Python save matplotlib figure on an PIL Image object

Question

HI, is it possible that I created a image from matplotlib and I save it on an image object I created from PIL? Sounds very hard? Who can help me?

Answer 1

To render Matplotlib images in a webpage in the Django Framework:

• create the matplotlib plot

• save it as a png file

• store this image in a string buffer (using PIL)

• pass this buffer to Django's HttpResponse (set mime type image/png)

• which returns a response object (the rendered plot in this case).
  
  

In other words, all of these steps should be placed in a Django view function, in views.py:

from matplotlib import pyplot as PLT
import numpy as NP
import StringIO
import PIL
from django.http import HttpResponse 


def display_image(request) :
    # next 5 lines just create a matplotlib plot
    t = NP.arange(-1., 1., 100)
    s = NP.sin(NP.pi*x)
    fig = PLT.figure()
    ax1 = fig.add_subplot(111)
    ax1.plot(t, s, 'b.')

    buffer = StringIO.StringIO()
    canvas = PLT.get_current_fig_manager().canvas
    canvas.draw()
    pil_image = PIL.Image.fromstring('RGB', canvas.get_width_height(), 
                 canvas.tostring_rgb())
    pil_image.save(buffer, 'PNG')
    PLT.close()
    # Django's HttpResponse reads the buffer and extracts the image
    return HttpResponse(buffer.getvalue(), mimetype='image/png')