Fix Adobe RGB color space in Skia

Our runtime definition of the XYZ matrix was fairly inaccurate. It also
didn't round-trip through ICC fixed point correctly. Now, constructing the
color space at runtime produces exactly the same matrix as constructing
the space from the ICC profile. And the values can then be serialized back
to ICC exactly. This eliminates the need for the snapping logic, too.

Bug: skia:
Change-Id: I69f4a9bfec3eeef153935e21ab3a0630794b1607
Reviewed-on: https://skia-review.googlesource.com/84840
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>

4 files changed, 24 insertions, 1 deletions

diff --git a/resources/icc_profiles/AdobeRGB1998.icc b/resources/icc_profiles/AdobeRGB1998.icc
new file mode 100644
index 0000000000..a79f576b59
--- /dev/null
+++ b/resources/icc_profiles/AdobeRGB1998.icc
diff --git a/src/core/SkColorSpace.cpp b/src/core/SkColorSpace.cpp
index e9efffd96d..235518d3b9 100644
--- a/src/core/SkColorSpace.cpp
+++ b/src/core/SkColorSpace.cpp
@@ -119,6 +119,7 @@ sk_sp<SkColorSpace> SkColorSpace_Base::MakeRGB(SkGammaNamed gammaNamed, const Sk
                 return SkColorSpace::MakeSRGB();
             }
             break;
+#ifdef SK_SUPPORT_LEGACY_ADOBE_XYZ
         case k2Dot2Curve_SkGammaNamed:
             if (xyz_almost_equal(toXYZD50, gAdobeRGB_toXYZD50)) {
                 SkMatrix44 adobe44(SkMatrix44::kUninitialized_Constructor);
@@ -126,6 +127,7 @@ sk_sp<SkColorSpace> SkColorSpace_Base::MakeRGB(SkGammaNamed gammaNamed, const Sk
                 return sk_sp<SkColorSpace>(new SkColorSpace_XYZ(k2Dot2Curve_SkGammaNamed, adobe44));
             }
             break;
+#endif
         case kLinear_SkGammaNamed:
             if (xyz_almost_equal(toXYZD50, gSRGB_toXYZD50)) {
                 return SkColorSpace::MakeSRGBLinear();
diff --git a/src/core/SkColorSpacePriv.h b/src/core/SkColorSpacePriv.h
index 64fe31fce3..b0a8c1dcbc 100644
--- a/src/core/SkColorSpacePriv.h
+++ b/src/core/SkColorSpacePriv.h
@@ -10,6 +10,7 @@
 #include <math.h>
 
 #include "SkColorSpace_Base.h"
+#include "SkFixed.h"
 
 #define SkColorSpacePrintf(...)
 
@@ -20,9 +21,19 @@ static constexpr float gSRGB_toXYZD50[] {
 };
 
 static constexpr float gAdobeRGB_toXYZD50[] {
+#ifdef SK_SUPPORT_LEGACY_ADOBE_XYZ
     0.6097559f, 0.2052401f, 0.1492240f, // Rx, Gx, Bx
     0.3111242f, 0.6256560f, 0.0632197f, // Ry, Gy, Gz
     0.0194811f, 0.0608902f, 0.7448387f, // Rz, Gz, Bz
+#else
+    // ICC fixed-point (16.16) repesentation of:
+    // 0.60974, 0.20528, 0.14919,
+    // 0.31111, 0.62567, 0.06322,
+    // 0.01947, 0.06087, 0.74457,
+    SkFixedToFloat(0x9c18), SkFixedToFloat(0x348d), SkFixedToFloat(0x2631), // Rx, Gx, Bx
+    SkFixedToFloat(0x4fa5), SkFixedToFloat(0xa02c), SkFixedToFloat(0x102f), // Ry, Gy, Gz
+    SkFixedToFloat(0x04fc), SkFixedToFloat(0x0f95), SkFixedToFloat(0xbe9c), // Rz, Gz, Bz
+#endif
 };
 
 static constexpr float gDCIP3_toXYZD50[] {
diff --git a/tests/ICCTest.cpp b/tests/ICCTest.cpp
index cfe4dc04a0..378a430dc0 100644
--- a/tests/ICCTest.cpp
+++ b/tests/ICCTest.cpp
@@ -98,6 +98,16 @@ DEF_TEST(ICC_IsNumericalTransferFn, r) {
     test_is_numerical_transfer_fn(r, upperRight.get(), false, referenceFn);
 }
 
+DEF_TEST(ICC_Adobe, r) {
+    // Test that the color spaces produced by our procedural Adobe factory, and the official
+    // Adobe ICC profile match exactly.
+    sk_sp<SkData> data = GetResourceAsData("icc_profiles/AdobeRGB1998.icc");
+    sk_sp<SkColorSpace> fromIcc = SkColorSpace::MakeICC(data->data(), data->size());
+    sk_sp<SkColorSpace> procedural = SkColorSpace::MakeRGB(g2Dot2_TransferFn,
+                                                           SkColorSpace::kAdobeRGB_Gamut);
+    REPORTER_ASSERT(r, SkColorSpace::Equals(fromIcc.get(), procedural.get()));
+}
+
 static inline void test_write_icc(skiatest::Reporter* r, const SkColorSpaceTransferFn& fn,
                                   const SkMatrix44& toXYZD50, bool writeToFile) {
     sk_sp<SkData> profile = SkICC::WriteToICC(fn, toXYZD50);
@@ -124,7 +134,7 @@ DEF_TEST(ICC_WriteICC, r) {
     adobeMatrix.set3x3RowMajorf(gAdobeRGB_toXYZD50);
     // TODO: Restore this test once we fix our Adobe matrix to be based on the decoded ICC
     // fixed point values, and once we use a rounding conversion to fixed-point.
-//    test_write_icc(r, adobeFn, adobeMatrix, false);
+    test_write_icc(r, adobeFn, adobeMatrix, false);
 
     SkColorSpaceTransferFn srgbFn;
     srgbFn.fA = 1.0f / 1.055f;