I have made a large fraction of the existing alfaerie SVGs, (Greg did the others), but I never tried to do it in an automated way. I use Inkscape on Linux, import the GIF image into it (e.g. by 'open with'), magnify it to the desired nominal size of the SVGs (2048 x 2048?), and then trace out all outlines by placing points on those from Bezier curves. You don't need many points; for a circle a hexagon would do. (But of course there is a special function for drawing circles.) After the curve is a closed loop, I select it with the 'edit points' tool. With that I grab all the sides of the polygon that should not be straight lines, to bend those. This makes tow 'handles' appear at the ends of the side, the direction of which I adjust to the tangent of the curve in the GIF, while their length is adjusted to give a smooth curve. Then I adjust the width, color, fill color and corner rounding therough the menu that appears clicking on the lower left of the bottom tools bar. (I often start with red instead of black, to see whether I cover the outlines of the GIF well.) Finally I remove the GIF, and save the lot (after grouping everything with the menu).
This is not difficult, but it is tedious for complex images. This is why I haven't done it for every GIF that exists. That it exists doesn't necessarily mean it is useful. So I convert the remaining images only 'on demand', when I am equiping articles on variants that the AI of the Interactive Diagram can handle with such Diagrams, and the original diagram in that article used an image that doesn't exist as SVG yet.
I have made a large fraction of the existing alfaerie SVGs, (Greg did the others), but I never tried to do it in an automated way. I use Inkscape on Linux, import the GIF image into it (e.g. by 'open with'), magnify it to the desired nominal size of the SVGs (2048 x 2048?), and then trace out all outlines by placing points on those from Bezier curves. You don't need many points; for a circle a hexagon would do. (But of course there is a special function for drawing circles.) After the curve is a closed loop, I select it with the 'edit points' tool. With that I grab all the sides of the polygon that should not be straight lines, to bend those. This makes tow 'handles' appear at the ends of the side, the direction of which I adjust to the tangent of the curve in the GIF, while their length is adjusted to give a smooth curve. Then I adjust the width, color, fill color and corner rounding therough the menu that appears clicking on the lower left of the bottom tools bar. (I often start with red instead of black, to see whether I cover the outlines of the GIF well.) Finally I remove the GIF, and save the lot (after grouping everything with the menu).
This is not difficult, but it is tedious for complex images. This is why I haven't done it for every GIF that exists. That it exists doesn't necessarily mean it is useful. So I convert the remaining images only 'on demand', when I am equiping articles on variants that the AI of the Interactive Diagram can handle with such Diagrams, and the original diagram in that article used an image that doesn't exist as SVG yet.