Add SkDefaultXform as a catch-all to handle color conversions
I'd like to start optimizing the common case for color xforms,
but before doing that, I think it makes sense to have correct
code to support all xforms.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2038823002
Review-Url: https://codereview.chromium.org/2038823002
diff --git a/tests/ColorSpaceXformTest.cpp b/tests/ColorSpaceXformTest.cpp
new file mode 100644
index 0000000..220509b
--- /dev/null
+++ b/tests/ColorSpaceXformTest.cpp
@@ -0,0 +1,103 @@
+/*
+ * 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 "SkColorPriv.h"
+#include "SkColorSpace.h"
+#include "SkColorSpace_Base.h"
+#include "SkColorSpaceXform.h"
+#include "Test.h"
+
+class ColorSpaceXformTest {
+public:
+ static SkDefaultXform* CreateDefaultXform(const sk_sp<SkGammas>& srcGamma,
+ const SkMatrix44& srcToDst, const sk_sp<SkGammas>& dstGamma) {
+ return new SkDefaultXform(srcGamma, srcToDst, dstGamma);
+ }
+};
+
+static void test_xform(skiatest::Reporter* r, const sk_sp<SkGammas>& gammas) {
+ // Arbitrary set of 10 pixels
+ constexpr int width = 10;
+ constexpr uint32_t srcPixels[width] = {
+ 0xFFABCDEF, 0xFF146829, 0xFF382759, 0xFF184968, 0xFFDE8271,
+ 0xFF32AB52, 0xFF0383BC, 0xFF000000, 0xFFFFFFFF, 0xFFDDEEFF, };
+ uint32_t dstPixels[width];
+
+ // Identity matrix
+ SkMatrix44 srcToDst = SkMatrix44::I();
+
+ // Create and perform xform
+ std::unique_ptr<SkColorSpaceXform> xform(
+ ColorSpaceXformTest::CreateDefaultXform(gammas, srcToDst, gammas));
+ xform->xform_RGBA_8888(dstPixels, srcPixels, width);
+
+ // Since the matrix is the identity, and the gamma curves match, the pixels
+ // should be unchanged.
+ for (int i = 0; i < width; i++) {
+ // TODO (msarett):
+ // As the implementation changes, we may want to use a tolerance here.
+ REPORTER_ASSERT(r, ((srcPixels[i] >> 0) & 0xFF) == SkGetPackedR32(dstPixels[i]));
+ REPORTER_ASSERT(r, ((srcPixels[i] >> 8) & 0xFF) == SkGetPackedG32(dstPixels[i]));
+ REPORTER_ASSERT(r, ((srcPixels[i] >> 16) & 0xFF) == SkGetPackedB32(dstPixels[i]));
+ REPORTER_ASSERT(r, ((srcPixels[i] >> 24) & 0xFF) == SkGetPackedA32(dstPixels[i]));
+ }
+}
+
+DEF_TEST(ColorSpaceXform_TableGamma, r) {
+ // Lookup-table based gamma curves
+ SkGammaCurve red, green, blue;
+ constexpr size_t tableSize = 10;
+ red.fTable = std::unique_ptr<float[]>(new float[tableSize]);
+ green.fTable = std::unique_ptr<float[]>(new float[tableSize]);
+ blue.fTable = std::unique_ptr<float[]>(new float[tableSize]);
+ red.fTableSize = green.fTableSize = blue.fTableSize = 10;
+ red.fTable[0] = green.fTable[0] = blue.fTable[0] = 0.00f;
+ red.fTable[1] = green.fTable[1] = blue.fTable[1] = 0.05f;
+ red.fTable[2] = green.fTable[2] = blue.fTable[2] = 0.10f;
+ red.fTable[3] = green.fTable[3] = blue.fTable[3] = 0.15f;
+ red.fTable[4] = green.fTable[4] = blue.fTable[4] = 0.25f;
+ red.fTable[5] = green.fTable[5] = blue.fTable[5] = 0.35f;
+ red.fTable[6] = green.fTable[6] = blue.fTable[6] = 0.45f;
+ red.fTable[7] = green.fTable[7] = blue.fTable[7] = 0.60f;
+ red.fTable[8] = green.fTable[8] = blue.fTable[8] = 0.75f;
+ red.fTable[9] = green.fTable[9] = blue.fTable[9] = 1.00f;
+ sk_sp<SkGammas> gammas =
+ sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
+ test_xform(r, gammas);
+}
+
+DEF_TEST(ColorSpaceXform_ParametricGamma, r) {
+ // Parametric gamma curves
+ SkGammaCurve red, green, blue;
+
+ // Interval, switch xforms at 0.5f
+ red.fD = green.fD = blue.fD = 0.5f;
+
+ // First equation, Y = 0.5f * X
+ red.fE = green.fE = blue.fE = 0.5f;
+
+ // Second equation, Y = ((1.0f * X) + 0.0f) ^ 3.0f + 0.125f
+ // Note that the function is continuous:
+ // 0.5f * 0.5f = ((1.0f * 0.5f) + 0.0f) ^ 3.0f + 0.125f = 0.25f
+ red.fA = green.fA = blue.fA = 1.0f;
+ red.fB = green.fB = blue.fB = 0.0f;
+ red.fC = green.fC = blue.fC = 0.125f;
+ red.fG = green.fG = blue.fG = 3.0f;
+ sk_sp<SkGammas> gammas = sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
+ test_xform(r, gammas);
+}
+
+DEF_TEST(ColorSpaceXform_ExponentialGamma, r) {
+ // Exponential gamma curves
+ SkGammaCurve red, green, blue;
+ red.fValue = green.fValue = blue.fValue = 4.0f;
+ sk_sp<SkGammas> gammas =
+ sk_make_sp<SkGammas>(std::move(red), std::move(green), std::move(blue));
+ test_xform(r, gammas);
+}