https://mcmizzle.com/blog/ Engineering notes from building McMizzle's apps — tvOS, watchOS, HealthKit, BLE, and the parts the documentation leaves out. en-us https://mcmizzle.com/blog/watertight-mesh-wrong-shape/ https://mcmizzle.com/blog/watertight-mesh-wrong-shape/ Tue, 01 Sep 2026 12:00:00 +0000 A plate printed with 4 mm tongues of material reaching into openings that should have had a 1.4 mm border, and every printability check was green. Offsetting a polygon by moving its vertices spikes at sharp corners and folds through itself at tight curves — and an even-odd fill closes a folded ring as happily as a good one, so the mesh comes out watertight, island-free and slicing clean. https://mcmizzle.com/blog/videotoolbox-early-keyframes-hls-segments/ https://mcmizzle.com/blog/videotoolbox-early-keyframes-hls-segments/ Tue, 25 Aug 2026 12:00:00 +0000 One segment a minute came out at double length on a real camera, and never once on synthetic test video. The max keyframe interval is a ceiling, not a schedule — encoders spend keyframes early on scene changes — and it counts the timestamps you supply rather than wall clock. Half of that is documented, on a page about a different property. https://mcmizzle.com/blog/tvos-top-shelf-stale-cache/ https://mcmizzle.com/blog/tvos-top-shelf-stale-cache/ Mon, 03 Aug 2026 12:00:00 +0000 The tile drew a placeholder for hours after the code was correct again. The Home screen caches the rendered tile, dedupes incoming content against it, and that cache survives uninstalling the app — only a reboot cleared it. Plus what actually works for getting logs out of a tvOS extension, and what an extension can and can't do with an App Group. https://mcmizzle.com/blog/healthkit-widget-shows-zero/ https://mcmizzle.com/blog/healthkit-widget-shows-zero/ Mon, 27 Jul 2026 12:00:00 +0000 The widget was wrong every morning and right the moment I opened the app — but its timestamp was fresh, so it wasn't stale, it was freshly wrong. HealthKit's store is encrypted while the phone is locked, and a query that fails for that reason is indistinguishable from a day with no data unless you read the error.