Crate pdfboss_icc 

Cleanroom ICC profile parser and colour transform (ICC.1:2010, v2 and v4 profiles) for pdfboss.

parse reads a profile’s header, tag table, and default device-to-PCS transform: matrix/TRC and grayTRC models (Annex F), or an A2B0 lookup transform (lut8Type, lut16Type, lutAToBType). Profile::transform then maps device components to non-linear sRGB in 0..=1: PCS values are chromatically adapted from the D50 PCS illuminant to D65 with the linear Bradford matrix (Annex E) and converted through the IEC 61966-2-1 primary matrix and transfer. Everything is combined at parse time; a transform call is curve lookups, one 3x3 multiply, and the sRGB encode, with no allocation.

A 3-channel matrix/TRC profile whose composed transform is the identity within SRGB_TOLERANCE at the probe points reports DeviceSpace::Rgb from Profile::device_equivalent (a gray profile analogously reports DeviceSpace::Gray), so callers can keep painting in device space. Only the profile’s default transform is used; rendering intents are not switched.

Structs

Profile

A parsed profile: its device channel count and compiled transform.

Enums

DeviceSpace

The device space a profile’s transform is indistinguishable from.

IccError

Why a profile would not parse.

Constants

D50

The nCIEXYZ values of the PCS illuminant (D50), ICC.1:2010 clause 7.2.16.

SRGB_TOLERANCE

Per-channel tolerance for the composed-identity probe behind Profile::device_equivalent: about 2,5 steps of 8-bit output. A pure gamma-2,2 curve misses the sRGB transfer by ~0,03 at 1/16 input, so it honestly fails.

Functions

lab_to_xyz

CIE Lab* to XYZ relative to white, per the CIE definition used by ISO 32000-1 clause 8.6.5.4: the inverse transfer g(t) = t^3 above 6/29 continues linearly with slope 108/841 below it.

mat_apply

Applies a 3x3 matrix to a column vector.

mat_mul

Row-major 3x3 matrix product.

parse

Parses an ICC profile and compiles its default device-to-sRGB transform.

srgb_encode

The IEC 61966-2-1 sRGB opto-electronic transfer: linear 0..=1 in, non-linear 0..=1 out. Out-of-range and non-finite inputs clamp.

xyz_to_linear_srgb

Matrix taking XYZ relative to white to linear sRGB: Bradford adaptation to D65 followed by the sRGB primary matrix.

Type Aliases

Mat3

A row-major 3x3 matrix.