如何使用Python将PPT转PDF时正确提取并嵌入图片？

以下代码是一个Python函数，接收PowerPoint文件（ppt_file），借助多个第三方库和Python内置模块将其转换为PDF文件。以下是该代码的分步执行说明：

• 使用tempfile模块创建带.pptx扩展名的临时文件，将上传的ppt_file保存到该临时文件中。
• 再次使用tempfile模块创建带.pdf扩展名的临时文件。
• 使用python-pptx库读取第一步创建的临时文件中的PowerPoint文件。
• 使用reportlab库创建新的PDF输出文件。
• 针对PowerPoint中的每张幻灯片，计算幻灯片尺寸，并使用reportlab的landscape()或portrait()函数设置PDF画布大小。
• 将幻灯片内容提取为HTML，再使用reportlab函数绘制到PDF画布上。
• 如果幻灯片包含图片，使用Pillow库将图片转换为PNG文件并绘制到PDF画布上。
• 处理完所有幻灯片后，将PDF文件保存到第二步创建的临时文件中。
• 将临时PDF文件读取到BytesIO对象中，通过send_file以Flask响应形式返回。
• 最后使用os.unlink删除临时文件。

该函数如下：

import io
import os
import tempfile
from pptx import Presentation
from reportlab.lib.pagesizes import landscape, portrait
from reportlab.pdfgen import canvas
from flask import send_file
import imgkit
from PIL import Image

def ppt_to_pdf(ppt_file):
    # Save the uploaded file to a temporary file
    with tempfile.NamedTemporaryFile(delete=False, suffix=".pptx") as temp_ppt_file:
        ppt_file.save(temp_ppt_file.name)
        temp_ppt_file.close()

    # Create a temporary PDF file
    with tempfile.NamedTemporaryFile(delete=False, suffix=".pdf") as temp_pdf_file:
        temp_pdf_file.close()

    # Read the PowerPoint file
    prs = Presentation(temp_ppt_file.name)

    # Create a PDF file using reportlab
    pdf = canvas.Canvas(temp_pdf_file.name)

    for slide in prs.slides:
        slide_width = prs.slide_width.pt
        slide_height = prs.slide_height.pt

        # Set the page size based on the slide dimensions
        if slide_width > slide_height:
            pdf.setPageSize(landscape((slide_width, slide_height)))
        else:
            pdf.setPageSize(portrait((slide_width, slide_height)))

        # Extract slide content as HTML
        slide_html = "<html><body>"
        for shape in slide.shapes:
            if shape.has_text_frame:
                slide_html += f"<p>{shape.text}</p>"
            elif shape.shape_type == 13:  # Picture
                with tempfile.NamedTemporaryFile(delete=False, suffix=".png") as temp_image_file:
                    temp_image_file.write(shape.image.blob)
                    temp_image_file.close()

                img = Image.open(temp_image_file.name)

                # Calculate the position and size of the image on the slide
                left = shape.left.pt
                top = shape.top.pt
                width = shape.width.pt
                height = shape.height.pt

                # Draw the image on the PDF canvas
                pdf.drawImage(temp_image_file.name, left,
                              top, width=width, height=height)

                # Clean up the temporary image file
                os.unlink(temp_image_file.name)

        slide_html += "</body></html>"

        # Convert slide content to an image using imgkit
        slide_image = imgkit.from_string(
            slide_html, False, {"width": int(slide_width), "height": int(slide_height)})

        # Save the slide image to a temporary file
        with tempfile.NamedTemporaryFile(delete=False, suffix=".png") as temp_image_file:
            temp_image_file.write(slide_image)
            temp_image_file.close()

        # Draw the slide image on the PDF canvas
        pdf.drawImage(temp_image_file.name, 0, 0,
                      width=slide_width, height=slide_height)

        # Clean up the temporary image file
        os.unlink(temp_image_file.name)

        # Move to the next page
        pdf.showPage()

    pdf.save()

    # Read the temporary PDF file into a BytesIO object
    final_pdf = io.BytesIO()
    with open(temp_pdf_file.name, 'rb') as f:
        final_pdf.write(f.read())
    final_pdf.seek(0)

    # Clean up the temporary files
    os.unlink(temp_ppt_file.name)
    os.unlink(temp_pdf_file.name)

    # Return the PDF file as a Flask response
    return send_file(final_pdf, download_name='output.pdf',
                     as_attachment=True, mimetype='application/pdf')

期望该函数能返回PPT文件对应的PDF版本。

内容的提问来源于stack exchange，提问作者falfalaye GPT