Web graph producing library

[Fredrik Lundh]

"VanL" <vlindberg at verio.net> wrote:

> I have googled around for this, and I can't find it.
>
> I have a web app that produces some reports.  I would like to produce
> some reports in graph form, as well.  I have found a couple interfaces
> to various image libraries, but none that are particularly specialized
> for graphs.
>
> For example I would love to have something like this:
>
> import webgraph
>
> data = {'adam': (30, 'yellow'),
>          'jeff': (40, 'green'),
>          'rob': (10, 'red'),
>          'bill': (2, 'purple'),
>          'bob': (15, 'black'),
>          'uneaten': (3, 'white')
>         }
> title = "Apples eaten by team member"
>
> piechart = webgraph.PieChart(data, title=title)
>
> piechart.dump() # Dumps pie graph in png (or other) format

here's the first part of your webgraph library:

# requires PIL 1.1.4
from PIL import Image, ImageDraw, ImageFont

# path to nice truetype font
FONTFILE = "arial.ttf"

def PieChart(data, title=None, size=400):

    items = data.items()
    items.sort()

    im = Image.new("P", (size+200, size+50))

    draw = ImageDraw.Draw(im)
    draw.rectangle((0, 0) + im.size, fill="white")

    bbox = (10, 50+10, size-20, size+50-20)

    angle = 0

    x = size + 20
    y = 50

    font = ImageFont.truetype(FONTFILE, 10)

    total = 0
    for name, (value, color) in items:
        total = total + value

    for name, (value, color) in items:
        slice = 360.0 * value / total
        draw.pieslice(bbox, angle, angle + slice, fill=color, outline="black")
        angle = angle + slice
        draw.rectangle((x, y, x+10, y+10), fill=color, outline="black")
        draw.text((x + 15, y), name, font=font, fill="black")
        y = y + 12

    if title:

        font = ImageFont.truetype(ARIAL, 20)
        draw.text((10, 10), title, font=font, fill="black")

    return im

#
# usage:

piechart = PieChart(data, title=title)
piechart.save("out.png")

# or piechart.save(sys.stdout. "PNG")

for more info about PIL, see:

    http://www.pythonware.com/products/pil/
    http://effbot.org/zone/pil-index.htm
    http://effbot.org/zone/pil-changes-114.htm

</F>