


createChart("0")
createChart("1")
createChart("2")
createChart("3")

[CGI Version] pythondemo_cgi\shadowpie.py
#!/usr/bin/python
from pychartdir import *
import cgi

# Get HTTP query parameters
query = cgi.FieldStorage()

# the tilt angle of the pie
angle = int(query["img"].value) * 90 + 45

# The data for the pie chart
data = [25, 18, 15, 12, 8, 30, 35]

# Create a PieChart object of size 100 x 110 pixels
c = PieChart(100, 110)

# Set the center of the pie at (50, 55) and the radius to 36 pixels
c.setPieSize(50, 55, 36)

# Set the depth, tilt angle and 3D mode of the 3D pie (-1 means auto depth, "true"
# means the 3D effect is in shadow mode)
c.set3D(-1, angle, 1)

# Add a title showing the shadow angle
c.addTitle("Shadow @ %s deg" % (angle), "arial.ttf", 8)

# Set the pie data
c.setData(data)

# Disable the sector labels by setting the color to Transparent
c.setLabelStyle("", 8, Transparent)

# output the chart
print "Content-type: image/png\n"
binaryPrint(c.makeChart2(PNG))