[Request] Support rendering existing `usvg::Tree`

[sww1235]

Support loading SVG images directly from usvg::Tree that is already in memory.

Is your feature request related to a problem? Please describe.
I cannot render SVG images in egui with an already existing usvg::Tree.

Describe the solution you'd like
Some additional method on the svg_loader in egui_extras named something like from_tree() that would accept a usvg::Tree. Not quite sure how this would work, as I am not familiar with the internals of the library. Would be nice to not have to specify a URI in this function as it already knows what datatype is incoming.

Describe alternatives you've considered
My current solution is to use egui::widgets::Image::from_bytes() and convert the tree to a bytes array using tree.to_string().into_bytes() which introduces several additional conversion steps.

Additional context
I am building a library that uses usvg::Tree internally to parse custom data out of SVGs. As I already have the SVG parsed into a tree, it would be ideal to pass that directly to rendering code without having to go through converting to string, then bytes, then reparsing the SVG.

This is partially related to #7797.

[Its-Just-Nans]

Hi

You can just render your svg to an image and display the image no?

[sww1235]

You can just render your svg to an image and display the image no?

What do you mean? Create a raster image to display? I would rather not to avoid scaling and DPI issues which is the whole reason i am using SVG in the first place.

What I have works and I get the expected output, but requires several additional conversion steps that would be avoided if I could pass a usvg::Tree directly to the load() function or equivalent.

[Its-Just-Nans]

In any case your svg will be rendered ?!

I think I understand, you want a wrapper like load_svg_bytes_with_size (crates/egui_extras/src/image.rs).
So you can just do the same as load_svg_bytes_with_size ?!

[sww1235]

Basically yes. See how the svg_bytes array is parsed into a usvg::Tree on line line 74.

What I am asking for, is essentially a modified version of the load_svg_bytes_with_size function that would accept a usvg::Tree instead of a &[u8].

Do you see how there are several extraneous conversions between strings, byte arrays and usvg::Trees in the current approach

[oscargus]

Shouldn't it just be to factor everything below that line out to a separate function and then call it there and provide it as a public function?