Fix swapped interpretation of c and e in SkColorSpace_ICC

The ICC errata supports the opposite of what we do.
http://www.color.org/icc_specs2.xalter

TBR=reed@google.com

BUG=skia:

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD

Change-Id: I18ace7f312926b264e624c30d8cb983eff5c434b
Reviewed-on: https://skia-review.googlesource.com/6277
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

1 files changed, 14 insertions, 14 deletions

diff --git a/src/core/SkColorSpacePriv.h b/src/core/SkColorSpacePriv.h
index 32981ae875..f1ef8dc6d6 100644
--- a/src/core/SkColorSpacePriv.h
+++ b/src/core/SkColorSpacePriv.h
@@ -45,7 +45,7 @@ static inline bool is_valid_transfer_fn(const SkColorSpaceTransferFn& coeffs) {
         }
     }
 
-    if (coeffs.fD == 1.0f) {
+    if (coeffs.fD >= 1.0f) {
         // Y = eX + f          for always
         if (0.0f == coeffs.fE) {
             SkColorSpacePrintf("E is zero, constant transfer function is "
@@ -54,13 +54,13 @@ static inline bool is_valid_transfer_fn(const SkColorSpaceTransferFn& coeffs) {
         }
     }
 
-    if ((0.0f == coeffs.fA || 0.0f == coeffs.fG) && 0.0f == coeffs.fE) {
+    if ((0.0f == coeffs.fA || 0.0f == coeffs.fG) && 0.0f == coeffs.fC) {
         SkColorSpacePrintf("A or G, and E are zero, constant transfer function "
                            "is nonsense");
         return false;
     }
 
-    if (coeffs.fE < 0.0f) {
+    if (coeffs.fC < 0.0f) {
         SkColorSpacePrintf("Transfer function must be increasing");
         return false;
     }
@@ -74,13 +74,13 @@ static inline bool is_valid_transfer_fn(const SkColorSpaceTransferFn& coeffs) {
 }
 
 static inline bool is_almost_srgb(const SkColorSpaceTransferFn& coeffs) {
-    return color_space_almost_equal(0.9479f, coeffs.fA) &&
-           color_space_almost_equal(0.0521f, coeffs.fB) &&
-           color_space_almost_equal(0.0000f, coeffs.fC) &&
-           color_space_almost_equal(0.0405f, coeffs.fD) &&
-           color_space_almost_equal(0.0774f, coeffs.fE) &&
-           color_space_almost_equal(0.0000f, coeffs.fF) &&
-           color_space_almost_equal(2.4000f, coeffs.fG);
+    return color_space_almost_equal(1.0f / 1.055f,   coeffs.fA) &&
+           color_space_almost_equal(0.055f / 1.055f, coeffs.fB) &&
+           color_space_almost_equal(1.0f / 12.92f,   coeffs.fC) &&
+           color_space_almost_equal(0.04045f,        coeffs.fD) &&
+           color_space_almost_equal(0.00000f,        coeffs.fE) &&
+           color_space_almost_equal(0.00000f,        coeffs.fF) &&
+           color_space_almost_equal(2.40000f,        coeffs.fG);
 }
 
 static inline bool is_almost_2dot2(const SkColorSpaceTransferFn& coeffs) {
@@ -109,9 +109,9 @@ static inline bool named_to_parametric(SkColorSpaceTransferFn* coeffs,
         case kSRGB_SkGammaNamed:
             coeffs->fA = 1.0f / 1.055f;
             coeffs->fB = 0.055f / 1.055f;
-            coeffs->fC = 0.0f;
+            coeffs->fC = 1.0f / 12.92f;
             coeffs->fD = 0.04045f;
-            coeffs->fE = 1.0f / 12.92f;
+            coeffs->fE = 0.0f;
             coeffs->fF = 0.0f;
             coeffs->fG = 2.4f;
             return true;
@@ -121,11 +121,11 @@ static inline bool named_to_parametric(SkColorSpaceTransferFn* coeffs,
         case kLinear_SkGammaNamed:
             coeffs->fA = 0.0f;
             coeffs->fB = 0.0f;
-            coeffs->fC = 0.0f;
+            coeffs->fC = 1.0f;
             // Make sure that we use the linear segment of the transfer function even
             // when the x-value is 1.0f.
             coeffs->fD = add_epsilon(1.0f);
-            coeffs->fE = 1.0f;
+            coeffs->fE = 0.0f;
             coeffs->fF = 0.0f;
             coeffs->fG = 0.0f;
             return true;