expand unitests for color4f

tests/SkColor4fTest.cpp

Index: tests/SkColor4fTest.cpp
diff --git a/tests/SkColor4fTest.cpp b/tests/SkColor4fTest.cpp
index b09b0c479a055907271bd753bec4737f061de5e6..6069246bc5144df10d87b4640c4d0d12e25d9009 100644
--- a/tests/SkColor4fTest.cpp
+++ b/tests/SkColor4fTest.cpp
@@ -6,11 +6,30 @@
  */
 
 #include "SkColor.h"
-#include "SkShader.h"
 #include "SkColorMatrixFilter.h"
+#include "SkGradientShader.h"
+#include "SkImage.h"
+#include "SkShader.h"
+
 #include "Test.h"
 #include "SkRandom.h"
 
+const float kTolerance = 1.0f / (1 << 20);
+
+static bool nearly_equal(float a, float b, float tol = kTolerance) {
+    SkASSERT(tol >= 0);
+    return fabsf(a - b) <= tol;
+}
+
+static bool nearly_equal(const SkPM4f a, const SkPM4f& b, float tol = kTolerance) {
+    for (int i = 0; i < 4; ++i) {
+        if (!nearly_equal(a.fVec[i], b.fVec[i], tol)) {
+            return false;
+        }
+    }
+    return true;
+}
+
 DEF_TEST(SkColor4f_FromColor, reporter) {
     const struct {
         SkColor     fC;
@@ -31,12 +50,7 @@ DEF_TEST(SkColor4f_FromColor, reporter) {
     }
 }
 
-static bool nearly_equal(float a, float b) {
-    const float kTolerance = 1.0f / (1 << 20);
-    return fabsf(a - b) < kTolerance;
-}
-
-DEF_TEST(SkColor4f_premul, reporter) {
+DEF_TEST(Color4f_premul, reporter) {
     SkRandom rand;
 
     for (int i = 0; i < 1000000; ++i) {
@@ -60,3 +74,119 @@ DEF_TEST(SkColor4f_premul, reporter) {
         REPORTER_ASSERT(reporter, nearly_equal(pm4.fVec[SK_B_INDEX], c4.fA * c4.fB));
     }
 }
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+static SkShader* make_color() { return SkShader::CreateColorShader(0xFFBB8855); }
+
+static SkShader* make_image() {
+    const SkImageInfo info = SkImageInfo::MakeN32Premul(2, 2);
+    const SkPMColor pixels[] {
+        SkPackARGB32(0xFF, 0xBB, 0x88, 0x55),
+        SkPackARGB32(0xFF, 0xBB, 0x88, 0x55),
+        SkPackARGB32(0xFF, 0xBB, 0x88, 0x55),
+        SkPackARGB32(0xFF, 0xBB, 0x88, 0x55),
+    };
+    SkAutoTUnref<SkImage> image(SkImage::NewRasterCopy(info, pixels, sizeof(SkPMColor) * 2));
+    return image->newShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
+}
+
+static SkShader* make_grad() {
+    const SkPoint pts[] {{ 0, 0 }, { 100, 100 }};
+    const SkColor colors[] { SK_ColorRED, SK_ColorBLUE };
+    return SkGradientShader::CreateLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode);
+}
+
+static void compare_spans(const SkPM4f span4f[], const SkPMColor span4b[], int count,
+                          skiatest::Reporter* reporter) {
+    for (int i = 0; i < count; ++i) {
+        SkPM4f c0 = SkPM4f::FromPMColor(span4b[i]);
+        SkPM4f c1 = span4f[i];
+        REPORTER_ASSERT(reporter, nearly_equal(c0, c1, 1.0f/255));
+    }
+}
+
+DEF_TEST(Color4f_shader, reporter) {
+    struct {
+        SkShader*   (*fFact)();
+        bool        fSupports4f;
+    } recs[] = {
+        { make_color, true },
+        { make_grad,  false },
+        { make_image, false },
+    };
+
+    SkPaint paint;
+    for (const auto& rec : recs) {
+        uint32_t storage[200];
+        paint.setShader(rec.fFact())->unref();
+        SkASSERT(paint.getShader()->contextSize() <= sizeof(storage));
+        SkShader::Context* ctx = paint.getShader()->createContext({paint, SkMatrix::I(), nullptr},
+                                                                  storage);
+        REPORTER_ASSERT(reporter, ctx->supports4f() == rec.fSupports4f);
+        if (ctx->supports4f()) {
+            const int N = 100;
+            SkPM4f buffer4f[N];
+            ctx->shadeSpan4f(0, 0, buffer4f, N);
+            SkPMColor buffer4b[N];
+            ctx->shadeSpan(0, 0, buffer4b, N);
+            compare_spans(buffer4f, buffer4b, N, reporter);
+        }
+        ctx->SkShader::Context::~Context();
+    }
+}
+
+static SkColorFilter* make_mode_cf() {
+    return SkColorFilter::CreateModeFilter(0xFFBB8855, SkXfermode::kPlus_Mode);
+}
+
+static SkColorFilter* make_mx_cf() {
+    const float mx[] = {
+        0.5f, 0,    0, 0, 0.1f,
+        0,    0.5f, 0, 0, 0.2f,
+        0,    0,    1, 0, -0.1f,
+        0,    0,    0, 1, 0,
+    };
+    return SkColorMatrixFilter::Create(mx);
+}
+
+static SkColorFilter* make_compose_cf() {
+    SkAutoTUnref<SkColorFilter> cf0(make_mode_cf());
+    SkAutoTUnref<SkColorFilter> cf1(make_mx_cf());
+    return SkColorFilter::CreateComposeFilter(cf0, cf1);
+}
+
+DEF_TEST(Color4f_colorfilter, reporter) {
+    struct {
+        SkColorFilter* (*fFact)();
+        bool           fSupports4f;
+    } recs[] = {
+        { make_mode_cf,     false },
+        { make_mx_cf,       true },
+        { make_compose_cf,  false },
+    };
+
+    // prepare the src
+    const int N = 100;
+    SkPMColor src4b[N];
+    SkPM4f    src4f[N];
+    SkRandom rand;
+    for (int i = 0; i < N; ++i) {
+        src4b[i] = SkPreMultiplyColor(rand.nextU());
+        src4f[i] = SkPM4f::FromPMColor(src4b[i]);
+    }
+    // confirm that our srcs are (nearly) equal
+    compare_spans(src4f, src4b, N, reporter);
+
+    for (const auto& rec : recs) {
+        SkAutoTUnref<SkColorFilter> filter(rec.fFact());
+        REPORTER_ASSERT(reporter, filter->supports4f() == rec.fSupports4f);
+        if (filter->supports4f()) {
+            SkPMColor dst4b[N];
+            filter->filterSpan(src4b, N, dst4b);
+            SkPM4f dst4f[N];
+            filter->filterSpan4f(src4f, N, dst4f);
+            compare_spans(dst4f, dst4b, N, reporter);
+        }
+    }
+}