diff options
Diffstat (limited to 'third_party/skcms/src/ICCProfile.c')
| -rw-r--r-- | third_party/skcms/src/ICCProfile.c | 46 |
1 files changed, 41 insertions, 5 deletions
diff --git a/third_party/skcms/src/ICCProfile.c b/third_party/skcms/src/ICCProfile.c index 9c504cd3ce..a21abd0041 100644 --- a/third_party/skcms/src/ICCProfile.c +++ b/third_party/skcms/src/ICCProfile.c @@ -226,7 +226,7 @@ static bool read_curve_curv(const uint8_t* buf, uint32_t size, curve->parametric.e = 0.0f; curve->parametric.f = 0.0f; if (value_count == 0) { - // Empty tables are a shorthand for linear + // Empty tables are a shorthand for an identity curve curve->parametric.g = 1.0f; } else { // Single entry tables are a shorthand for simple gamma @@ -581,15 +581,51 @@ static bool read_tag_mab(const skcms_ICCTag* tag, skcms_A2B* a2b, bool pcs_is_xy } static bool read_a2b(const skcms_ICCTag* tag, skcms_A2B* a2b, bool pcs_is_xyz) { + bool ok = false; if (tag->type == make_signature('m', 'f', 't', '1')) { - return read_tag_mft1(tag, a2b); + ok = read_tag_mft1(tag, a2b); } else if (tag->type == make_signature('m', 'f', 't', '2')) { - return read_tag_mft2(tag, a2b); + ok = read_tag_mft2(tag, a2b); } else if (tag->type == make_signature('m', 'A', 'B', ' ')) { - return read_tag_mab(tag, a2b, pcs_is_xyz); + ok = read_tag_mab(tag, a2b, pcs_is_xyz); + } + if (!ok) { + return false; } - return false; + // Detect and canonicalize identity tables. + skcms_Curve* curves[] = { + a2b->input_channels > 0 ? a2b->input_curves + 0 : NULL, + a2b->input_channels > 1 ? a2b->input_curves + 1 : NULL, + a2b->input_channels > 2 ? a2b->input_curves + 2 : NULL, + a2b->input_channels > 3 ? a2b->input_curves + 3 : NULL, + a2b->matrix_channels > 0 ? a2b->matrix_curves + 0 : NULL, + a2b->matrix_channels > 1 ? a2b->matrix_curves + 1 : NULL, + a2b->matrix_channels > 2 ? a2b->matrix_curves + 2 : NULL, + a2b->output_channels > 0 ? a2b->output_curves + 0 : NULL, + a2b->output_channels > 1 ? a2b->output_curves + 1 : NULL, + a2b->output_channels > 2 ? a2b->output_curves + 2 : NULL, + }; + + for (int i = 0; i < ARRAY_COUNT(curves); i++) { + skcms_Curve* curve = curves[i]; + + if (curve && curve->table_entries && curve->table_entries <= (uint32_t)INT_MAX) { + int N = (int)curve->table_entries; + + skcms_TransferFunction tf; + if (N == skcms_fit_linear(curve, N, 1.0f/(2*N), &tf) + && tf.c == 1.0f + && tf.f == 0.0f) { + curve->table_entries = 0; + curve->table_8 = NULL; + curve->table_16 = NULL; + curve->parametric = (skcms_TransferFunction){1,1,0,0,0,0,0}; + } + } + } + + return true; } void skcms_GetTagByIndex(const skcms_ICCProfile* profile, uint32_t idx, skcms_ICCTag* tag) { |