Roll skia/third_party/skcms 3f444c5..3e527c6 (1 commits)

https://skia.googlesource.com/skcms.git/+log/3f444c5..3e527c6

2018-05-17 brianosman@google.com Added skcms_AreApproximateInverses(Curve, TransferFunction)


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CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
TBR=herb@google.com

Change-Id: Ia10c2fe8dc17972b8e5570819ff6ac197f4d77f8
Reviewed-on: https://skia-review.googlesource.com/128984
Commit-Queue: skcms-skia-autoroll <skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Reviewed-by: skcms-skia-autoroll <skcms-skia-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>

1 files changed, 16 insertions, 6 deletions

diff --git a/third_party/skcms/skcms.h b/third_party/skcms/skcms.h
index ece944c56b..97728c4c8f 100644
--- a/third_party/skcms/skcms.h
+++ b/third_party/skcms/skcms.h
@@ -56,12 +56,6 @@ typedef union skcms_Curve {
     };
 } skcms_Curve;
 
-// Practical equality test for two skcms_Curves.
-// The implementation is subject to change, but it will always try to answer
-// "can I substitute A for B?" and "can I skip transforming from A to B?".
-SKCMS_API bool skcms_ApproximatelyEqualCurves(const skcms_Curve* A,
-                                              const skcms_Curve* B);
-
 typedef struct skcms_A2B {
     // Optional: N 1D curves, followed by an N-dimensional CLUT.
     // If input_channels == 0, these curves and CLUT are skipped,
@@ -115,12 +109,28 @@ SKCMS_API const skcms_ICCProfile* skcms_sRGB_profile(void);
 // Ditto for XYZD50, the most common profile connection space.
 SKCMS_API const skcms_ICCProfile* skcms_XYZD50_profile(void);
 
+SKCMS_API const skcms_TransferFunction* skcms_sRGB_TransferFunction(void);
+SKCMS_API const skcms_TransferFunction* skcms_sRGB_Inverse_TransferFunction(void);
+SKCMS_API const skcms_TransferFunction* skcms_Identity_TransferFunction(void);
+
 // Practical equality test for two skcms_ICCProfiles.
 // The implementation is subject to change, but it will always try to answer
 // "can I substitute A for B?" and "can I skip transforming from A to B?".
 SKCMS_API bool skcms_ApproximatelyEqualProfiles(const skcms_ICCProfile* A,
                                                 const skcms_ICCProfile* B);
 
+// Practical test that answers: Is curve roughly the inverse of inv_tf? Typically used by passing
+// the inverse of a known parametric transfer function (like sRGB), to determine if a particular
+// curve is very close to sRGB.
+SKCMS_API bool skcms_AreApproximateInverses(const skcms_Curve* curve,
+                                            const skcms_TransferFunction* inv_tf);
+
+// Similar to above, answering the question for all three TRC curves of the given profile. Again,
+// passing skcms_sRGB_InverseTransferFunction as inv_tf will answer the question:
+// "Does this profile have a transfer function that is very close to sRGB?"
+SKCMS_API bool skcms_TRCs_AreApproximateInverse(const skcms_ICCProfile* profile,
+                                                const skcms_TransferFunction* inv_tf);
+
 // 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.