Aug 21 2008

drawing images on google app engine

Tag: Uncategorizeddenis @ 4:59 pm

The google app engine image api looks nice before you actually use it. Why? Because it lacks a fundamental feature: the capability to draw an image. That’s right: no trace of a classic canvas api (setpixel, getpixel, rectangle, circle, etc).

Luckily, some clever programmer wrote a PNGCanvas class that saved the day. Here’s how to use it:

from pngcanvas import PNGCanvas
class ImageTest(webapp.RequestHandler):
 def get(self):
  img = PNGCanvas(256, 256, [0, 0,0,0])
  for i in range(0, 256):
   img.point(i, i, [0xff, 0, 0, 0xff])
  self.response.headers['Content-Type'] = "image/png"
  self.response.out.write(img.dump())

This example runs at http://pngcanvas.appspot.com/image

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