expand unitests for color4f

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1622893002

TBR=

Review URL: https://codereview.chromium.org/1622893002

include/core/SkColor.h

@@ -169,6 +169,8 @@ struct SkPM4f {
     float fVec[4];
 
     float a() const { return fVec[SK_A32_SHIFT/8]; }
+
+    static SkPM4f FromPMColor(SkPMColor);
 };
 
 /*

include/core/SkColorFilter.h

@@ -81,6 +81,10 @@ public:
     */
     virtual uint32_t getFlags() const { return 0; }
 
+    bool supports4f() const {
+        return SkToBool(this->getFlags() & kSupports4f_Flag);
+    }
+
     /**
      *  If this subclass can optimally createa composition with the inner filter, return it as
      *  a new filter (which the caller must unref() when it is done). If no such optimization

include/core/SkShader.h

@@ -121,6 +121,10 @@ public:
          */
         virtual uint32_t getFlags() const { return 0; }
 
+        bool supports4f() const {
+            return SkToBool(this->getFlags() & kSupports4f_Flag);
+        }
+
         /**
          *  Called for each span of the object being drawn. Your subclass should
          *  set the appropriate colors (with premultiplied alpha) that correspond

src/core/SkColor.cpp

@@ -104,9 +104,10 @@ SkColor SkHSVToColor(U8CPU a, const SkScalar hsv[3]) {
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 #include "SkNx.h"
 
-SkColor4f SkColor4f::Pin(float a, float r, float g, float b) {
-    SkColor4f c4;
-    Sk4f::Min(Sk4f::Max(Sk4f(a, r, g, b), Sk4f(0)), Sk4f(1)).store(c4.vec());
+SkPM4f SkPM4f::FromPMColor(SkPMColor c) {
+    Sk4f value = SkNx_cast<float>(Sk4b::Load((const uint8_t*)&c));
+    SkPM4f c4;
+    (value * Sk4f(1.0f / 255)).store(c4.fVec);
     return c4;
 }
 
@@ -117,6 +118,12 @@ SkColor4f SkColor4f::FromColor(SkColor c) {
     return c4;
 }
 
+SkColor4f SkColor4f::Pin(float a, float r, float g, float b) {
+    SkColor4f c4;
+    Sk4f::Min(Sk4f::Max(Sk4f(a, r, g, b), Sk4f(0)), Sk4f(1)).store(c4.vec());
+    return c4;
+}
+
 SkPM4f SkColor4f::premul() const {
     auto src = Sk4f::Load(this->pin().vec());
     float srcAlpha = src.kth<0>();  // need the pinned version of our alpha

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);
+        }
+    }
+}