Hi, I actually did an experimental implementation of SLUG a long time ago when Eric Lengyel released his first paper on it. It is very elegant and performed well. But due to the patent restrictions, we could never go forward with it unfortunately. If the public domain release had come earlier, my guess is that we would have gone with SLUG instead of the algorithm we picked for the curve renderer, which is an older approach and has an expensive preparation phase.
This is still an option, though. We might be able to just replace the current implementation and get both better and faster rendering for shapes (and large text) without any changes to API. Since most text will still go through the SDF path, I think the primary value will be for general shapes rendering, scalable SVG icons etc. But it is definitely something I want to look into in the near future. We would also need to verify that the patent disclaimer they filed is sufficient for our use of course. The patent still exists, just with a disclaimer, as far as I understand, so it would mean in practice that all Qt applications will ship with patented code. Hopefully it is ok, but I prefer someone with more expertise than me to make the call on that. 🙂 -- Eskil Abrahamsen Blomfeldt Principal Manager, Graphics Engines The Qt Company Sandakerveien 116 0484 Oslo, Norway [email protected] http://qt.io Confidential ________________________________ From: Development <[email protected]> on behalf of Fatih Uzunoğlu <[email protected]> Sent: Saturday, October 3, 2026 2:19 PM To: [email protected] <[email protected]> Subject: [Development] Any plans of supporting Slug text rendering? Hello, The Slug algorithm [1] offers a novel approach for rendering text, and some see it as being better in all aspects (for modern computers) than using SDFs with texture atlas (at least Qt Quick uses this by default). There is the new curve renderer in Qt Quick since Qt 6.6 (https://www.qt.io/blog/smooth-vector-graphics-in-qt-quick), but as per my understanding it works fundamentally different and can be very heavy for simple text rendering, it seems most relevant for complex shape rendering (at least for the Latin alphabet, glyphs are very simple). The algorithm was patented up until very recently, but it is no longer the case as per the author, so I think it should be safe for Qt to incorporate the algorithm. It also seems to be (similar to SDF) very trivial to implement, so it would not take much effort from Qt's side to support it. Going this way would also make multi-channel SDF redundant, if there were such plans of using MSDF for rendering text, I think with the Slug algorithm it could be abandoned. Some interesting discussion can be found here: https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fnews.ycombinator.com%2Fitem%3Fid%3D49908962&data=05%7C02%7C%7C2fe3288143164b98328108df2148d67b%7C20d0b167794d448a9d01aaeccc1124ac%7C0%7C0%7C639266269309469229%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=6GnQ0OSTVjw6DK%2FHiErlO8YPKhutMEGQRLCPgsL%2BIKI%3D&reserved=0<https://news.ycombinator.com/item?id=49908962>. [1] https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsluglibrary.com%2F&data=05%7C02%7C%7C2fe3288143164b98328108df2148d67b%7C20d0b167794d448a9d01aaeccc1124ac%7C0%7C0%7C639266269309485033%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C60000%7C%7C%7C&sdata=V4Y31Xa3zDvd%2FwqT3o3o2cYMvkdaKyUpHKnfqPi2WbE%3D&reserved=0<https://sluglibrary.com/> Best Regards, Fatih Uzunoğlu -- Development mailing list [email protected] https://lists.qt-project.org/listinfo/development
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