How to read or import SVG images into Matlab?

I have a SVG image produced by Matlab, which contains an image and some lines on it. Now I need to read them back into Matlab. There are several solutions on the FileExchange, but all of them don't work.

[DGM]

As far as I know, none of the FEX tools provide full support for the various types of objects that can be in an SVG file. I could be mistaken, but I'm not going to test everything again just yet.

I also have to assume that if you created the SVG from MATLAB, that you did so by saving a copy of a figure. If that's the case, there's a good chance that it indeed is full of things that none of the FEX tools support, but we would have to actually see the SVG to know what's in it.

That said, if you're trying to work on an SVG of a figure, the obvious question is why. If you have a raster image with lines on it, then this is probably an unnecessarily problematic workflow that can be avoided. Again, it depends what's in the image, if/why you need to transport it as SVG, and what the end use requires. We don't know what that is yet.

[Ming Li]

Thank you for your quick response.

I am involved in an international collaborative research project. We prefer to discuss our results via SVG format figures. There are several advantages of using SVG files, such as check them in the browser, or change them in Microsoft Office easily. Recently I got a batch of SVG figures generated by MATLAB that were sent to me by a collaborator, I need to integrate them in my presentation slices with some modifications. However, that's a lot of work. If I could read them back into matlab, I can process them easily. Of course, I could ask the SVG creator to modify them, but that's inconvenient for everyone.

For my SVG examples, please see the attached svgExample.zip

Thanks again!

[DGM]

I just took a quick look at what's on the FEX. Maybe I missed some, but I see three SVG loading tools:

loadsvg() from #72225

• seems to load most sorts of path objects (polylines or curves)
• all paths are reduced to polylines by the user-specified decimation

loadSVG() from #66554

• appears to rely on the file having been written by a specific application?
• looks like it can only handle some polylines/polygons
• dumps unhandled errors or java exceptions on every file i've fed it except for two cases:
• 1: the provided test files
• 2: cases where it encounters a bezier and errors out cleanly

readSVG() from GP Toolbox #49692

• can't seem to follow some filenames/paths due to the way unix find is used
• supposedly handles bezier curves, but I seem to only get the vertex list
• supposedly returns stroke color, but I haven't observed that either

So you have three tools which can -- to varying degree -- read path objects. None of them can read other types of objects from the file (e.g. rectangles, ellipses, text, or embedded raster data), nor can they preserve any of those objects properties (e.g. color, fill, relative position or applied transformations).

While it's possible to get one or two particular things from an SVG file in a direct manner (it's just a bunch of XML), I don't know of any existing tools. Thinking ahead, it's not clear what form that information would take in the MATLAB workspace, or how it would be practically manipulated. For example, should everything in the SVG be converted into hg objects, or do we need to come up with some new class/classes?

Reading the file is just one challenge, where what you need is an entire set of tools that would facilitate the workflow you're describing. I don't think anybody has that for MATLAB.

If all you need to do is make a few modifications, can those be done in an editor like Inkscape or something? I don't know what level of functionality Office has in that regard.

[Ming Li]

Thank you DMG,

I respectfully suggest that MATLAB consider adding robust support for loading and reading SVG files in future releases. As a passionate user of both MATLAB and the SVG file format, I firmly believe that this enhancement would greatly benefit a growing community of users.

[DGM]

I wouldn't object to that. I like SVG and the idea of promoting clean, lossless graphics work. That said, implementation would be quite a bit of a project.