Module color 

RGB arithmetic with explicit rounding contracts.

Functions

lerp_rgb

Interpolate using signed division toward zero. Clamp the numerator to the original denominator before replacing a zero divisor with one. Therefore a zero denominator always returns a, matching the caller contract.

lerp_rgb_q8

Q8 interpolation with arithmetic shift (rounding negative deltas down). t is a fraction over 256; 255 deliberately does not quite reach b.

scale_rgb

Scale each channel by a signed ratio, truncating toward zero, then clamp. den must be nonzero, each channel product must fit i32, and a product of i32::MIN must not be divided by -1.