Show HN: I made a WebGL-based app that traces images using circles I was fascinated by this [0] and this video [1]. After many struggles, I finally built this app that traces images using circles similar to what these videos had shown. The most challenging part (to me) is to find a way to convert images to vector lines. I had tried Potrace, but its output is not suitable for my use case: too many small elements share the same border. Potrace's goal is to represent the original image faithfully using vector lines. But I want to trace the image edges. After searching and trying some Potrace alternatives in vain, I finally found my keyword. Surprisingly (to me), it lies at the end of the wiki page of the very topic [2]. Then I found a paper [3] that has nice pseudocode and a C implementation. I rewrote the pseudocode in Rust because I wanted to experiment with rustwasm. Honestly, I didn't care much about the math behind it. From then, I could continue to finish the app and show it to the world. This app is also my chance to learn about rustwasm and WebGL. FYI: this app is offline-only; your images never leave your browser [0] https://www.youtube.com/watch?v=r6sGWTCMz2k [1] https://www.youtube.com/watch?v=-qgreAUpPwM [2] https://ift.tt/Pro6wkp [3] https://ift.tt/qeYthsw https://ift.tt/ugedaB4 March 2, 2022 at 11:56PM
Show HN: StreetComplete, an OpenStreetMap Editor for Humans StreetComplete is an OpenStreetMap[0] editor directed at people who want to contribute and want to do this using their smartphone, without learning how to edit things[1]. It is available as an Android application. It is intended to be used as one walks, with quests appearing as markers on the map. Selecting a marker allows one to answer a simple question. The answer will be added to the OpenStreetMap database, with app handling selecting objects for editing, transforming answer into OSM tags and making edits. OpenStreetMap account is needed to apply edits, but it is possible to start without it, make some edits and login/register later. Note: I am not the main author, but I am one of the active contributors. Github page is at https://ift.tt/2g8lasH and https://ift.tt/3nR9PzS shows what was recently released. [0]OpenStreetMap is a Wikipedia of maps, available on the open licence. This dataset is already used for many interestin...
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