读取 Xournal++ 中 PDF 批注的高亮信息，导出成切片截图
使用 Xournal++ 阅读 PDF 书籍，希望在阅读结束后将高亮所在区域导出成切片，以便其他软件处理
demo/import 目录中有一个使用 Xournal++ 标记的 PDF 文件，经过该软件处理后的输出结果如下图所示：
文件名含义为：{页码}-{页面内高亮区域}.png
- 只支持 Xournal++ 的高亮直线（即荧光笔直线工具，其他均不支持）
# 以 Arch Linux 为例，其他平台安装方式大同小异
sudo pacman -S graphicsmagick
git clone https://github.com/LuRenJiasWorld/Xopp-Annotation-Crop-And-Export.git
cd Xopp-Annotation-Crop-And-Export
npm install
# or pnpm install (extremely fast!)
vim src/index.js
# 编辑 exportAnnotationFromPDF 参数，分别为
# - Xopp 文件路径
# - Xournal++ 导出带批注的 PDF 文件路径
# - 导出切片截图文件路径（可以不修改）
npm run start
# or npm run cleanstart (remove last generated exports before beginning)- 读取 Xournal++ 的 Xopp 文件（Gzip 后的 XML 文件），得到高亮直线坐标信息
- 膨胀坐标，以便相邻行划线可以相交
- 使用 R树 对相邻划线进行聚类
- 计算聚类后的最小外接矩形
- 裁切并导出
- 如果软件出现 BUG，欢迎提交 Issue 讨论
- 如果你觉得代码有优化余地，欢迎提交 Pull Requests
- NaturalIntelligence/fast-xml-parser: Validate XML, Parse XML and Build XML rapidly without C/C++ based libraries and no callback.
- yakovmeister/pdf2image: A utility for converting pdf to image and base64 format.
- mourner/rbush: RBush — a high-performance JavaScript R-tree-based 2D spatial index for points and rectangles
- lovell/sharp: High performance Node.js image processing, the fastest module to resize JPEG, PNG, WebP, AVIF and TIFF images. Uses the libvips library.
MIT License
MIT License
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