🔤 PDF 添加文字（使用内嵌字体）Add Text to PDF with Embedded Fonts

使用说明与常见问题How-to & FAQ

「PDF 添加文字（使用内嵌字体）」是什么？What is the Add Text to PDF with Embedded Fonts tool?

打开 PDF，在页面任意位置点击输入文字，字体直接复用 PDF 里已经嵌入的字体，新写的字与原文风格一致；可拖动位置、多页多处添加，自动检查子集字体缺字并用备用字体补齐，导出时保留原有内容。Open a PDF, click anywhere on a page and type — the new text reuses the fonts already embedded in the PDF, so it matches the original. Drag to reposition, add text on any page, get warned about characters a subset font lacks (filled in with a fallback font), and download a PDF with the original content intact.

如何使用「PDF 添加文字（使用内嵌字体）」？How do I use the Add Text to PDF with Embedded Fonts?

选择或拖入 PDF，页面下方列出文件里的全部字体（名称、类型、是否嵌入、是否子集、可用字符数）。在页面上点击要写字的位置，在弹出的输入框里输入文字；默认自动选用附近原文的字体和字号，也可在工具栏改字体、字号和颜色。拖动文字框可调整位置，可在多页添加多处文字。预览就是最终效果，确认后点「生成并下载 PDF」。Pick or drop a PDF; every font in the file is listed (name, type, embedded or not, subset or not, usable characters). Click where you want to write and type in the pop-up box; the font and size of the nearby original text are picked automatically, or change font, size and colour in the toolbar. Drag a box to move it and add text on as many pages as you like. The preview is the final result — click “Generate & download PDF” when done.

为什么有的字写不出来？什么是子集字体？Why can’t some characters be written? What is a subset font?

为了减小文件，PDF 通常只嵌入用到的字形（子集字体，字体名前带 6 个大写字母和「+」，如 ABCDEF+SimSun）。原文没出现过的字，子集里就没有。工具会逐字检查，并提示「这个字体是子集，缺少：X、Y」；缺的字默认用备用字体（西文 Helvetica、中文思源黑体，或你上传的字体）补齐，也可以选择跳过。点字体表里的「可用字符」可以查看这个字体能写哪些字。To keep files small, PDFs usually embed only the glyphs they use (a subset font, whose name starts with six capital letters and “+”, such as ABCDEF+SimSun). Characters that never appear in the original are not in the subset. The tool checks every character and warns “this font is a subset and lacks: X, Y”; by default the missing ones are drawn with a fallback font (Helvetica for Latin, Noto Sans SC for Chinese, or a font you upload), or you can skip them. Click “Characters” in the font table to see what a font can write.

真的用的是 PDF 里的字体吗？文件会变大吗？Is it really the PDF’s own font? Will the file grow?

是的。新文字直接引用 PDF 里原来的字体对象（同一个字体资源），按该字体的编码（ToUnicode / Encoding / Identity-H）写入字符代码，不会重新嵌入字体，所以文件几乎不变大。只有缺字用了备用字体时，才会额外嵌入备用字体中用到的字形。Yes. The new text references the PDF’s existing font object (the same font resource) and writes character codes in that font’s encoding (ToUnicode / Encoding / Identity-H), so no font is re-embedded and the file barely grows. Only characters filled in with the fallback font embed extra glyphs from that font.

哪些字体不能复用？Which fonts can’t be reused?

Type3 字体（由绘图指令组成）、竖排字体（-V 编码），以及没有 ToUnicode 又无法从编码推断字符的字体无法复用，会在字体表中注明原因；未嵌入的字体可以使用，但显示效果取决于阅读器的替代字体。扫描件没有字体，只能使用备用字体。Type3 fonts (drawn with PDF operators), vertical fonts (-V encodings) and fonts with neither a ToUnicode map nor an encoding the characters can be worked out from cannot be reused; the font table says why. Non-embedded fonts can be used, but their look depends on the viewer’s substitute. Scanned PDFs contain no fonts, so only the fallback font is available.

会改动或破坏原来的内容吗？Does it change the original content?

不会。原有页面内容保持不变，新文字作为独立的内容追加在页面上方。注意：已签名的 PDF 修改后数字签名会失效；加密的 PDF 需要先输入打开密码。No. The original page content is kept as is and the new text is appended on top as separate content. Note that editing a digitally signed PDF invalidates the signature, and an encrypted PDF needs its open password first.

「PDF 添加文字（使用内嵌字体）」免费吗？数据会上传吗？Is the Add Text to PDF with Embedded Fonts free? Is my data uploaded?

「PDF 添加文字（使用内嵌字体）」完全免费，无需注册或安装，手机和电脑都能用；所有处理都在你的浏览器本地完成，输入的内容和文件不会上传到服务器。The Add Text to PDF with Embedded Fonts is completely free with no sign-up or install and works on phones and desktops; everything runs locally in your browser and nothing you enter is uploaded.