Signaturepad 2 Image Utility for Python (c.) Alan Viars - Videntity Systems Inc. - 2011

This library is dual licensed. It is realeased under the GPL licnese agreement and under a commercial license by Videntity systems Inc if you seek support or a non-free license. This library is designed to work with the JQuery Plugin, SigntaurePad , from Thomas J. Bradley.

http://thomasjbradley.ca/lab/signature-pad

Python Imaging Library (PIL) is required to use this package. Install PIL with the following command: :: sudo pip install PIL

..or if you don't have PIP installed you can install it with :: sudo easy_install PIL

Use easy_install to install the program. :: cd python-sigpad2image sudo easy_install setup.py install

The package has two functions: 's2if' and 's2i'. s2if writes the resulting image to a file. s2i returns an image object. s2i is ideal for most web applications where you are returning an image to the browser.

Action: Creates an image from the JSON string and writes it to a file.

• jsonsig - The JSON representing the signature.
• output_image- The path to the default image. Default="signature.png",
• input_image- The path to the input image. Default="blanksig.png",
• pin_color - the ink's color. Default=(0,0,255). This is blue.

Returns: ~~~~~~~ * str - A string containing the output image path.

A simple example using straigh-up python. :: from sigpad2image.sigpad2image import s2if

j="""[{"lx":32,"ly":13,"mx":32,"my":12}...""" image_path=s2if(j, output_image) print "New signature image written to: %s " % (image_path)

Action: Return an image from the JSON string. If it fails or if, force_no_sig_image=True then it returns nosig_image, which by default is an image with the text "No Signature".

• jsonsig - The JSON representing the signature.
• output_image- The path to the default image. Default="signature.png",
• input_image- The path to the input image. Default="blanksig.png",
• pin_color - the ink's color. Default=(0,0,255). This is blue.
• force_no_sig_image - Setting this to true will force the return of the no_sig image. Default=False.
• nosig_image- The image to return if no JSON is found. Default="nosig.png"

Returns: ~~~~~~~ * An Image object. If successful it will contain an image of the signature. If an error orccurs or the force_no_sig_image is set to True, it will return the nosig_image.

Thhis illustrates building the image and returning it as an HTTP response. This illustration is a django view. Note the vaiables NO_SIG_IMAGE and BLANK_SIG_IMAGE are being imported from the settings file. :

from sigpad2image.sigpad2image import s2i
from django.http import HttpResponse
from models import Signature
from django.conf import settings

def render_signature(request, user_id):
    #create a response objects and set its mimetype to image/png
        response = HttpResponse(mimetype="image/png")
        try:
        #Get the JSON Signature from the database               
        s=Signature.objects.get(user=user_id)
        #build the new image
        image = s2i(s.signature, input_image=settings.BLANK_SIG_IMAGE)
        except(Signature.DoesNotExist):
        #If it wasn't in the database, then return the nosig image
            image = s2i("", force_no_sig_image=True, nosig_image=settings.NO_SIG_IMAGE)
    #return the HttpResponse object to the client.          
    image.save(response, "PNG")
        return response