马一丁
251 lines
7.0 KiB
Python
251 lines
7.0 KiB
Python
"""
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PDF渲染器 - 使用WeasyPrint从HTML生成PDF
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支持完整的CSS样式和中文字体
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"""
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from __future__ import annotations
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import base64
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from pathlib import Path
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from typing import Any, Dict
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from datetime import datetime
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from loguru import logger
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try:
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from weasyprint import HTML, CSS
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from weasyprint.text.fonts import FontConfiguration
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WEASYPRINT_AVAILABLE = True
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except ImportError:
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WEASYPRINT_AVAILABLE = False
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logger.warning("WeasyPrint未安装，PDF导出功能将不可用")
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from .html_renderer import HTMLRenderer
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from .pdf_layout_optimizer import PDFLayoutOptimizer, PDFLayoutConfig
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class PDFRenderer:
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"""
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基于WeasyPrint的PDF渲染器
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- 直接从HTML生成PDF，保留所有CSS样式
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- 完美支持中文字体
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- 自动处理分页和布局
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"""
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def __init__(
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self,
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config: Dict[str, Any] | None = None,
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layout_optimizer: PDFLayoutOptimizer | None = None
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):
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"""
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初始化PDF渲染器
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参数:
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config: 渲染器配置
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layout_optimizer: PDF布局优化器（可选）
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"""
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self.config = config or {}
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self.html_renderer = HTMLRenderer(config)
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self.layout_optimizer = layout_optimizer or PDFLayoutOptimizer()
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if not WEASYPRINT_AVAILABLE:
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raise RuntimeError("WeasyPrint未安装，请运行: pip install weasyprint")
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@staticmethod
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def _get_font_path() -> Path:
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"""获取字体文件路径"""
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# 优先使用完整字体以确保字符覆盖
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fonts_dir = Path(__file__).parent / "assets" / "fonts"
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# 检查完整字体
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full_font = fonts_dir / "SourceHanSerifSC-Medium.otf"
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if full_font.exists():
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logger.info(f"使用完整字体: {full_font}")
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return full_font
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# 检查TTF子集字体
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subset_ttf = fonts_dir / "SourceHanSerifSC-Medium-Subset.ttf"
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if subset_ttf.exists():
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logger.info(f"使用TTF子集字体: {subset_ttf}")
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return subset_ttf
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# 检查OTF子集字体
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subset_otf = fonts_dir / "SourceHanSerifSC-Medium-Subset.otf"
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if subset_otf.exists():
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logger.info(f"使用OTF子集字体: {subset_otf}")
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return subset_otf
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raise FileNotFoundError(f"未找到字体文件，请检查 {fonts_dir} 目录")
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def _get_pdf_html(
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self,
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document_ir: Dict[str, Any],
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optimize_layout: bool = True
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) -> str:
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"""
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生成适用于PDF的HTML内容
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- 移除交互式元素（按钮、导航等）
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- 添加PDF专用样式
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- 嵌入字体文件
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- 应用布局优化
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参数:
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document_ir: Document IR数据
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optimize_layout: 是否启用布局优化
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返回:
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str: 优化后的HTML内容
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"""
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# 如果启用布局优化，先分析文档并生成优化配置
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if optimize_layout:
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logger.info("启用PDF布局优化...")
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layout_config = self.layout_optimizer.optimize_for_document(document_ir)
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# 保存优化日志
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log_dir = Path('logs/pdf_layouts')
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log_dir.mkdir(parents=True, exist_ok=True)
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log_file = log_dir / f"layout_{datetime.now().strftime('%Y%m%d_%H%M%S')}.json"
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# 保存配置和优化日志
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optimization_log = self.layout_optimizer._log_optimization(
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self.layout_optimizer._analyze_document(document_ir),
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layout_config
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)
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self.layout_optimizer.config = layout_config
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self.layout_optimizer.save_config(log_file, optimization_log)
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else:
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layout_config = self.layout_optimizer.config
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# 使用HTML渲染器生成基础HTML
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html = self.html_renderer.render(document_ir)
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# 获取字体路径并转换为base64（用于嵌入）
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font_path = self._get_font_path()
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font_data = font_path.read_bytes()
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font_base64 = base64.b64encode(font_data).decode('ascii')
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# 判断字体格式
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font_format = 'opentype' if font_path.suffix == '.otf' else 'truetype'
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# 生成优化后的CSS
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optimized_css = self.layout_optimizer.generate_pdf_css()
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# 添加PDF专用CSS
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pdf_css = f"""
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<style>
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/* PDF专用字体嵌入 */
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@font-face {{
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font-family: 'SourceHanSerif';
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src: url(data:font/{font_format};base64,{font_base64}) format('{font_format}');
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font-weight: normal;
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font-style: normal;
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}}
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/* 强制所有文本使用思源宋体 */
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body, h1, h2, h3, h4, h5, h6, p, li, td, th, div, span {{
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font-family: 'SourceHanSerif', serif !important;
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}}
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/* PDF专用样式调整 */
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.report-header {{
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display: none !important;
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}}
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.no-print {{
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display: none !important;
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}}
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body {{
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background: white !important;
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}}
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/* 隐藏图表canvas，显示fallback表格 */
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.chart-container {{
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display: none !important;
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}}
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.chart-fallback {{
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display: block !important;
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}}
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{optimized_css}
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</style>
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"""
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# 在</head>前插入PDF专用CSS
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html = html.replace('</head>', f'{pdf_css}\n</head>')
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return html
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def render_to_pdf(
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self,
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document_ir: Dict[str, Any],
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output_path: str | Path,
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optimize_layout: bool = True
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) -> Path:
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"""
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将Document IR渲染为PDF文件
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参数:
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document_ir: Document IR数据
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output_path: PDF输出路径
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optimize_layout: 是否启用布局优化（默认True）
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返回:
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Path: 生成的PDF文件路径
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"""
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output_path = Path(output_path)
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logger.info(f"开始生成PDF: {output_path}")
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# 生成HTML内容
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html_content = self._get_pdf_html(document_ir, optimize_layout)
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# 配置字体
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font_config = FontConfiguration()
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# 从HTML字符串创建WeasyPrint HTML对象
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html_doc = HTML(string=html_content, base_url=str(Path.cwd()))
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# 生成PDF
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try:
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html_doc.write_pdf(
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output_path,
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font_config=font_config,
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presentational_hints=True # 保留HTML的呈现提示
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)
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logger.info(f"✓ PDF生成成功: {output_path}")
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return output_path
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except Exception as e:
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logger.error(f"PDF生成失败: {e}")
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raise
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def render_to_bytes(
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self,
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document_ir: Dict[str, Any],
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optimize_layout: bool = True
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) -> bytes:
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"""
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将Document IR渲染为PDF字节流
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参数:
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document_ir: Document IR数据
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optimize_layout: 是否启用布局优化（默认True）
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返回:
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bytes: PDF文件的字节内容
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"""
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html_content = self._get_pdf_html(document_ir, optimize_layout)
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font_config = FontConfiguration()
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html_doc = HTML(string=html_content, base_url=str(Path.cwd()))
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return html_doc.write_pdf(
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font_config=font_config,
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presentational_hints=True
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)
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__all__ = ["PDFRenderer"]
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