如何精确定位一个PDF网页链接的矩形坐标？

import fitz  # PyMuPDF

def extract_link_coordinates(pdf_path):
    # 打开PDF文件
    doc = fitz.open(pdf_path)
    link_coordinates = []

    for page_num in range(len(doc)):
        page = doc.load_page(page_num)
        annots = page.annots()

        for annot in annots:
            if annot.type[0] == 8:  # 8表示链接注释
                quad_points = annot.vertices
                for i in range(0, len(quad_points), 4):
                    x1, y1, x2, y2 = quad_points[i], quad_points[i+1], quad_points[i+2], quad_points[i+3]
                    link_coordinates.append((x1, y1, x2, y2))

    return link_coordinates

# 示例使用
pdf_path = 'example.pdf'
coordinates = extract_link_coordinates(pdf_path)
for coord in coordinates:
    print(f"Link coordinates: {coord}")