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Fulfillment-Backend/barcodes/pdf/generator.py

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import os
from io import BytesIO
from typing import List
from reportlab.graphics.barcode import code128
from reportlab.lib.pagesizes import mm
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.pdfgen import canvas
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak
from constants import APP_PATH
from schemas.barcode import PdfBarcodeGenData
class PDFGenerator:
def __init__(self):
ASSETS_FOLDER = os.path.join(APP_PATH, 'assets')
FONTS_FOLDER = os.path.join(ASSETS_FOLDER, 'fonts')
FONT_FILE_PATH = os.path.join(FONTS_FOLDER, 'DejaVuSans.ttf')
self.page_width = 58 * mm
self.page_height = 40 * mm
self.number_of_spacing_pages = 2
pdfmetrics.registerFont(TTFont('DejaVuSans', FONT_FILE_PATH))
# Get standard styles and create a new style with a smaller font size
styles = getSampleStyleSheet()
self.small_style = ParagraphStyle(
'Small',
parent=styles['Normal'],
fontName='DejaVuSans', # Specify the new font
fontSize=6,
leading=7,
spaceAfter=2,
leftIndent=2,
rightIndent=2,
)
def generate_small_text(self, barcode_value, text, num_duplicates=1):
buffer = BytesIO()
# Create document with specified page size
doc = SimpleDocTemplate(
buffer,
pagesize=(self.page_width, self.page_height),
rightMargin=1 * mm,
leftMargin=1 * mm,
topMargin=1 * mm,
bottomMargin=1 * mm
)
# Create paragraph with new style
paragraph = Paragraph(text, self.small_style)
# Get the width and height of the paragraph
paragraph_width, paragraph_height = paragraph.wrap(self.page_width - 2 * mm, self.page_height)
# Create barcode
barcode_height = (self.page_height - paragraph_height * mm)
available_width = self.page_width - 2 * mm # Adjust for margins
# Approximate number of elements in a Code 128 barcode for average length
num_elements = 11 * len(barcode_value) # Rough estimate: 11 elements per character
# Calculate barWidth
bar_width = available_width / num_elements
barcode = code128.Code128(
barcode_value,
barWidth=bar_width,
barHeight=barcode_height,
humanReadable=True
)
# Function to draw barcode on canvas
def add_barcode(canvas, doc):
barcode_width = barcode.width
barcode_x = (self.page_width - barcode_width) / 2 # Center the barcode
barcode.drawOn(canvas, barcode_x, self.page_height - barcode.height - 5)
# Create list of elements to add to the document
elements = []
for _ in range(num_duplicates):
elements.append(Spacer(1, barcode_height + 2 * mm))
elements.append(paragraph)
elements.append(PageBreak())
# Build document
doc.build(elements[:-1], onFirstPage=add_barcode, onLaterPages=add_barcode) # Remove the last PageBreak
buffer.seek(0)
return buffer
# Создание документа с указанным размером страницы
def _create_doc(self, buffer):
return SimpleDocTemplate(
buffer,
pagesize=(self.page_width, self.page_height),
rightMargin=1 * mm,
leftMargin=1 * mm,
topMargin=1 * mm,
bottomMargin=1 * mm
)
def generate(self, barcodes_data: List[PdfBarcodeGenData]) -> BytesIO:
buffer = BytesIO()
# Создаем документ с указанным размером страницы
doc = self._create_doc(buffer)
# Список элементов для добавления в документ
elements = []
product_barcode_canvases = []
for barcode_data in barcodes_data:
# Создаем абзац с новым стилем
paragraph = Paragraph(barcode_data.text, self.small_style)
# Получаем ширину и высоту абзаца
paragraph_width, paragraph_height = paragraph.wrap(self.page_width - 2 * mm, self.page_height)
# Рассчитываем доступное пространство для штрихкода
human_readable_height = 6 * mm # Высота human-readable текста
space_between_text_and_barcode = 4 * mm # Отступ между текстом и штрихкодом
barcode_height = self.page_height - paragraph_height - human_readable_height - space_between_text_and_barcode - 4 * mm # Учитываем поля и отступы
# Создаем штрихкод
available_width = self.page_width - 2 * mm # Учитываем поля
# Приблизительное количество элементов в штрихкоде Code 128 для средней длины
num_elements = 11 * len(barcode_data.barcode_value) # Примерная оценка: 11 элементов на символ
# Рассчитываем ширину штриха
bar_width = available_width / num_elements
barcode = code128.Code128(
barcode_data.barcode_value,
barWidth=bar_width,
barHeight=barcode_height,
humanReadable=True
)
product_barcode_canvases.append(barcode)
# Добавление штрихкодов в список элементов документа
for _ in range(barcode_data.num_duplicates):
elements.append(paragraph)
elements.append(Spacer(1, space_between_text_and_barcode)) # Отступ между текстом и штрихкодом
elements.append(PageBreak())
# Добавление спейсеров
for _ in range(self.number_of_spacing_pages):
elements.append(PageBreak())
# Удалить последние спейсеры
elements = elements[:-2]
product_counter, product_barcodes_counter = 0, 0
# Функция для отрисовки штрихкода на canvas
def add_barcode(canvas, doc):
nonlocal product_barcodes_counter, product_counter
barcode_canvas = product_barcode_canvases[product_counter]
product_barcodes_counter += 1
# Если данная страница это спейсер, то оставить пустой
num_duplicates = barcodes_data[product_counter].num_duplicates
if product_barcodes_counter > num_duplicates:
if product_barcodes_counter >= num_duplicates + self.number_of_spacing_pages:
product_barcodes_counter = 0
product_counter += 1
return
# Отрисовка штрихкода
barcode_width = barcode_canvas.width
barcode_x = (self.page_width - barcode_width) / 2 # Центрируем штрихкод
barcode_y = human_readable_height + 2 * mm # Размещаем штрихкод снизу с учетом отступа
barcode_canvas.drawOn(canvas, barcode_x, barcode_y)
# Создаем документ
doc.build(elements[:-1], onFirstPage=add_barcode, onLaterPages=add_barcode) # Убираем последний PageBreak
buffer.seek(0)
return buffer
def generate_barcode_image(self, barcode_image_url: str, path_to_save_pdf: str):
print(type(path_to_save_pdf))
print(path_to_save_pdf)
c = canvas.Canvas(path_to_save_pdf, pagesize=(self.page_width, self.page_height))
c.drawImage(barcode_image_url, 0, 0, width=self.page_width, height=self.page_height)
c.save()