return 4x4 matrix from SkColorSpace

tests/ColorSpaceTest.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 "SkColorSpace.h"
 #include "Test.h"
 
 #include "png.h"
 
+static bool almost_equal(float a, float b) {
+    return SkTAbs(a - b) < 0.001f;
+}
+
+static void test_space(skiatest::Reporter* r, SkColorSpace* space,
+                       const float red[], const float green[], const float blue[],
+                       const float expectedGammas[]) {
+#ifdef SK_DEBUG
+    const SkColorSpace::SkGammas& gammas = space->gammas();
+    REPORTER_ASSERT(r, almost_equal(expectedGammas[0], gammas.red()));
+    REPORTER_ASSERT(r, almost_equal(expectedGammas[1], gammas.green()));
+    REPORTER_ASSERT(r, almost_equal(expectedGammas[2], gammas.blue()));
+#endif
+
+    SkMatrix44 mat = space->xyz();
+    const float src[] = {
+        1, 0, 0, 1,
+        0, 1, 0, 1,
+        0, 0, 1, 1,
+    };
+    float dst[4];
+    for (int i = 0; i < 3; ++i) {
+        mat.mapScalars(&src[i*4], dst);
+        REPORTER_ASSERT(r, almost_equal(red[i],   dst[0]));
+        REPORTER_ASSERT(r, almost_equal(green[i], dst[1]));
+        REPORTER_ASSERT(r, almost_equal(blue[i],  dst[2]));
+    }
+}
+
+DEF_TEST(ColorSpace_sRGB, r) {
+    const float srgb_r[] = { 0.4358f, 0.2224f, 0.0139f };
+    const float srgb_g[] = { 0.3853f, 0.7170f, 0.0971f };
+    const float srgb_b[] = { 0.1430f, 0.0606f, 0.7139f };
+    const float srgb_gamma[] = { 2.2f, 2.2f, 2.2f };
+    test_space(r, SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named).get(),
+               srgb_r, srgb_g, srgb_b, srgb_gamma);
+
+}
+
 static SkStreamAsset* resource(const char path[]) {
     SkString fullPath = GetResourcePath(path);
     return SkStream::NewFromFile(fullPath.c_str());
 }
 
-static bool almost_equal(float a, float b) {
-    return SkTAbs(a - b) < 0.001f;
-}
-
 DEF_TEST(ColorSpaceParsePngICCProfile, r) {
     SkAutoTDelete<SkStream> stream(resource("color_wheel_with_profile.png"));
     REPORTER_ASSERT(r, nullptr != stream);
     if (!stream) {
         return;
     }
 
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(stream.release()));
     REPORTER_ASSERT(r, nullptr != codec);
 
 #if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6)
     SkColorSpace* colorSpace = codec->getColorSpace();
     REPORTER_ASSERT(r, nullptr != colorSpace);
 
-    // The color profile that we have extracted has represents gamma with a lookup table.
-    // So we expect the gamma value to be zero.
-#ifdef SK_DEBUG
-    const SkColorSpace::SkGammas& gammas = colorSpace->gammas();
-    REPORTER_ASSERT(r, 0.0f == gammas.red());
-    REPORTER_ASSERT(r, 0.0f == gammas.green());
-    REPORTER_ASSERT(r, 0.0f == gammas.blue());
-#endif
-
-    // These nine values were extracted from the color profile in isolation (before
-    // we embedded it in the png).  Here we check that we still extract the same values.
-    SkFloat3x3 xyz = colorSpace->xyz();
-    REPORTER_ASSERT(r, almost_equal(0.436066f, xyz.fMat[0]));
-    REPORTER_ASSERT(r, almost_equal(0.222488f, xyz.fMat[1]));
-    REPORTER_ASSERT(r, almost_equal(0.013916f, xyz.fMat[2]));
-    REPORTER_ASSERT(r, almost_equal(0.385147f, xyz.fMat[3]));
-    REPORTER_ASSERT(r, almost_equal(0.716873f, xyz.fMat[4]));
-    REPORTER_ASSERT(r, almost_equal(0.0970764f, xyz.fMat[5]));
-    REPORTER_ASSERT(r, almost_equal(0.143066f, xyz.fMat[6]));
-    REPORTER_ASSERT(r, almost_equal(0.0606079f, xyz.fMat[7]));
-    REPORTER_ASSERT(r, almost_equal(0.714096f, xyz.fMat[8]));
+    const float red[] = { 0.436066f, 0.222488f, 0.013916f };
+    const float green[] = { 0.385147f, 0.716873f, 0.0970764f };
+    const float blue[] = { 0.143066f, 0.0606079f, 0.714096f };
+    const float gamma[] = { 0, 0, 0 };  // table-based gamma returns 0 from this its float-getter
+    test_space(r, colorSpace, red, green, blue, gamma);
 #endif
 }
 
 DEF_TEST(ColorSpaceParseJpegICCProfile, r) {
     SkAutoTDelete<SkStream> stream(resource("icc-v2-gbr.jpg"));
     REPORTER_ASSERT(r, nullptr != stream);
     if (!stream) {
         return;
     }
 
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(stream.release()));
     REPORTER_ASSERT(r, nullptr != codec);
     if (!codec) {
         return;
     }
 
     SkColorSpace* colorSpace = codec->getColorSpace();
     REPORTER_ASSERT(r, nullptr != colorSpace);
 
-    // It's important to use almost equal here.  This profile sets gamma as
-    // 563 / 256, which actually comes out to about 2.19922.
-#ifdef SK_DEBUG
-    const SkColorSpace::SkGammas& gammas = colorSpace->gammas();
-    REPORTER_ASSERT(r, almost_equal(2.2f, gammas.red()));
-    REPORTER_ASSERT(r, almost_equal(2.2f, gammas.green()));
-    REPORTER_ASSERT(r, almost_equal(2.2f, gammas.blue()));
-#endif
-
-    // These nine values were extracted from the color profile.  Until we know any
-    // better, we'll assume these are the right values and test that we continue
-    // to extract them properly.
-    SkFloat3x3 xyz = colorSpace->xyz();
-    REPORTER_ASSERT(r, almost_equal(0.385117f, xyz.fMat[0]));
-    REPORTER_ASSERT(r, almost_equal(0.716904f, xyz.fMat[1]));
-    REPORTER_ASSERT(r, almost_equal(0.0970612f, xyz.fMat[2]));
-    REPORTER_ASSERT(r, almost_equal(0.143051f, xyz.fMat[3]));
-    REPORTER_ASSERT(r, almost_equal(0.0606079f, xyz.fMat[4]));
-    REPORTER_ASSERT(r, almost_equal(0.713913f, xyz.fMat[5]));
-    REPORTER_ASSERT(r, almost_equal(0.436035f, xyz.fMat[6]));
-    REPORTER_ASSERT(r, almost_equal(0.222488f, xyz.fMat[7]));
-    REPORTER_ASSERT(r, almost_equal(0.013916f, xyz.fMat[8]));
+    const float red[] = { 0.385117f, 0.716904f, 0.0970612f };
+    const float green[] = { 0.143051f, 0.0606079f, 0.713913f };
+    const float blue[] = { 0.436035f, 0.222488f, 0.013916f };
+    const float gamma[] = { 2.2f, 2.2f, 2.2f };
+    test_space(r, colorSpace, red, green, blue, gamma);
 }