Python PDF模板添加克罗地亚语特殊字符显示异常求助

Hey there! I’ve dealt with this exact frustration before—those black boxes popping up for Croatian diacritics are such a pain. The root issue here is that the default font used by ReportLab’s canvas (Helvetica) doesn’t support Central European extended characters like č, ć, š, ž, đ. Let’s walk through the fix step by step.

Core Problem #

ReportLab’s default Helvetica font only includes basic ASCII characters. When you try to draw text with characters outside that set, the renderer can’t find matching glyphs, so it replaces them with black boxes. Your earlier attempts with UTF-8 encoding don’t help because the problem isn’t with string encoding—it’s with font support.

Step-by-Step Solution #

1. Use a Font That Supports Croatian Characters #

You need to load a TrueType (TTF) font that includes Central European glyphs. Common options include:

• Arial (preinstalled on Windows/macOS)
• Times New Roman
• Liberation Sans (open-source, cross-platform)
• DejaVu Sans (another open-source option)

First, import the necessary modules to register the font:

from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont

Then register your chosen font. You’ll need to provide the font name (for reference in your code) and the full path to the TTF file on your system:

# macOS example path for Arial
pdfmetrics.registerFont(TTFont('Arial', '/Library/Fonts/Arial.ttf'))

# Windows example path
# pdfmetrics.registerFont(TTFont('Arial', 'C:/Windows/Fonts/arial.ttf'))

# Linux example (if you have msttcorefonts installed)
# pdfmetrics.registerFont(TTFont('Arial', '/usr/share/fonts/truetype/msttcorefonts/Arial.ttf'))

2. Set the Registered Font in Your Canvas #

Before drawing text, tell the canvas to use your registered font instead of the default:

can.setFont('Arial', 12)  # 12 is the font size—adjust as needed
can.drawString(100, 100, "Kopačka")

3. Remove Unnecessary Encoding #

Your earlier attempt to encode the string with .encode('utf-8') was counterproductive—ReportLab’s drawString expects a Python Unicode string, not a byte string. Stick with the raw string like "Kopačka" and let the font handle the glyph rendering.

Full Working Example #

Here’s a complete code snippet putting it all together:

import io
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import A4
from PyPDF2 import PdfReader, PdfWriter  # Use PdfReader/PdfWriter for newer PyPDF2 versions
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont

# Register the font (update path to match your system)
pdfmetrics.registerFont(TTFont('Arial', '/Library/Fonts/Arial.ttf'))

# Create the text overlay
packet = io.BytesIO()
can = canvas.Canvas(packet, pagesize=A4)

# Set the font and draw text with Croatian diacritics
can.setFont('Arial', 12)
can.drawString(100, 100, "Kopačka")
can.drawString(100, 80, "Čačak, Šibenik, Županja, Đakovo")  # Test more characters
can.save()

# Reset packet to read from the start
packet.seek(0)
new_pdf = PdfReader(packet)

# Merge with your template PDF
template = PdfReader(open("your_template.pdf", "rb"))
output = PdfWriter()

# Merge the first page of the overlay with the first page of the template
page = template.pages[0]
page.merge_page(new_pdf.pages[0])
output.add_page(page)

# Save the final PDF
with open("output_with_diacritics.pdf", "wb") as f:
    output.write(f)

Additional Notes #

• If you don’t have access to system fonts, download an open-source font like Liberation Sans, place it in your project directory, and use a relative path (e.g., ./fonts/LiberationSans-Regular.ttf).
• For newer PyPDF2 versions, note that PdfFileReader/PdfFileWriter are deprecated—use PdfReader and PdfWriter instead (as shown in the example).
• Double-check that your font path is correct—incorrect paths will fall back to the default font, bringing back the black boxes.

Give this a try, and those Croatian diacritics should display perfectly instead of those annoying black boxes!

内容的提问来源于stack exchange，提问作者William Grey