Subset a name-keyed CFF font without making it CID-keyed

未关闭
  • 哪里不对？
#39 0 条评论 0 个 reaction 已指派 0 人 在 GitHub 查看

还没有人认领这个 Issue。

评估

难度
5/5
预计耗时
一周以上
新手友好度
45/100
Issue 类型
功能
描述清晰度
基本清楚
活跃度
活跃
技术栈
rust
领域
backend

调研方向

Start by reading the crate's CFF subsetting implementation and its tests; the issue does not name specific files or entry points. Check how SID-keyed fonts are converted to CID-keyed fonts, then assess how a name-keyed subset could retain glyph SIDs, strings, and a custom encoding. Done means an option preserves name-keyed fonts and tests verify that kept glyph codes still resolve by name.

由索引模型根据 Issue 内容生成。

描述

subset converts SID-keyed CFF fonts to CID-keyed ones. That is right for new PDF output, but a PDF that already embeds a Type1C program for a simple font (/Subtype /Type1 with /FontFile3 /Subtype /Type1C) maps its one-byte codes to glyphs through glyph names (the font's /Encoding and /Differences, else the CFF's built-in encoding). A CID-keyed subset loses the names, so readers fall back to .notdef.

Would an option to keep a name-keyed font name-keyed (a charset with the kept glyphs' SIDs and the string INDEX, and a custom encoding for the kept codes) fit the crate's scope? It is the other half of subsetting fonts that existing PDFs embed; most CFF programs in PDFs are name-keyed Type1C. I can send a PR with tests if the shape is acceptable.

🤖 Generated with Claude Code

主要语言
Rust
星标
61
派生
16
30 天内没有已合并 PR

环境准备

这个项目没有提供开发容器、Dockerfile 或贡献指南，环境需要你自己搭建：先看它的 README，通用步骤见我们的新手贡献指南。

从这里开始

  1. 先读完整个 Issue，再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库，在一个分支上完成修改。
  4. 提交 Pull Request，并在描述里引用这个 Issue 编号。

typst/subsetter 的其他 Issue

查看 typst/subsetter 的全部 Issue

相似的 Issue

更多 Rust Issue

把新 issue 发到你的邮箱

精选适合新手参与的 GitHub issue 摘要。