Module soft_light 

Photoshop-style soft light blend, over 2-D (H, W) and 3-D (H, W, C) arrays.

Matches blend.py’s soft_light() exactly (verified in tests/test_blend.py’s Rust-parity tests, when the extension is built). Per element, with base a and blend b:

b <= 0.5:  2ab + a²(1 - 2b)
b >  0.5:  2a(1 - b) + sqrt(clamp(a, 0, 1)) · (2b - 1)

and the result is clamped to [0, 1].

Which function to call

Call soft_light_core (2-D) or soft_light_rgb_core (3-D). They pick the serial or parallel path using PARALLEL_THRESHOLD.

The *_serial/*_parallel variants are public only so benches/blend_bench.rs can time both paths at every array size to tune that threshold. Benches are separate crates and can only call pub items.

Functions

soft_light_core

Soft light blend of two 2-D arrays. The entry point for 2-D inputs.

soft_light_parallel

Soft light blend of two 2-D arrays, parallelised with rayon.

soft_light_rgb_core

Soft light blend of two 3-D (H, W, C) arrays, e.g. RGB or RGBA imagery, in a single pass. The entry point for multi-channel inputs.

soft_light_rgb_parallel

Soft light blend of two 3-D arrays, parallelised with rayon.

soft_light_rgb_serial

Soft light blend of two 3-D arrays, single-threaded.

soft_light_serial

Soft light blend of two 2-D arrays, single-threaded.