GoogleCharts and the GChart Wrapper

Customizable charts can be generated using the Google Chart API. The GChart Wrapper allows python access to the parameters of constructing the charts and displaying the URLs generated.

Constructing

class GChart(UserDict)
    """Main chart class
    
    chart type must be valid for cht parameter
    dataset can be any python iterable
    kwargs will be put into chart params if valid"""
    def __init__(self, ctype, dataset, **kwargs):

The chart takes any iterable python data type and does the encoding for you

# Datasets 
>>> dataset = (1, 2, 3)
# Also 2 dimensional
>>> dataset = [[3,4], [5,6], [7,8]]

Initialize the chart with a valid type (see API reference) and dataset

# 3D Piechart
>>> GChart('p3', dataset)
<GChart  p3 (1, 2, 3)>

# Encoding (simple/text/extended)
>>> G = GChart('p3', dataset, encoding='text')

# maxValue (for encoding values)
>>> G = GChart('p3', dataset, maxValue=100)

# Size
>>> G = GChart('p3', dataset, size=(300,150))

# OR directly pass in API parameters
>>> G = GChart('p3', dataset, chtt='My Cool Chart', chl='A|B|C')

Rendering

As the chart URL itself using str

>>> str(G)
'http://chart.apis.google.com/chart?...'

As an HTML img tag, kw arguments can be valid tag attributes

>>> G.img(height=500,id="chart")
'<img alt="" title="" src="http://chart.apis.google.com/chart?..." id="chart" height="500" >'

Grab a GChart object from an existing Google chart url

>>> G = GChart.fromurl('http://chart.apis.google.com/chart?ch...')
<GChart instance at...>

Viewing

Save chart to file as PNG image, returns filename

>>> G.save('May')
'May.png'

Show URL directly in default web browser

>>> G.show()

Chaining

One of the new features involves chaining the methods together. For example, you could write this

>>> G = Pie3D(range(1,5))
>>> G.label('A','B','C','D')
>>> G.color('00dd00')
>>> print G

But you would probably much rather write this

>>> print Pie3D(range(1,5)).label('A','B','C','D').color('00dd00')

The wrapper returns a copy of itself at each link in the chain, so combining methods onto one line is really easy and saves time and space