diff options
| -rw-r--r-- | third_party/skcms/skcms.h | 5 | ||||
| -rw-r--r-- | third_party/skcms/src/Transform.c | 97 |
2 files changed, 76 insertions, 26 deletions
diff --git a/third_party/skcms/skcms.h b/third_party/skcms/skcms.h index 39e3cbcdb7..08779a40e6 100644 --- a/third_party/skcms/skcms.h +++ b/third_party/skcms/skcms.h @@ -202,6 +202,11 @@ bool skcms_Transform(const void* src, const skcms_ICCProfile* dstProfile, size_t npixels); +// If profile cannot be used as a destination profile in skcms_Transform(), +// rewrite it with approximations where reasonable or by pulling from fallback +// (e.g. skcms_sRGB_profile) where not. +void skcms_EnsureUsableAsDestination(skcms_ICCProfile* profile, const skcms_ICCProfile* fallback); + #ifdef __cplusplus } #endif diff --git a/third_party/skcms/src/Transform.c b/third_party/skcms/src/Transform.c index b6b3e8e320..204bb9f1b7 100644 --- a/third_party/skcms/src/Transform.c +++ b/third_party/skcms/src/Transform.c @@ -354,6 +354,24 @@ static skcms_Matrix3x3 concat_3x3(const skcms_Matrix3x3* A, const skcms_Matrix3x return m; } +static bool prep_for_destination(const skcms_ICCProfile* profile, + skcms_Matrix3x3* fromXYZD50, + skcms_TransferFunction* invR, + skcms_TransferFunction* invG, + skcms_TransferFunction* invB) { + // We only support destinations with parametric transfer functions + // and with gamuts that can be transformed from XYZD50. + return profile->has_trc + && profile->has_toXYZD50 + && profile->trc[0].table_entries == 0 + && profile->trc[1].table_entries == 0 + && profile->trc[2].table_entries == 0 + && skcms_TransferFunction_invert(&profile->trc[0].parametric, invR) + && skcms_TransferFunction_invert(&profile->trc[1].parametric, invG) + && skcms_TransferFunction_invert(&profile->trc[2].parametric, invB) + && skcms_Matrix3x3_invert(&profile->toXYZD50, fromXYZD50); +} + bool skcms_Transform(const void* src, skcms_PixelFormat srcFmt, skcms_AlphaFormat srcAlpha, @@ -427,6 +445,11 @@ bool skcms_Transform(const void* src, srcAlpha == skcms_AlphaFormat_PremulLinear || dstAlpha == skcms_AlphaFormat_PremulLinear) { + if (!prep_for_destination(dstProfile, + &from_xyz, &inv_dst_tf_r, &inv_dst_tf_b, &inv_dst_tf_g)) { + return false; + } + if (srcProfile->has_A2B) { if (srcProfile->A2B.input_channels) { for (int i = 0; i < (int)srcProfile->A2B.input_channels; i++) { @@ -497,11 +520,6 @@ bool skcms_Transform(const void* src, *ops++ = Op_unpremul; } - // We only support destination gamuts that can be transformed from XYZD50. - if (!dstProfile->has_toXYZD50) { - return false; - } - // A2B sources should already be in XYZD50 at this point. // Others still need to be transformed using their toXYZD50 matrix. // N.B. There are profiles that contain both A2B tags and toXYZD50 matrices. @@ -517,9 +535,6 @@ bool skcms_Transform(const void* src, // There's a chance the source and destination gamuts are identical, // in which case we can skip the gamut transform. if (0 != memcmp(&dstProfile->toXYZD50, to_xyz, sizeof(skcms_Matrix3x3))) { - if (!skcms_Matrix3x3_invert(&dstProfile->toXYZD50, &from_xyz)) { - return false; - } // Concat the entire gamut transform into from_xyz, // now slightly misnamed but it's a handy spot to stash the result. from_xyz = concat_3x3(&from_xyz, to_xyz); @@ -527,25 +542,14 @@ bool skcms_Transform(const void* src, *args++ = &from_xyz; } - // Encode back to dst RGB using its parametric transfer functions. - if (dstProfile->has_trc && - dstProfile->trc[0].table_entries == 0 && - dstProfile->trc[1].table_entries == 0 && - dstProfile->trc[2].table_entries == 0 && - skcms_TransferFunction_invert(&dstProfile->trc[0].parametric, &inv_dst_tf_r) && - skcms_TransferFunction_invert(&dstProfile->trc[1].parametric, &inv_dst_tf_g) && - skcms_TransferFunction_invert(&dstProfile->trc[2].parametric, &inv_dst_tf_b)) { - - if (dstAlpha == skcms_AlphaFormat_PremulLinear) { - *ops++ = Op_premul; - } - - if (!is_identity_tf(&inv_dst_tf_r)) { *ops++ = Op_tf_r; *args++ = &inv_dst_tf_r; } - if (!is_identity_tf(&inv_dst_tf_g)) { *ops++ = Op_tf_g; *args++ = &inv_dst_tf_g; } - if (!is_identity_tf(&inv_dst_tf_b)) { *ops++ = Op_tf_b; *args++ = &inv_dst_tf_b; } - } else { - return false; + if (dstAlpha == skcms_AlphaFormat_PremulLinear) { + *ops++ = Op_premul; } + + // Encode back to dst RGB using its parametric transfer functions. + if (!is_identity_tf(&inv_dst_tf_r)) { *ops++ = Op_tf_r; *args++ = &inv_dst_tf_r; } + if (!is_identity_tf(&inv_dst_tf_g)) { *ops++ = Op_tf_g; *args++ = &inv_dst_tf_g; } + if (!is_identity_tf(&inv_dst_tf_b)) { *ops++ = Op_tf_b; *args++ = &inv_dst_tf_b; } } if (dstAlpha == skcms_AlphaFormat_Opaque) { @@ -582,3 +586,44 @@ bool skcms_Transform(const void* src, run(program, arguments, src, dst, n, src_bpp,dst_bpp); return true; } + +static void assert_usable_as_destination(const skcms_ICCProfile* profile) { +#if defined(NDEBUG) + (void)profile; +#else + skcms_Matrix3x3 fromXYZD50; + skcms_TransferFunction invR, invG, invB; + assert(prep_for_destination(profile, &fromXYZD50, &invR, &invG, &invB)); +#endif +} + +void skcms_EnsureUsableAsDestination(skcms_ICCProfile* profile, const skcms_ICCProfile* fallback) { + assert_usable_as_destination(fallback); + skcms_ICCProfile ok = *fallback; + + skcms_Matrix3x3 fromXYZD50; + if (profile->has_toXYZD50 && skcms_Matrix3x3_invert(&profile->toXYZD50, &fromXYZD50)) { + ok.toXYZD50 = profile->toXYZD50; + } + + for (int i = 0; profile->has_trc && i < 3; i++) { + skcms_TransferFunction inv; + if (profile->trc[i].table_entries == 0 + && skcms_TransferFunction_invert(&profile->trc[i].parametric, &inv)) { + ok.trc[i] = profile->trc[i]; + continue; + } + + // Note there's a little gap here that we could fill by allowing fitting + // parametric curves to non-invertible parametric curves. + + float max_error; + if (skcms_ApproximateCurve(&profile->trc[i], &ok.trc[i].parametric, &max_error)) { + // Parametric curves from skcms_ApproximateCurve() are guaranteed to be invertible. + ok.trc[i].table_entries = 0; + } + } + + *profile = ok; + assert_usable_as_destination(profile); +} |