7f87812c30
This patch improves the image resampling (scaling) code in CBGFX to use the Lanczos algorithm that is widely considered the "best" resampling algorithm (e.g. also the first choice in Python's PIL library). It is of course much more elaborate and therefore slower than bilinear resampling, but a lot of the difference can be made up with optimizations, and the resulting code was found to still produce acceptable speeds for existing Chrome OS UI use cases (on an Arm Cortex-A55 device, time to scale an image to 1101x593 went from ~88ms to ~275ms, a little over 3x slowdown). Nevertheless, if this should be too slow for anyone there's also an option to tune it down a little, but still much better than bilinear (same operation was ~170ms with this). Example images (scaled up by a factor of 7): Old (bilinear): https://i.imgur.com/ytr2n4Z.png New (Lanczos a=3): https://i.imgur.com/f0vKluM.png Signed-off-by: Julius Werner <jwerner@chromium.org> Change-Id: Idde6f61865bfac2801ee4fff40ac64e4ebddff1a Reviewed-on: https://review.coreboot.org/c/coreboot/+/42792 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Yu-Ping Wu <yupingso@google.com> Reviewed-by: Hung-Te Lin <hungte@chromium.org> |
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| coreinfo | ||
| external | ||
| libpayload | ||
| linuxcheck | ||
| nvramcui | ||
| Kconfig | ||
| Makefile.inc | ||
