Area-average (box) downscale: each output pixel is the exact coverage-weighted mean of the
source pixels under it. Done on linear premultiplied values, which is what makes it correct
(averaging sRGB darkens, averaging straight colour lets transparent pixels bleed in).
Area-average (box) downscale: each output pixel is the exact coverage-weighted mean of the source pixels under it. Done on linear premultiplied values, which is what makes it correct (averaging sRGB darkens, averaging straight colour lets transparent pixels bleed in).