From ec1faa60d95d98afe82ac1ba2d2226db0f498402 Mon Sep 17 00:00:00 2001
From: ytqh <yutianqiuhao@gmail.com>
Date: Sat, 5 Apr 2025 22:19:56 +0800
Subject: [PATCH] fix chinese

---
 .../inner_tools/markdown_to_pdf.py            | 89 ++++++++++++-------
 1 file changed, 55 insertions(+), 34 deletions(-)

diff --git a/api/controllers/inner_tools/markdown_to_pdf.py b/api/controllers/inner_tools/markdown_to_pdf.py
index 6f8259c508..67d0abaa90 100644
--- a/api/controllers/inner_tools/markdown_to_pdf.py
+++ b/api/controllers/inner_tools/markdown_to_pdf.py
@@ -10,8 +10,13 @@ from core.tools.tool_file_manager import ToolFileManager
 from flask import Response, jsonify, request
 from flask_restful import Resource  # type: ignore
 from models.account import Tenant
+from reportlab.lib.enums import TA_LEFT
 from reportlab.lib.pagesizes import letter
+from reportlab.lib.styles import ParagraphStyle, getSampleStyleSheet
+from reportlab.pdfbase import pdfmetrics
+from reportlab.pdfbase.ttfonts import TTFont
 from reportlab.pdfgen import canvas
+from reportlab.platypus import Paragraph, SimpleDocTemplate
 
 
 class MarkdownToPDFApi(Resource):
@@ -58,52 +63,68 @@ class MarkdownToPDFApi(Resource):
 
     def _generate_pdf_binary(self, markdown_text: str, title: str) -> Tuple[bytes, str]:
         """Generate PDF from markdown text and return the binary data and filename"""
-        # Convert markdown to HTML (for potential future enhancement)
-        html_content = markdown.markdown(markdown_text, extensions=['extra'])
 
-        # Create PDF using reportlab
         buffer = io.BytesIO()
-        pdf = canvas.Canvas(buffer, pagesize=letter)
 
-        # Add title
-        pdf.setFont("Helvetica-Bold", 16)
-        pdf.drawString(72, 760, title)
+        # Create a PDF document with platypus for better CJK text handling
+        doc = SimpleDocTemplate(buffer, pagesize=letter, rightMargin=72, leftMargin=72, topMargin=72, bottomMargin=72)
+
+        # Register Noto Sans CJK font which should be available in the Docker container
+        # (as specified in the Dockerfile: apt-get install -y fonts-noto-cjk)
+        try:
+            pdfmetrics.registerFont(TTFont('NotoSansCJK', '/usr/share/fonts/truetype/noto/NotoSansCJK-Regular.ttc'))
+            cjk_font_name = 'NotoSansCJK'
+        except:
+            # Fallback to DejaVuSans which has decent Unicode support
+            try:
+                pdfmetrics.registerFont(TTFont('DejaVuSans', '/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf'))
+                cjk_font_name = 'DejaVuSans'
+            except:
+                # If neither font is available, fall back to the default
+                cjk_font_name = 'Helvetica'
+
+        # Create styles for our document
+        styles = getSampleStyleSheet()
+
+        # Create a custom style for title with CJK font support
+        title_style = ParagraphStyle(
+            'Title', parent=styles['Title'], fontName=cjk_font_name, fontSize=16, alignment=TA_LEFT
+        )
+
+        # Create a custom style for headings with CJK font support
+        h1_style = ParagraphStyle('Heading1', parent=styles['Heading1'], fontName=cjk_font_name, fontSize=14)
+
+        h2_style = ParagraphStyle('Heading2', parent=styles['Heading2'], fontName=cjk_font_name, fontSize=13)
 
-        # Add markdown content
-        pdf.setFont("Helvetica", 12)
-        y_position = 730
+        h3_style = ParagraphStyle('Heading3', parent=styles['Heading3'], fontName=cjk_font_name, fontSize=12)
 
-        # Simple text rendering - each line as a separate line in the PDF
+        # Create a custom style for normal text with CJK font support
+        normal_style = ParagraphStyle(
+            'Normal', parent=styles['Normal'], fontName=cjk_font_name, fontSize=12, leading=14  # Line spacing
+        )
+
+        # Create a list of flowables for our document
+        flowables = []
+
+        # Add title
+        flowables.append(Paragraph(title, title_style))
+        flowables.append(Paragraph("<br/>", normal_style))  # Add some space
+
+        # Process each line of markdown and add appropriate paragraphs
         for line in markdown_text.split('\n'):
             if line.startswith('# '):  # H1 heading
-                pdf.setFont("Helvetica-Bold", 14)
-                pdf.drawString(72, y_position, line[2:])
-                y_position -= 20
-                pdf.setFont("Helvetica", 12)
+                flowables.append(Paragraph(line[2:], h1_style))
             elif line.startswith('## '):  # H2 heading
-                pdf.setFont("Helvetica-Bold", 13)
-                pdf.drawString(72, y_position, line[3:])
-                y_position -= 18
-                pdf.setFont("Helvetica", 12)
+                flowables.append(Paragraph(line[3:], h2_style))
             elif line.startswith('### '):  # H3 heading
-                pdf.setFont("Helvetica-Bold", 12)
-                pdf.drawString(72, y_position, line[4:])
-                y_position -= 16
-                pdf.setFont("Helvetica", 12)
+                flowables.append(Paragraph(line[4:], h3_style))
             elif line.strip() == '':  # Empty line
-                y_position -= 12
+                flowables.append(Paragraph("<br/>", normal_style))
             else:  # Regular text
-                pdf.drawString(72, y_position, line)
-                y_position -= 14
-
-            # Check if we need a new page
-            if y_position < 72:
-                pdf.showPage()
-                y_position = 760
-                pdf.setFont("Helvetica", 12)
+                flowables.append(Paragraph(line, normal_style))
 
-        # Save the PDF
-        pdf.save()
+        # Build the PDF
+        doc.build(flowables)
         buffer.seek(0)
 
         # Generate a filename based on the title