✂️ PDF 自动裁白边（pdfcrop 在线版）PDF Auto Crop (Online pdfcrop)
像 pdfcrop 一样自动检测 PDF 每页内容的边界并裁掉多余白边，可设置保留边距（pt），按每页单独、全部页统一或奇偶页分别裁剪；只修改 CropBox/MediaBox，文字和矢量图保持原样不失真，适合论文插图、matplotlib 导出图和扫描讲义。Like pdfcrop: detect the content bounds on every page and trim the white margins, with an adjustable margin in pt, per page, one box for all pages or separate odd/even boxes. Only the CropBox/MediaBox change, so text and vectors stay sharp — ideal for paper figures, matplotlib exports and handouts.
使用说明与常见问题How-to & FAQ
「PDF 自动裁白边（pdfcrop 在线版）」是什么？What is the PDF Auto Crop (Online pdfcrop)?
像 pdfcrop 一样自动检测 PDF 每页内容的边界并裁掉多余白边，可设置保留边距（pt），按每页单独、全部页统一或奇偶页分别裁剪；只修改 CropBox/MediaBox，文字和矢量图保持原样不失真，适合论文插图、matplotlib 导出图和扫描讲义。Like pdfcrop: detect the content bounds on every page and trim the white margins, with an adjustable margin in pt, per page, one box for all pages or separate odd/even boxes. Only the CropBox/MediaBox change, so text and vectors stay sharp — ideal for paper figures, matplotlib exports and handouts.
如何使用「PDF 自动裁白边（pdfcrop 在线版）」？How do I use the PDF Auto Crop (Online pdfcrop)?
拖入 PDF，工具会渲染每一页并找出内容边界（红框为裁剪区域）。调整“保留边距”和裁剪模式后点“裁剪并下载”。插图通常选“每页单独”；需要整份文档页面大小一致时选“所有页统一”。Drop a PDF; each page is rendered and the content box (red) detected. Adjust the margin and mode, then press Crop & download. Use per-page for figures and one box for all pages when the document needs a uniform size.
裁剪后文件会变模糊吗？Will the cropped file be blurry?
不会。工具只改变 PDF 的页面框（CropBox/MediaBox），不重新渲染内容，文字和矢量图保持原来的清晰度，文件大小基本不变。No. Only the page boxes change; nothing is re-rendered, so text and vector art stay sharp and the size barely changes.
和 pdfcrop 命令行的结果一样吗？Is it the same as command-line pdfcrop?
原理相同：先找出非白色内容的边界再设置页面框。pdfcrop 用 Ghostscript 计算边界，本工具按 2 倍分辨率渲染计算，误差约 0.5pt，可通过边距补偿。Same idea — find the non-white bounds, then set the page box. pdfcrop uses Ghostscript bbox; this renders at 2× resolution, accurate to about 0.5 pt, which the margin covers.
浅灰色背景会被当成内容吗？Is a light grey background treated as content?
可以调节“白色容差”：数值越大，越多接近白色的像素会被当作空白。Adjust the white tolerance — higher values treat more near-white pixels as blank.
「PDF 自动裁白边（pdfcrop 在线版）」免费吗？文件会上传吗？Is the PDF Auto Crop (Online pdfcrop) free? Are my files uploaded?
「PDF 自动裁白边（pdfcrop 在线版）」完全免费，无需注册。文件只在你的浏览器里读取和处理，不会上传到任何服务器，关闭页面后不留痕迹，适合处理未发表的稿件。The PDF Auto Crop (Online pdfcrop) is free with no sign-up. Files are read and processed only in your browser, never uploaded to any server, and nothing is kept after you close the page — safe for unpublished manuscripts.