Hey! I'm Sergey and I'm building a macOS screen recorder that enhances recordings by smoothing cursor movement and generating zoom animations based on clicks.
Why I built this
Most screen recordings feel static and hard to follow, especially in tutorials and product demos. I wanted recordings look more polished and cinematic like a professional ad
From Chrome Extension to macOS App
I started building this product about 2 years ago as a Chrome extension. After releasing it, I realized I would never reach the level of quality and performance I wanted with a browser-based tool, so at the beginning of 2025 I decided to pivot to a native macOS app.
I spent around 3 months rewriting the entire codebase for Electron. I'm still using Next.js under the hood because the original Chrome extension was built with it, but I plan to switch to Vite in the future since it's lighter and I don't need backend functionality in a desktop app.
The Challenge of Cursor Tracking
Overall, I've spent roughly 2 years building the product. The most interesting part has been tracking cursor movements during recording and transforming that data into smooth cursor motion and click-driven zoom effects.
I use Swift scripts for low-level cursor tracking and then run a post-processing pipeline that handles resampling to timeline FPS, outlier-jump clamping, stillness detection with snap-to-median behavior, cursor-type flicker smoothing, and coordinate normalization for area versus full-screen recordings. Clicks are converted into timed zoom segments with easing curves. This makes playback feel intentional rather than jumpy.
Why I Switched from Remotion to PixiJS
For video preview and export, I use PixiJS. Before that, I was using Remotion, which provided most of the functionality I needed, but rendering was slower because it relied on a Chromium + FFmpeg pipeline. Since PixiJS uses WebGL, 4K video rendering is significantly faster.
The migration took about 3 weeks. In the end, rendering speed improved by roughly 3–4× on the same hardware and projects. It was one of the more challenging rewrites, but I was relieved when everything finally came together.
High-level pipeline
Recording → Swift cursor capture → Post-processing → Zoom segment generation → WebGL rendering (PixiJS) → Export
Lessons learned
The hardest part wasn't rendering or recording—it was handling edge cases in cursor tracking. Small inconsistencies (jitter, missed frames, OS-level cursor changes) completely break the illusion of smooth motion.
Building with AI
I probably wouldn't have been able to build this product without AI assistants. Before this project, I had never built an Electron app, and many aspects of desktop development were completely new to me.
The first users uncovered plenty of bugs, platform-specific issues, and edge cases that I didn't even know existed. A large part of the last year has been spent tracking down those problems, improving reliability, and polishing the overall experience.
Stack
- Electron
- Next.js (migration planned to Vite)
- Swift (cursor tracking, screen and camera recording)
- PixiJS (rendering + export)
The product is called Screen Charm: https://screencharm.com
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