Typst writer: add #box around image to make it inline.

[jgm]

An #image by itself in typst is a block-level element. To force images to be inline (as they are in pandoc), we need to add a box with an explicit width. When a width is not given in image attributes, we compute one from the image itself, when possible.

Closes #9104, supersedes #9105.

[cscheid]

As far as typst is concerned, I think it's enough to provide either of width or height. It looks from my reading of the code that the logic around imageSize depends only on the presence of width. If that's true, then pandoc would compute and provide width in the case that only height appears in the document.

Assuming I'm right, I think this is not ideal. I think the imageSize logic should be triggered only if neither of width and height is provided.

[jgm]

ok, I've made a small change, see how that looks

[cscheid]

I think that works.

It took me a bit because my non-Haskell brain has a hard time reading the block inside the case statement width' <- case lookup "width" kvs... and accepting it will not be evaluated if the other case statement matches (_, Just h). But I think it all works out correctly. Thank you!

[jgm]

No, your instinct was right, the code isn't right. I'll fix.

[jgm]

I think this is cleaner, but I've been writing in haste, so it needs a close look and testing.

[cscheid]

Yes - this looks symmetric wrt exchanging width and height, which makes me think it's more obviously right.