feat: add pdfpc-file metadata in typst directly

[OrangeX4]

Many thanks for Polylux anyway, it is very cool. But I think it would be nice to have the ability to export pdfpc file without polylux2pdfpc.

A lot of work has been done in #83 and #84 , but too many files have been modified. I just come up with a simpler method. I add a locate and query in pdfpc.config() function, so you just add pdfpc.config() in your slide source file to enable this feature.

You can export pdfpc file without polylux2pdfpc simply by:

typst query --root . example.typ --field value --one "<pdfpc-file>" > example.pdfpc

https://typst.app/project/rzIE9aLpKytQUQNn8SSRrP

This PR is significant for tools other than pdfpc, just like Typst Preview, which already has a slide mode.

With this feature, Typst Preview can implement better navigation and presenter view, which is much more convenient than pdfpc because you have a hard time installing pdfpc on Windows #106 , and Typst Preview has animated GIFs support that pdfpc doesn't have. Enter-tainer/typst-preview#191 Enter-tainer/typst-preview#192

It's also a good way to achieve #122 .

@andreasKroepelin If you have spare time, could you please take a look at this? Many thanks!

[drupol]

@andreasKroepelin I really like this idea, this could be a good idea to avoid having a dependency to an external program to extract the metadata. What do you think of it?

[andreasKroepelin]

@OrangeX4 @drupol Sorry, I never reacted on this PR. I think the change to Polylux' code is okay but I don't like the user interface of having to call this complicated typst query command. I think "use this tool polylux2pdfpc" is an easier to follow advice for users.

[OrangeX4]

Thanks for reply. I prefer the typst query command, even though it's a bit more complicated. I think that this command is a low-frequency copy-and-paste command, so it won't be annoying too much. However, keeping polylux2pdfpc as an option also make sense, providing users with two choices.

[drupol]

I do prefer having less complexity and fewer dependencies too, as long as the command to extract the data is correctly documented, it's not an issue.

[yohhaan]

+1 for fewer dependencies and directly being able to generate the .pdfpc file with a typst query command.
Thanks @OrangeX4 for this added code snippet that essentially allows to just do that.

My suggested changes remove the use of locate and replace it with context to make it work with newer Typst versions.