Django Generate Barcode With Reportlab
After Django With Barcode and Qrcode and Django Return Pdf With Reportlab I need something new in my Django server. I need a barcode generator for labeling stuffs.
The problem
Every code is a solution to a pratical problem. In this case I need to make the barcode labels with text for keep an inventory. The basic solution is generate a pdf/img file to print into sticker’s paper and cut it after.
So, I need the data to convert into lable (the string on top to the barcode) and the barcode (or the qrcode) as in the screenshot, so I wrote this code for do it for pages and ready to print and stick it all around the world!
Code
The view
This code is the view for generating download link for the pdf with all the barcode.
from django.views.generic import View
class ExampleBarcodePdf(View):
bar_height = None
position_text_y = None
filename = "ExampleBarCode.pdf"
def get(self, request, *args, **kwargs):
super().get(request, *args, **kwargs)
response = HttpResponse(content_type="application/pdf")
response["Content-Disposition"] = (
'attachment; filename="' + self.filename + '"'
)
a4p = A4PrinterBarcode()
pdf = a4p.get_pdf(
buffer=BytesIO(),
datas=[{barcode:"0000000000000", "label"}, {"999999999999", "other label"}],
bar_height=self.bar_height,
position_text_y=self.position_text_y,
)
response.write(pdf)
return responseThe pdf generator
This is the “printer” the code for generate pdf. After the import you find the constant with define the pdf.ß
from reportlab.graphics.barcode.eanbc import Ean13BarcodeWidget
from reportlab.graphics.shapes import Drawing
from reportlab.graphics.shapes import String
from reportlab.lib.pagesizes import A4
from reportlab.pdfgen import canvas
PAGESIZE = A4
NUM_LABELS_X = 3
NUM_LABELS_Y = 8
BAR_WIDTH = 1.5
BAR_HEIGHT = 51.0
TEXT_Y = 80
BARCODE_Y = 17
FONT_SIZE = 8
LABEL_WIDTH = PAGESIZE[0] / NUM_LABELS_X
LABEL_HEIGHT = PAGESIZE[1] / NUM_LABELS_Y
SHEET_TOP = PAGESIZE[1]
class A4PrinterBarcode:
def generate_label(
self,
ean13: str,
description: str,
label_w: float = 0.0,
label_h: float = 0.0,
bar_with: float = BAR_WIDTH,
bar_height: float = BAR_HEIGHT,
postion_text_y: float = TEXT_Y,
font_size: int = FONT_SIZE,
) -> Drawing:
"""
Generate a drawing with EAN-13 barcode and descriptive text.
:param ean13: The EAN-13 Code.
:type ean13: str
:param description: Short product description.
:type description: str
:return: Drawing with barcode and description
:rtype: Drawing
"""
if label_w == 0.0:
label_w = A4[0] / NUM_LABELS_X
if label_h == 0.0:
label_h = A4[1] / NUM_LABELS_Y
text = String(
0,
postion_text_y,
description,
fontName="Helvetica",
fontSize=font_size,
textAnchor="middle",
)
text.x = label_w / 2
barcode = Ean13BarcodeWidget(ean13)
barcode.barWidth = bar_with
barcode.barHeight = bar_height
_, _, bw, _ = barcode.getBounds()
barcode.x = (label_w - bw) / 2 # center barcode
barcode.y = 18 # spacing from label bottom (pt)
label_drawing = Drawing(label_w, label_h)
label_drawing.add(text)
label_drawing.add(barcode)
return label_drawing
def get_pdf(
self,
buffer,
datas: list,
bar_height: float = None,
position_text_y: float = None,
) -> bytes:
if bar_height is None or bar_height < 0:
bar_height = BAR_HEIGHT
if position_text_y is None or position_text_y < 0:
position_text_y = TEXT_Y
p = canvas.Canvas(buffer)
j = 0
for _ in range(len(datas) // (NUM_LABELS_X * NUM_LABELS_Y) + 1):
for u in range(0, NUM_LABELS_Y):
for i in range(0, NUM_LABELS_X):
if j < len(datas):
data = datas[j]
cb = data.barcode
desc = data.label
try:
label = self.generate_label(
ean13=cb,
description=desc,
bar_height=bar_height,
postion_text_y=position_text_y,
)
x = i * LABEL_WIDTH
y = SHEET_TOP - LABEL_HEIGHT - u * LABEL_HEIGHT
label.drawOn(p, x, y)
except AttributeError:
pass
j += 1
p.showPage()
p.save()
pdf = buffer.getvalue()
buffer.close()
return pdfSo how do A4PrinterBarcode work ?
The main concept of this class is to generate the “labels” (barcode and text) and put them into a grid pattern. So we have two function:
- generate_label generate the single “label”, one of the time
- get_pdf generate the pdf putting the “labels” in a grid pattern
If you need, this class can be used without Django, in something like a tool for terminal
This post is part of the Printing With ReportLab series
- Letterhead With ReportLab
- Django Return Pdf With Reportlab
- Django Generate Barcode With Reportlab
This post is part of the Django Tricks series
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