Plotterfun
A collection of algorithms for turning images into vector art.
Try it out here: https://mitxela.com/plotterfun/
The aim is to make it simple to develop new algorithms. Each algorithm is a separate .js file and is loaded as a webworker. Some of the algorithms are my versions of other vector art programs.
Squiggle
Based on SquiggleCam / SquiggleDraw. The left/right, spiral and PolygonSpiral versions apply the same squiggling to different paths.
SippleGen
Iterative weighted voronoi stippling, with 2-opt travelling-salesman route optimization. I love StippleGen but it runs very slowly, and because it's single threaded the interface freezes while it's running. In porting it to javascript, I significantly rewrote parts of it in order to get it to run much faster.
Makes use of rhill's voronoi library and StackBlur, both included in minimized form in the 'external' directory.
Linedraw
Port of linedraw.py by LingDong-
Other algorithms
The rest are things I came up with on my own. Delaunay is very similar to StippleGen, but after the weighted voronoi iteration the Delaunay Triangulation is plotted. There are a few variations on squiggles (sawtooth, springs) and other algorithms not based on anything in particular. Try them out, it should be fairly clear what each control does.
Usage
When you load a picture, you can drag the preview image around and zoom with the scroll wheel.
The size is limited to 800px when you first load the image, but you're welcome to make it as big as you like. This is mostly because some algorithms have hard-coded defaults (like blur radius or border size) which work best with images of about 800px wide. However, if you're trying to produce a Stipple or Delaunay image with a huge number of stipples, the integration will not work very well if the polygons are too small, so making the image bigger can improve the results.
Each slider has a text box next to it, where you can type in an arbitrary number. Absurd numbers may crash the algorithm, but in the worst case scenario refreshing the page will fix everything. You're welcome to attempt a million stipples if it takes your fancy.
Plotting
When you're happy with the vector image, download the SVG and open it in Inkscape. Resize it (change units to mm or inches) then head to Extensions > Export > Plot.
Developing new algorithms
Each algorithm is in its own .js file. The helpers.js file can be imported to simplify things. The algo first sends a message describing the controls it needs, which usually starts with defaultControls (brightness/contrast/inverted etc). In addition to sliders, checkboxes and combo boxes are possible.
The worker is then sent a message with configuration (describing the state of the controls) and the imagedata. If using the default controls, pixelProcessor from helpers.js will return a function that lets you get the darkness of a pixel after the brightness/contrast has been applied.
Each time a control is changed, the algorithm is killed and restarted. If the algorithm is complex, you can post messages to the main thread with status information. To send vector data, use postCircles or postLines to send paths, or lists of paths.
For complex algorithms, specifying noRestart: true on a control will stop it from killing and restarting the worker. However, since workers won't receive another message until they've finished working, you will need to periodically stop and check for messages to make use of this. The approach I took in stipple.js was to wrap chunks of work in setTimeout() calls and make the main rendering an async function that can await them. You might describe this as a method-of-least-ugliness.
I strongly recommend reading the code for the existing algorithms, I've tried to make things as clear as possible.
About webworkers
For "security" reasons, browsers refuse to run webworkers from files loaded straight from your disk. As a hacky fallback, plotterfun will detect this happening and append the script to the document, so that simple algorithms can still be developed this way. Complex algorithms will either freeze the interface while they run, or if they're asynchronous, risk running repeatedly since they cannot be killed properly.
It's much better to host the files locally for development, using either node's http-server or python -m http.server. Be aware that browsers aggressively cache webworkers, it's essential to have the developer tools open and "Disable Cache" ticked, or you will not have any fun.