removing all padding / white space around plot


I've searched the archives but can't find a solution to this problem.
I'd like to remove the whitespace, padding, offset, etc on the left and
right of the plot as I'm writing the entire thing to a jpg. I've turned
the frame, axes, ticks off, but the space still remains.

I've attached the code and the resulting image.

code (inside a django app):

def hours_chart(request):
    from PIL import Image as PILImage
    from matplotlib.backends.backend_agg import FigureCanvasAgg as
    from matplotlib.figure import Figure
    from matplotlib.axes import Axes
    from StringIO import StringIO
    fig = Figure(figsize=(3,1),facecolor='r') # w,h in inches
    fig.frameon = False
    canvas = FigureCanvas(fig)
    ax = fig.add_subplot(111)
    values = [d.get_total_hours() for d in
Debrief.objects.all().order_by('date')] # the data
    size = canvas.get_renderer().get_canvas_width_height()
    im=PILImage.fromstring('RGB', size, buf, 'raw', 'RGB', 0, 1)
    imdata=StringIO(), format='JPEG')
    response = HttpResponse(imdata.getvalue(), mimetype='image/jpeg')
    return response

This is the result -- as you can see there's a lot of white space on the
left of the plot: