martin brookandGitHub 1df543d48d perf: Eliminate per-pixel overheads in image rendering (#1293) ...

## Summary

Replace per-pixel getRenderMode() + rotateCoordinates() + bounds checks
with a DirectPixelWriter struct that pre-computes orientation and render
mode state once per row. Use bitwise ops instead of division/modulo for
cache pixel packing. Skip PNG cache allocation when buffer exceeds 48KB
(framebuffer size) since PNG decode is fast enough that caching provides
minimal benefit, and the large buffer competes with the 44KB PNG decoder
for heap.

## Additional Context
Measured improvements on ESP32-C3 @ 160MHz:
- JPEG decode: 5-7% faster (1:1 scale)
- PNG decode: 15-20% faster (1:1 scale)
- Cache renders: 3-6% faster across both formats
- Eliminates "Failed to allocate cache buffer" errors for large PNGs

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### AI Usage

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2026-03-30 11:03:49 -05:00

..

Epub

perf: Eliminate per-pixel overheads in image rendering (#1293)

2026-03-30 11:03:49 -05:00

Epub.cpp

perf: Avoid creating strings for file extension checks (#1303)

2026-03-05 10:12:22 -06:00

Epub.h

feat: slim footnotes support (#1031)

2026-02-26 08:47:34 -06:00