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Download pdf with filled data in acroform - PDFJS

I am integrating PDF JS in my web application with enabled renderIntrectiveForm property. So I am able to edit the form input in PDF, I am able to fill inputs. But the problem is I am not able to download the PDF with filled data.
I searched as much as I can. And I tried so hard to achieve the functionality. I also tried to update annotation manually as in below code in download function. But still, it is downloading the original PDF.
var pdf = PDFViewerApplication.pdfDocument;
var downloadManager = PDFViewerApplication.downloadManager;
pdf.loadingTask.then(function(data){
data.getPage(1).then(function(page){
page.getAnnotations().then(function(annotations){
annotations[1].fieldValue= "New Text"
pdf.getData().then(function(blobData){
var blob = (0, PDFJS.createBlob)(blobData, 'application/pdf');
downloadManager.download(blob, "a.pdf", "a.pdf");
})
})
})
});
I know i can send json to server and then create a new pdf with json(as in https://www.smartformsondemand.org). But I want to do it with client side only.

Django request.FILES is empty when saving canvas image

I am creating a webapp where the an image is shown to the user and the user can draw on the image (basically the image is in a canvas).
Now once the user is done drawing, the user will press the save button and the image needs to be saved in static folder (not locally). Since I am using Django to accomplish this; my request.FILES is always empty whenever I call the route.
My question is how can I save the canvas on which the user drew to a folder in the project and not locally.
index.html
<div id="uploaderForm">
<form enctype="multipart/form-data" action="{% url 'addImg' %}" method="post">
<input type="hidden" for="image_data" id="image_data" name="image_data" />
</form>
<div class="uploaderItem" id="uploaderSubmit">
Add to the gallery
</div>
</div>
script.js
function addImage()
{
console.log("In add image");
var image_data = canvas.toDataURL();
console.log("Image data:", image_data);
$('#image_data').val(image_data);
$('#uploaderForm > form').submit()
}
views.py
def add(request):
print request.FILES
#print request.POST['image_data']
return HttpResponse("You're looking at question")

the FILES array is reserved for files uploaded in file input fields through a multipart form. What you're doing is passing a base-64 encoded string representing your image, to a hidden text field that is then sent to your server. By your code, the image should be found here:
image_data = request.POST.get('image_data')
It will be a base-64 string, so you'll need to decode it, the example below can be applied to almost any data URL, but the format will depend on your browser, so it's kinda tricky:
import re
pattern = r'^data:(?P<mime_type>[^;]+);base64,(?P<image>.+)$'
result = re.match(pattern, image_data)
if result:
mime_type = result.group('mime_type')
image = result.group('image').decode('base64')
Be careful: by not using a file as transport, you are basically dumping the whole image in the server's memory, and that's expensive if you're planning to serve a lot of clients, and it's also time consuming, so your request could timeout before you are done with the image.
To fix this, you should consider uploading the image through AJAX, which is a supported way to treat Blobs in javascript, that way you could use Django's file upload facilities more efficiently

How to display raw image data with html and javascript?

I have an ajax application where the PHP side sends uncoded raw image data, coming from a camera, to the client javascript side.
I would like to display the image via html and javascript using img or canvas tags.
Image data are 32*32 unsigned char.
I would like to do, whatever it takes to reach my goal (encoding or everythig else), but I want to do it at client side beacause I cannot handle any other operation at the server side.
I tried to encode raw data into jpeg or png data but without success.
I post an example that doesn't work:
var encoder = new JPEGEncoder(9);
var jpgFile = encoder.encode(rawImage, 9);
document.getElementById("image").src = jpgFile;
jpgFile is like
data:image/jpeg;base64,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
I got JPEGEncoder googling on internet.

Tried it for you =)
http://jsfiddle.net/bYGum/
All you have to do is make sure your string is base64 encoded and do the exact same thing you have already written:
document.getElementById("image").src = jpgFile;

Uploading JavaScript generated image to Django

I have an image generated on the client side which I want to transfer to the server through a form. For example, let's say that I have a registration form in which the profile image is generated automatically by JavaScript, and I want to transfer that image to django.
What is the best way to transfer the image binary data to the server when user hit the submit button? what form field should I use?
thanks!

Found an answer myself, here's the solution in case someone needs it:
In the client side, this is how you get the image from canvas and set it to a form field (a hidden char field):
var dataURL = document.getElementById('canvas_id').toDataURL("image/png");
document.getElementById('id_hidden_image_field').value = dataURL;
And in django side:
add to the form a hidden field called 'hidden_image_field', which will be used to pass the data. this field is a simple CharField. you can add max_length limit to make sure image is in a reasonable size (note: not dimensions but actual size).
to parse the image data:
import re
import base64
dataUrlPattern = re.compile('data:image/(png|jpeg);base64,(.*)$')
ImageData = request.POST.get('hidden_image_field')
ImageData = dataUrlPattern.match(ImageData).group(2)
# If none or len 0, means illegal image data
if (ImageData == None or len(ImageData) == 0:
# PRINT ERROR MESSAGE HERE
pass
# Decode the 64 bit string into 32 bit
ImageData = base64.b64decode(ImageData)
and now ImageData contains the binary data, you can simply save to a file and it should work.
hope this helps.

HTML5 - Attach image to mail using Java EE

I am developing an a drawing application using Javascript.
Users will be able to draw on a canvas. Once they are done with drawing, they will be able to convert it into an image (Convert to image button).
This is the code:
function putImage()
{
var canvas1 = document.getElementById("canvas");
if (canvas1.getContext)
{
var ctx = canvas1.getContext("2d");
var myImage = canvas1.toDataURL("image/png");
}
var imageElement = document.getElementById("MyPix");
imageElement.src = myImage;
$('#submit_btn').closest('.ui-btn').show();
}
There's a submit button and when the users click on it, the application will redirect to another page whereby the user will be able to send an email (using java mail) with the image attached to it.
The page allows user to type in the email address that they wanna send to, and the body of the email.
May i know how to make the image auto-attach to the email so that the after the user type in the email address and the body, they will be able to send the mail?
Thanks in advance!

To send the image as an attachment with javamail, you need the bytes from say a jpg or bmp. What you'll need to do is send the model, eg the coordinates, to the server and recreate the image server side. Perhaps a html5 canvas has direct support for outputting the images as bytes, I don't know, but that would help. In that case you'd simply transfer those bytes to the server for attaching to the mail.

HTML5 Canvas has a cool api trick to do this:
var encodedImage = canvas1.toDataURL(); //this generates base64 encoded image in png
//for jpeg
var encodedImage = canvas1.toDataURL("image/jpeg");
Now you can store that encodedImage in back-end in a table or file. If you want to show it on a page, just assign it back to html img tag to source property