识别pdf标题并重命名pdf

此为改进版
解决了期刊名可能是最大字体的问题：
思路 识别字符串的空格＞3则为标题
另外因为标题中不能出现冒号问题，这里用中文“冒号”代替了符号“：”

import os
import PyPDF2

import fitz

def find_largest_font_sentence(pdf_path):
    largest_font_size = 0
    largest_font_sentence = ''
    maxsize=0
    # 打开PDF文件
    document = fitz.open(pdf_path)

    for page_number in range(document.page_count):
        page = document.load_page(page_number)
        blocks = page.get_text("dict")["blocks"]

        for block in blocks:
            if "lines" in block:  # 检查是否存在 lines 字段
                for line in block["lines"]:
                    for span in line["spans"]:
                        if span["size"] > largest_font_size:
                            largest_font_size = span["size"]
                            largest_font_sentence = span["text"]
        maxsize=largest_font_size
        for block in blocks:
            if "lines" in block:  # 检查是否存在 lines 字段
                for line in block["lines"]:
                    for span in line["spans"]:
                        if span["size"] ==maxsize:
                            if largest_font_sentence!=span["text"]:
                                largest_font_sentence = largest_font_sentence+' '+span["text"]

        if largest_font_sentence.count(' ')<4:
            largest_font_sentence=''
            largest_font_size=0
            for block in blocks:
                if "lines" in block:  # 检查是否存在 lines 字段
                    for line in block["lines"]:
                        for span in line["spans"]:
                            if span["size"] > largest_font_size and span["text"].count(' ')>3:
                                largest_font_size = span["size"]
                                largest_font_sentence = span["text"]
            maxsize = largest_font_size
            for block in blocks:
                if "lines" in block:  # 检查是否存在 lines 字段
                    for line in block["lines"]:
                        for span in line["spans"]:
                            if span["size"] == maxsize:
                                if largest_font_sentence != span["text"]:
                                    largest_font_sentence = largest_font_sentence + ' ' + span["text"]

    return largest_font_sentence

# 用于测试的PDF文件路径



def rename_pdfs(directory):
    for filename in os.listdir(directory):
        if filename.endswith(".pdf"):
            filepath = os.path.join(directory, filename)
            filepath=filepath.strip()
            largest_font_sentence = find_largest_font_sentence(filepath)
            title=largest_font_sentence
            if  ":" in title:
                title = title.replace(":", "冒号")
            new_filename = title.strip() + ".pdf"
            new_filepath = os.path.join(directory, new_filename)
            os.rename(filepath, new_filepath)
            print(f"Renamed {filename} to {new_filename}")


# 指定包含英文论文PDF的目录路径
pdf_directory = "PDF文件目录"


# 调用函数进行重命名
rename_pdfs(pdf_directory)