Canvas Pixel Transformation: Beauty comes slowly
summary
A Mapbox canvas is read with Mapbox webgl readPixels and converted into a 2D ImageData array, a flood‑fill area detector paints road‑delimited mosaics, and the prototype runs in a React + TypeScript app. Pixel loop costs dominate: a fullHD frame (~5 million pixels) takes up to 5 seconds (uploader estimated >2s earlier). Moving the flood fill into web workers with worker‑loader prevents UI jank and aborts stale jobs, but overall rendering remains slow and needs a WebGL or WASM reimplementation.
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chapters (10)
- 0:00Canvas pixel manipulation
- 2:40React canvas demo setup
- 4:50Painting rectangle and pixels
- 10:08Canvas size vs Mapbox
- 13:06Copying Mapbox pixels
- 16:42Area detection algorithm
- 23:16UI blocking with workers
- 28:46Integrating web workers
- 32:19Worker performance
- 33:29Conclusion
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