Typst Writer Wrongly Escapes Image Paths

[ljrk0]

Explain the problem.
When a source file references an external file (in this case an image), Pandoc converts the path to an URI, escaping ' ' with '%20' and so on. Typst expects a "plain" path and thus chokes on the provided URIs.

Given the following mwe.md Markdown file next to a foo bar.png image:

![](foo bar.png)

Then rendering the file to PDF produces the following error, despite foo bar.png being available:

$ pandoc --pdf-engine=typst mwe.md -o mwe.pdf
error: file not found (searched at /private/tmp/mwe/foo%20bar.png)
   ┌─ toPdfViaTempFile37815-0.html:97:40
   │
97 │ #box(width: 3.8528428093645486pt, image("foo%20bar.png"))
   │                                         ^^^^^^^^^^^^^^^

Error producing PDF.

Unescaping the URI characters fixes the issue.

Pandoc version?

$ pandoc --version
pandoc 3.1.11
Features: +server +lua
Scripting engine: Lua 5.4
User data directory: /Users/janis.koenig/.local/share/pandoc
Copyright (C) 2006-2023 John MacFarlane. Web: https://pandoc.org
This is free software; see the source for copying conditions. There is no
warranty, not even for merchantability or fitness for a particular purpose.

Installed via Nix on macOS, but I verified with the main branch in the source code. Compare the following for the Typst Writer:

      let coreImage = "image" <> parens (doubleQuoted src)

with the version for LaTeX

      source' = if isURI source
                   then source
                   else T.pack $ unEscapeString $ T.unpack source

which uses Network.URI (unEscapeString) to remove the URI characters again.

Fix
I currently don't have a Haskell environment here, but I suspect something like this should fix the issue:

+       let src' = if isURI src
+                     then src
+                     else T.pack $ unEscapeString $ T.unpack src
        let coreImage = "image" <> parens (doubleQuoted src')