| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #pragma once |
| |
| // skcms.h contains the entire public API for skcms. |
| |
| #include <stdbool.h> |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| // A row-major 3x3 matrix (ie vals[row][col]) |
| typedef struct { |
| float vals[3][3]; |
| } skcms_Matrix3x3; |
| |
| // A row-major 3x4 matrix (ie vals[row][col]) |
| typedef struct { |
| float vals[3][4]; |
| } skcms_Matrix3x4; |
| |
| // A transfer function mapping encoded values to linear values, |
| // represented by this 7-parameter piecewise function: |
| // |
| // linear = sign(encoded) * (c*|encoded| + f) , 0 <= |encoded| < d |
| // = sign(encoded) * ((a*|encoded| + b)^g + e), d <= |encoded| |
| // |
| // (A simple gamma transfer function sets g to gamma and a to 1.) |
| typedef struct { |
| float g, a,b,c,d,e,f; |
| } skcms_TransferFunction; |
| |
| // Unified representation of 'curv' or 'para' tag data, or a 1D table from 'mft1' or 'mft2' |
| typedef struct { |
| union { |
| struct { |
| uint32_t alias_of_table_entries; |
| skcms_TransferFunction parametric; |
| }; |
| struct { |
| uint32_t table_entries; |
| const uint8_t* table_8; |
| const uint8_t* table_16; |
| }; |
| }; |
| } skcms_Curve; |
| |
| typedef struct { |
| // Optional: N 1D curves, followed by an N-dimensional CLUT. |
| // If input_channels == 0, these curves and CLUT are skipped, |
| // Otherwise, input_channels must be in [1, 4]. |
| uint32_t input_channels; |
| skcms_Curve input_curves[4]; |
| uint8_t grid_points[4]; |
| const uint8_t* grid_8; |
| const uint8_t* grid_16; |
| |
| // Optional: 3 1D curves, followed by a color matrix. |
| // If matrix_channels == 0, these curves and matrix are skipped, |
| // Otherwise, matrix_channels must be 3. |
| uint32_t matrix_channels; |
| skcms_Curve matrix_curves[3]; |
| skcms_Matrix3x4 matrix; |
| |
| // Required: 3 1D curves. Always present, and output_channels must be 3. |
| uint32_t output_channels; |
| skcms_Curve output_curves[3]; |
| } skcms_A2B; |
| |
| typedef struct { |
| const uint8_t* buffer; |
| |
| uint32_t size; |
| uint32_t data_color_space; |
| uint32_t pcs; |
| uint32_t tag_count; |
| |
| // skcms_Parse() will set commonly-used fields for you when possible: |
| |
| // If we can parse red, green and blue transfer curves from the profile, |
| // trc will be set to those three curves, and has_trc will be true. |
| bool has_trc; |
| skcms_Curve trc[3]; |
| |
| // If this profile's gamut can be represented by a 3x3 transform to XYZD50, |
| // skcms_Parse() sets toXYZD50 to that transform and has_toXYZD50 to true. |
| bool has_toXYZD50; |
| skcms_Matrix3x3 toXYZD50; |
| |
| // If the profile has a valid A2B0 tag, skcms_Parse() sets A2B to that data, |
| // and has_A2B to true. |
| bool has_A2B; |
| skcms_A2B A2B; |
| } skcms_ICCProfile; |
| |
| // Parse an ICC profile and return true if possible, otherwise return false. |
| // The buffer is not copied, it must remain valid as long as the skcms_ICCProfile |
| // will be used. |
| bool skcms_Parse(const void*, size_t, skcms_ICCProfile*); |
| |
| bool skcms_ApproximateCurve(const skcms_Curve* curve, skcms_TransferFunction* approx, |
| float* max_error); |
| |
| // A specialized approximation for transfer functions with gamma between 1 and 3. |
| // f(x) = Ax^3 + Bx^2 + (1-A-B)x |
| typedef struct { |
| float A,B; |
| } skcms_TF13; |
| |
| bool skcms_ApproximateCurve13(const skcms_Curve* curve, skcms_TF13* approx, float* max_error); |
| |
| typedef struct { |
| uint32_t signature; |
| uint32_t type; |
| uint32_t size; |
| const uint8_t* buf; |
| } skcms_ICCTag; |
| |
| void skcms_GetTagByIndex (const skcms_ICCProfile*, uint32_t idx, skcms_ICCTag*); |
| bool skcms_GetTagBySignature(const skcms_ICCProfile*, uint32_t sig, skcms_ICCTag*); |
| |
| typedef enum { |
| skcms_PixelFormat_RGB_565, |
| skcms_PixelFormat_BGR_565, |
| |
| skcms_PixelFormat_RGB_888, |
| skcms_PixelFormat_BGR_888, |
| skcms_PixelFormat_RGBA_8888, |
| skcms_PixelFormat_BGRA_8888, |
| |
| skcms_PixelFormat_RGBA_1010102, |
| skcms_PixelFormat_BGRA_1010102, |
| |
| skcms_PixelFormat_RGB_161616, // Big-endian. Pointers must be 16-bit aligned. |
| skcms_PixelFormat_BGR_161616, |
| skcms_PixelFormat_RGBA_16161616, |
| skcms_PixelFormat_BGRA_16161616, |
| |
| skcms_PixelFormat_RGB_hhh, // 1-5-10 half-precision float. |
| skcms_PixelFormat_BGR_hhh, // Pointers must be 16-bit aligned. |
| skcms_PixelFormat_RGBA_hhhh, |
| skcms_PixelFormat_BGRA_hhhh, |
| |
| skcms_PixelFormat_RGB_fff, // 1-8-23 single-precision float (the normal kind). |
| skcms_PixelFormat_BGR_fff, // Pointers must be 32-bit aligned. |
| skcms_PixelFormat_RGBA_ffff, |
| skcms_PixelFormat_BGRA_ffff, |
| } skcms_PixelFormat; |
| |
| // We always store any alpha channel linearly. In the chart below, tf-1() is the inverse |
| // transfer function for the given color profile (applying the transfer function linearizes). |
| |
| // We treat opaque as a strong requirement, not just a performance hint: we will ignore |
| // any source alpha and treat it as 1.0, and will make sure that any destination alpha |
| // channel is filled with the equivalent of 1.0. |
| |
| // When premultiplying and/or using a non-linear transfer function, it's important |
| // that we know the order the operations are applied. If you're used to working |
| // with non-color-managed drawing systems, PremulAsEncoded is probably the "premul" |
| // you're looking for; if you want linear blending, PremulLinear is the choice for you. |
| |
| typedef enum { |
| skcms_AlphaFormat_Opaque, // alpha is always opaque |
| // tf-1(r), tf-1(g), tf-1(b), 1.0 |
| skcms_AlphaFormat_Unpremul, // alpha and color are unassociated |
| // tf-1(r), tf-1(g), tf-1(b), a |
| skcms_AlphaFormat_PremulAsEncoded, // premultiplied while encoded |
| // tf-1(r)*a, tf-1(g)*a, tf-1(b)*a, a |
| skcms_AlphaFormat_PremulLinear, // premultiplied while linear |
| // tf-1(r*a), tf-1(g*a), tf-1(b*a), a |
| } skcms_AlphaFormat; |
| |
| // Convert npixels pixels from src format and color profile to dst format and color profile |
| // and return true, otherwise return false. It is safe to alias dst == src if dstFmt == srcFmt. |
| bool skcms_Transform(const void* src, |
| skcms_PixelFormat srcFmt, |
| skcms_AlphaFormat srcAlpha, |
| const skcms_ICCProfile* srcProfile, |
| void* dst, |
| skcms_PixelFormat dstFmt, |
| skcms_AlphaFormat dstAlpha, |
| const skcms_ICCProfile* dstProfile, |
| size_t npixels); |
| |
| #ifdef __cplusplus |
| } |
| #endif |