Support resvg as alternative to rsvg-convert for SVG rendering

[cderv]

Installing rsvg-convert on Windows can be challenging for users, requiring either manual binary installation or complex package manager setup. This affects workflows that convert SVG to PDF/LaTeX output, including mermaid diagrams with mermaid-format: svg.

resvg (https://github.com/linebender/resvg) is a modern Rust-based SVG rendering library with better cross-platform support. It provides pre-built binaries for all platforms and is available through Windows package managers (scoop, winget), making installation significantly easier for Windows users.

We could add resvg as an alternative SVG converter alongside rsvg-convert and Inkscape. The conversion pipeline in src/resources/filters/quarto-post/pdf-images.lua already handles rsvg-convert and has infrastructure for tool detection.

quarto-cli/src/resources/filters/quarto-post/pdf-images.lua

Lines 28 to 61 in c9008d7

	local function convert_svg(image)
	-- If the src is pointing to a local file that is an svg, process it
	local ext = select(2, pandoc.path.split_extension(image.src))
	if ext ~= '.svg' then
	return nil
	end
	if not option("use-rsvg-convert", true) then
	local stem = pandoc.path.split_extension(image.src)
	local output = stem .. '.pdf'
	if not _quarto.file.exists(output) then
	warn("Skipping SVG conversion for " .. path .. " because use-rsvg-convert is false, but required PDF file does not exist: " .. output)
	else
	image.src = output
	return image
	end
	end
	local converted_path, must_clean = call_rsvg_convert(image.src)
	if converted_path == nil then
	return nil
	end
	local contents = _quarto.file.read(converted_path)
	assert(contents ~= nil)
	local relative_path = pandoc.path.make_relative(converted_path, '.')
	-- add to media bag and remove the converted file
	pandoc.mediabag.insert(relative_path, 'application/pdf', contents)
	if must_clean then
	_quarto.file.remove(relative_path)
	end
	image.src = relative_path
	return image
	end

We could implement this similar to the existing use-rsvg-convert option, perhaps with a more general svg-converter option that accepts resvg, rsvg-convert, or inkscape, with automatic fallback to whichever tool is available.

This came up while investigating #13661, where better SVG tooling options would help Windows users. Directly addresses the request in #1144 for specifying alternative SVG conversion tools.

[cderv]

Though it only convers to PNG... not PDF
They consider out of scope: linebender/resvg#65

So it can't be used for PDF images right now. Too bad.

[jkrumbiegel]

What about using Typst for that? You already bundle it and it sort of contains SVG to PDF conversion machinery. Maybe with something like

#set page(width: auto, height: auto, margin: 0pt)

#image("some_figure.svg")

and then typst compile input.typ some_figure.pdf

[cderv]

Really interesting idea ! I haven't thought of that. 🤔 Thanks !