Use QrCodeWidget (or PlotArea) with platypus

Question

My django app is using a multi-frames reportlab pdf report in witch I would like to add some barcodes/qr-codes.

The problem I have is that every object I add to my layout have to be a Flowable. So the question would be as to cast a PlotArea (mother class of QrCodeWidget) as Flowable.

If we have an answer here the error message we can get if we add the QrCodeWidget as

AttributeError: QrCodeWidget instance has no attribute 'getKeepWithNext'

Answer 1

Ok, I made my own Flowable, it was simpler than I taught.

It's as simple as doing it on a canva with this API.

from reportlab.platypus import Flowable
from reportlab.graphics.barcode import qr
from reportlab.graphics import renderPDF
from reportlab.graphics.shapes import Drawing

class QRFlowable(Flowable):
    # usage : 
    # story.append(QRFlowable("http://google.fr"))
    def __init__(self, qr_value):
        # init and store rendering value
        Flowable.__init__(self)
        self.qr_value = qr_value

    def wrap(self, availWidth, availHeight):
        # optionnal, here I ask for the biggest square available
        self.width = self.height = min(availWidth, availHeight)
        return self.width, self.height

    def draw(self):
        # here standard and documented QrCodeWidget usage on
        # Flowable canva
        qr_code = qr.QrCodeWidget(self.qr_value)
        bounds = qr_code.getBounds()
        qr_width = bounds[2] - bounds[0]
        qr_height = bounds[3] - bounds[1]
        w = float(self.width)
        d = Drawing(w, w, transform=[w/qr_width, 0, 0, w/qr_height, 0, 0])
        d.add(qr_code)
        renderPDF.draw(d, self.canv, 0, 0)

Answer 2

You should generate an image from your QrCodeWidget and include that in an Image flowable.