PIL Interaction

The wrapper now supports the Python Imaging Library. Now you can create a chart and fetch the PIL image instance of that chart to display or manipulate however you please. The GChart.image method now returns a PngImageFile instance of the chart. You must install the Python Imaging Library to use these features. The PIL has other image manipulation features like image blending and filtering which can be found in the PIL Handbook

API

The Python API extends the GChart main class, but can be used for any subtype.

# Create a simple Google-O-Meter with a label
>>> G = Meter(70).label('Hello').size(225,125)
>>> str(G)
'http://chart.apis.google.com/chart?chl=Hello&chs=225x125&cht=gom&chd=t:70.0'

# Now fetch the PngImageFile
>>> G.image()
<PngImagePlugin.PngImageFile instance at 0xb795ee4c>

# Now that you have the image instance, the world is your oyster
# Try saving image as JPEG,GIF,etc.
>>> G.image().save('google-o-meter.jpg','JPEG')

Advanced Usage

The following example takes a chart image and overlays the Google Code logo on top of it as a watermark. You could easily use your own graphics to create a custom overlay.

import Image, ImageEnhance
from GChartWrapper import Pie3D

# Main image from chart
image = Pie3D( [1,2,3,4] ).label('A','B','C','D').color('00dd00').image()

# Image to overlay as watermark
# http://www.gstatic.com/codesite/ph/images/code_sm.png
mark = Image.open("code_sm.png")

# Set position and opacity of overlay
position,opacity = (150, 100), 0.2
# Convert to RGBA if needed
mark = mark.convert('RGBA')

# Get alpha layer and lower brightness 
alpha = mark.split()[3]
alpha = ImageEnhance.Brightness(alpha).enhance(opacity)
mark.putalpha(alpha)

# Create new image of the watermark
layer = Image.new('RGBA', image.size, (0,0,0,0))
layer.paste(mark, position)

# Composite the watermark with the chart image
Image.composite(layer, image, layer).show()