Cache dst LUTs in SkColorSpaceXform

tests/ColorSpaceXformTest.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkCodec.h"
 #include "SkCodecPriv.h"
@@ skipping 12 matching lines @@
 
         // Use special testing entry point, so we don't skip the xform, even though src == dst.
         return SlowIdentityXform(space.get());
     }
 };
 
 static bool almost_equal(int x, int y) {
     return SkTAbs(x - y) <= 1;
 }
 
-static void test_identity_xform(skiatest::Reporter* r, const sk_sp<SkGammas>& gammas) {
+static void test_identity_xform(skiatest::Reporter* r, const sk_sp<SkGammas>& gammas,
+                                bool repeat) {
     // Arbitrary set of 10 pixels
     constexpr int width = 10;
     constexpr uint32_t srcPixels[width] = {
             0xFFABCDEF, 0xFF146829, 0xFF382759, 0xFF184968, 0xFFDE8271,
             0xFF32AB52, 0xFF0383BC, 0xFF000102, 0xFFFFFFFF, 0xFFDDEEFF, };
     uint32_t dstPixels[width];
 
     // Create and perform an identity xform.
     std::unique_ptr<SkColorSpaceXform> xform = ColorSpaceXformTest::CreateIdentityXform(gammas);
     bool result = xform->apply(select_xform_format(kN32_SkColorType), dstPixels,
                                SkColorSpaceXform::kBGRA_8888_ColorFormat, srcPixels, width,
                                kOpaque_SkAlphaType);
     REPORTER_ASSERT(r, result);
 
     // Since the src->dst matrix is the identity, and the gamma curves match,
     // the pixels should be unchanged.
     for (int i = 0; i < width; i++) {
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >>  0) & 0xFF),
                                         SkGetPackedB32(dstPixels[i])));
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >>  8) & 0xFF),
                                         SkGetPackedG32(dstPixels[i])));
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >> 16) & 0xFF),
                                         SkGetPackedR32(dstPixels[i])));
         REPORTER_ASSERT(r, almost_equal(((srcPixels[i] >> 24) & 0xFF),
                                         SkGetPackedA32(dstPixels[i])));
     }
+
+    if (repeat) {
+        // We should cache part of the transform after the run.  So it is interesting
+        // to make sure it still runs correctly the second time.
+        test_identity_xform(r, gammas, false);
+    }
 }
 
 DEF_TEST(ColorSpaceXform_TableGamma, r) {
     // Lookup-table based gamma curves
     constexpr size_t tableSize = 10;
     void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize);
     sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
     gammas->fRedType = gammas->fGreenType = gammas->fBlueType = SkGammas::Type::kTable_Type;
     gammas->fRedData.fTable.fSize = gammas->fGreenData.fTable.fSize =
             gammas->fBlueData.fTable.fSize = tableSize;
     gammas->fRedData.fTable.fOffset = gammas->fGreenData.fTable.fOffset =
             gammas->fBlueData.fTable.fOffset = 0;
     float* table = SkTAddOffset<float>(memory, sizeof(SkGammas));
 
     table[0] = 0.00f;
     table[1] = 0.05f;
     table[2] = 0.10f;
     table[3] = 0.15f;
     table[4] = 0.25f;
     table[5] = 0.35f;
     table[6] = 0.45f;
     table[7] = 0.60f;
     table[8] = 0.75f;
     table[9] = 1.00f;
-    test_identity_xform(r, gammas);
+    test_identity_xform(r, gammas, true);
 }
 
 DEF_TEST(ColorSpaceXform_ParametricGamma, r) {
     // Parametric gamma curves
     void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(SkColorSpaceTransferFn));
     sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
     gammas->fRedType = gammas->fGreenType = gammas->fBlueType = SkGammas::Type::kParam_Type;
     gammas->fRedData.fParamOffset = gammas->fGreenData.fParamOffset =
             gammas->fBlueData.fParamOffset = 0;
     SkColorSpaceTransferFn* params = SkTAddOffset<SkColorSpaceTransferFn>
             (memory, sizeof(SkGammas));
 
     // Interval, switch xforms at 0.0031308f
     params->fD = 0.04045f;
 
     // First equation:
     params->fE = 1.0f / 12.92f;
     params->fF = 0.0f;
 
     // Second equation:
     // Note that the function is continuous (it's actually sRGB).
     params->fA = 1.0f / 1.055f;
     params->fB = 0.055f / 1.055f;
     params->fC = 0.0f;
     params->fG = 2.4f;
-    test_identity_xform(r, gammas);
+    test_identity_xform(r, gammas, true);
 }
 
 DEF_TEST(ColorSpaceXform_ExponentialGamma, r) {
     // Exponential gamma curves
     sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new SkGammas());
     gammas->fRedType = gammas->fGreenType = gammas->fBlueType = SkGammas::Type::kValue_Type;
     gammas->fRedData.fValue = gammas->fGreenData.fValue = gammas->fBlueData.fValue = 1.4f;
-    test_identity_xform(r, gammas);
+    test_identity_xform(r, gammas, true);
 }
 
 DEF_TEST(ColorSpaceXform_NamedGamma, r) {
     sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new SkGammas());
     gammas->fRedType = gammas->fGreenType = gammas->fBlueType = SkGammas::Type::kNamed_Type;
     gammas->fRedData.fNamed = kSRGB_SkGammaNamed;
     gammas->fGreenData.fNamed = k2Dot2Curve_SkGammaNamed;
     gammas->fBlueData.fNamed = kLinear_SkGammaNamed;
-    test_identity_xform(r, gammas);
+    test_identity_xform(r, gammas, true);
 }
 
 DEF_TEST(ColorSpaceXform_NonMatchingGamma, r) {
     constexpr size_t tableSize = 10;
     void* memory = sk_malloc_throw(sizeof(SkGammas) + sizeof(float) * tableSize +
                                    sizeof(SkColorSpaceTransferFn));
     sk_sp<SkGammas> gammas = sk_sp<SkGammas>(new (memory) SkGammas());
 
     float* table = SkTAddOffset<float>(memory, sizeof(SkGammas));
     table[0] = 0.00f;
@@ skipping 20 matching lines @@
     gammas->fRedType = SkGammas::Type::kValue_Type;
     gammas->fRedData.fValue = 1.2f;
 
     gammas->fGreenType = SkGammas::Type::kTable_Type;
     gammas->fGreenData.fTable.fSize = tableSize;
     gammas->fGreenData.fTable.fOffset = 0;
 
     gammas->fBlueType = SkGammas::Type::kParam_Type;
     gammas->fBlueData.fParamOffset = sizeof(float) * tableSize;
 
-    test_identity_xform(r, gammas);
+    test_identity_xform(r, gammas, true);
 }
 
 DEF_TEST(ColorSpaceXform_applyCLUTMemoryAccess, r) {
     // buffers larger than 1024 (or 256 in GOOGLE3) will force ColorSpaceXform_Base::apply()
     // to heap-allocate a buffer that is used for CLUT application, and this test is here to
     // ensure that it no longer causes potential invalid memory accesses when this happens
     const size_t len = 2048;
     SkAutoTMalloc<uint32_t> src(len);
     SkAutoTMalloc<uint32_t> dst(len);
     for (uint32_t i = 0; i < len; ++i) {
         src[i] = i;
     }
     // this ICC profile has a CLUT in it
     const SkString filename(GetResourcePath("icc_profiles/upperRight.icc"));
     sk_sp<SkData> iccData = SkData::MakeFromFileName(filename.c_str());
     REPORTER_ASSERT_MESSAGE(r, iccData, "upperRight.icc profile required for test");
     sk_sp<SkColorSpace> srcSpace = SkColorSpace::NewICC(iccData->bytes(), iccData->size());
     sk_sp<SkColorSpace> dstSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
     auto xform = SkColorSpaceXform::New(srcSpace.get(), dstSpace.get());
     bool result = xform->apply(SkColorSpaceXform::kRGBA_8888_ColorFormat, dst.get(),
                                SkColorSpaceXform::kRGBA_8888_ColorFormat, src.get(), len,
                                kUnpremul_SkAlphaType);
     REPORTER_ASSERT(r, result);
 }