3 files changed, 76 insertions, 1 deletions
diff --git a/third_party/skcms/skcms.h b/third_party/skcms/skcms.h
index 2053fe6828..36ac4a0fbc 100644
--- a/third_party/skcms/skcms.h
+++ b/third_party/skcms/skcms.h
@@ -221,6 +221,17 @@ SKCMS_API void skcms_EnsureUsableAsDestination(skcms_ICCProfile* profile,
 SKCMS_API void skcms_EnsureUsableAsDestinationWithSingleCurve(skcms_ICCProfile* profile,
                                                               const skcms_ICCProfile* fallback);
 
+// If profile can be used as a destination in skcms_Transform, return true. Otherwise, attempt to
+// rewrite it with approximations where reasonable. If successful, return true. If no reasonable
+// approximation exists, leave the profile unchanged and return false.
+SKCMS_API bool skcms_MakeUsableAsDestination(skcms_ICCProfile* profile);
+
+// If profile can be used as a destination with a single parametric transfer function (ie for
+// rasterization), return true. Otherwise, attempt to rewrite it with approximations where
+// reasonable. If successful, return true. If not reasonable approximation exists, leave the
+// profile unchanged and return false.
+SKCMS_API bool skcms_MakeUsableAsDestinationWithSingleCurve(skcms_ICCProfile* profile);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/third_party/skcms/src/Transform.c b/third_party/skcms/src/Transform.c
index 7aaed63cf6..ae26e71804 100644
--- a/third_party/skcms/src/Transform.c
+++ b/third_party/skcms/src/Transform.c
@@ -697,3 +697,67 @@ void skcms_EnsureUsableAsDestinationWithSingleCurve(skcms_ICCProfile* profile,
     *profile = result;
     assert_usable_as_destination(profile);
 }
+
+bool skcms_MakeUsableAsDestination(skcms_ICCProfile* profile) {
+    skcms_Matrix3x3 fromXYZD50;
+    if (!profile->has_trc || !profile->has_toXYZD50
+        || !skcms_Matrix3x3_invert(&profile->toXYZD50, &fromXYZD50)) {
+        return false;
+    }
+
+    skcms_TransferFunction tf[3];
+    for (int i = 0; i < 3; i++) {
+        skcms_TransferFunction inv;
+        if (profile->trc[i].table_entries == 0
+            && skcms_TransferFunction_invert(&profile->trc[i].parametric, &inv)) {
+            tf[i] = profile->trc[i].parametric;
+            continue;
+        }
+
+        float max_error;
+        // Parametric curves from skcms_ApproximateCurve() are guaranteed to be invertible.
+        if (!skcms_ApproximateCurve(&profile->trc[i], &tf[i], &max_error)) {
+            return false;
+        }
+    }
+
+    for (int i = 0; i < 3; ++i) {
+        profile->trc[i].table_entries = 0;
+        profile->trc[i].parametric = tf[i];
+    }
+
+    assert_usable_as_destination(profile);
+    return true;
+}
+
+bool skcms_MakeUsableAsDestinationWithSingleCurve(skcms_ICCProfile* profile) {
+    // Operate on a copy of profile, so we can choose the best TF for the original curves
+    skcms_ICCProfile result = *profile;
+    if (!skcms_MakeUsableAsDestination(&result)) {
+        return false;
+    }
+
+    int best_tf = 0;
+    float min_max_error = INFINITY_;
+    for (int i = 0; i < 3; i++) {
+        skcms_TransferFunction inv;
+        skcms_TransferFunction_invert(&result.trc[i].parametric, &inv);
+
+        float err = 0;
+        for (int j = 0; j < 3; ++j) {
+            err = fmaxf_(err, max_roundtrip_error(&inv, &profile->trc[j]));
+        }
+        if (min_max_error > err) {
+            min_max_error = err;
+            best_tf = i;
+        }
+    }
+
+    for (int i = 0; i < 3; i++) {
+        result.trc[i].parametric = result.trc[best_tf].parametric;
+    }
+
+    *profile = result;
+    assert_usable_as_destination(profile);
+    return true;
+}
diff --git a/third_party/skcms/version.sha1 b/third_party/skcms/version.sha1
index 1284041000..d75996c241 100755
--- a/third_party/skcms/version.sha1
+++ b/third_party/skcms/version.sha1
@@ -1 +1 @@
-513d372c015ed44b5649308d45728708cdf956ee
-\ No newline at end of file
+baef14ce357a67a20251276475241f574cc5e2ee
+\ No newline at end of file