Convert gradient params test helper to a struct

Much less copy-pasted code, fewer implementation details leaking out,
and going to be easier to extend for 4f and color space testing.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2900

Change-Id: Icc468c606aa35fbe82c64bcc398e7e348e0faa20
Reviewed-on: https://skia-review.googlesource.com/2900
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>

6 files changed, 51 insertions, 73 deletions

diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 17302d9d4f..bedc6e8868 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -1723,28 +1723,25 @@ void GrGradientEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const
     }
 }
 
-int GrGradientEffect::RandomGradientParams(SkRandom* random,
-                                           SkColor colors[],
-                                           SkScalar** stops,
-                                           SkShader::TileMode* tm) {
-    int outColors = random->nextRangeU(1, kMaxRandomGradientColors);
+GrGradientEffect::RandomGradientParams::RandomGradientParams(SkRandom* random) {
+    fColorCount = random->nextRangeU(1, kMaxRandomGradientColors);
 
     // if one color, omit stops, otherwise randomly decide whether or not to
-    if (outColors == 1 || (outColors >= 2 && random->nextBool())) {
-        *stops = nullptr;
+    if (fColorCount == 1 || (fColorCount >= 2 && random->nextBool())) {
+        fStops = nullptr;
+    } else {
+        fStops = fStopStorage;
     }
 
     SkScalar stop = 0.f;
-    for (int i = 0; i < outColors; ++i) {
-        colors[i] = random->nextU();
-        if (*stops) {
-            (*stops)[i] = stop;
-            stop = i < outColors - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f;
+    for (int i = 0; i < fColorCount; ++i) {
+        fColors[i] = random->nextU();
+        if (fStops) {
+            fStops[i] = stop;
+            stop = i < fColorCount - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f;
         }
     }
-    *tm = static_cast<SkShader::TileMode>(random->nextULessThan(SkShader::kTileModeCount));
-
-    return outColors;
+    fTileMode = static_cast<SkShader::TileMode>(random->nextULessThan(SkShader::kTileModeCount));
 }
 
 #endif
diff --git a/src/effects/gradients/SkGradientShaderPriv.h b/src/effects/gradients/SkGradientShaderPriv.h
index 61a44184ff..bbc94907d8 100644
--- a/src/effects/gradients/SkGradientShaderPriv.h
+++ b/src/effects/gradients/SkGradientShaderPriv.h
@@ -408,10 +408,15 @@ protected:
         be passed to the gradient factory rather than the array.
     */
     static const int kMaxRandomGradientColors = 4;
-    static int RandomGradientParams(SkRandom* r,
-                                    SkColor colors[kMaxRandomGradientColors],
-                                    SkScalar** stops,
-                                    SkShader::TileMode* tm);
+    struct RandomGradientParams {
+        RandomGradientParams(SkRandom* r);
+
+        SkColor fColors[kMaxRandomGradientColors];
+        SkScalar fStopStorage[kMaxRandomGradientColors];
+        SkShader::TileMode fTileMode;
+        int fColorCount;
+        SkScalar* fStops;
+    };
 
     bool onIsEqual(const GrFragmentProcessor&) const override;
 
diff --git a/src/effects/gradients/SkLinearGradient.cpp b/src/effects/gradients/SkLinearGradient.cpp
index a249ae4ac8..2fcaae1ca9 100644
--- a/src/effects/gradients/SkLinearGradient.cpp
+++ b/src/effects/gradients/SkLinearGradient.cpp
@@ -414,12 +414,9 @@ sk_sp<GrFragmentProcessor> GrLinearGradient::TestCreate(GrProcessorTestData* d)
     SkPoint points[] = {{d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()},
                         {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()}};
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
-    auto shader = SkGradientShader::MakeLinear(points, colors, stops, colorCount, tm);
+    RandomGradientParams params(d->fRandom);
+    auto shader = SkGradientShader::MakeLinear(points, params.fColors, params.fStops,
+                                               params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
diff --git a/src/effects/gradients/SkRadialGradient.cpp b/src/effects/gradients/SkRadialGradient.cpp
index 18ef376862..f13deb1cdb 100644
--- a/src/effects/gradients/SkRadialGradient.cpp
+++ b/src/effects/gradients/SkRadialGradient.cpp
@@ -308,12 +308,9 @@ sk_sp<GrFragmentProcessor> GrRadialGradient::TestCreate(GrProcessorTestData* d)
     SkPoint center = {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()};
     SkScalar radius = d->fRandom->nextUScalar1();
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
-    auto shader = SkGradientShader::MakeRadial(center, radius, colors, stops, colorCount, tm);
+    RandomGradientParams params(d->fRandom);
+    auto shader = SkGradientShader::MakeRadial(center, radius, params.fColors, params.fStops,
+                                               params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
diff --git a/src/effects/gradients/SkSweepGradient.cpp b/src/effects/gradients/SkSweepGradient.cpp
index d1fe269b9c..f4ef8ab41f 100644
--- a/src/effects/gradients/SkSweepGradient.cpp
+++ b/src/effects/gradients/SkSweepGradient.cpp
@@ -190,13 +190,9 @@ GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrSweepGradient);
 sk_sp<GrFragmentProcessor> GrSweepGradient::TestCreate(GrProcessorTestData* d) {
     SkPoint center = {d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1()};
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tmIgnored;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tmIgnored);
-    sk_sp<SkShader> shader(SkGradientShader::MakeSweep(center.fX, center.fY,  colors, stops,
-                                                       colorCount));
+    RandomGradientParams params(d->fRandom);
+    sk_sp<SkShader> shader(SkGradientShader::MakeSweep(center.fX, center.fY,  params.fColors,
+                                                       params.fStops, params.fColorCount));
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
diff --git a/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp b/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
index a8df3b50c3..00d8fac73f 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient_gpu.cpp
@@ -199,13 +199,10 @@ sk_sp<GrFragmentProcessor> Edge2PtConicalEffect::TestCreate(GrProcessorTestData*
     SkScalar diffLen = diff.length();
     radius2 = radius1 + diffLen;
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
+    RandomGradientParams params(d->fRandom);
     auto shader = SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2,
-                                                        colors, stops, colorCount, tm);
+                                                        params.fColors, params.fStops,
+                                                        params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
@@ -470,18 +467,16 @@ sk_sp<GrFragmentProcessor> FocalOutside2PtConicalEffect::TestCreate(GrProcessorT
         center2.set(d->fRandom->nextUScalar1(), d->fRandom->nextUScalar1());
         // Need to make sure the centers are not the same or else focal point will be inside
     } while (center1 == center2);
-        SkPoint diff = center2 - center1;
-        SkScalar diffLen = diff.length();
-        // Below makes sure that the focal point is not contained within circle two
-        radius2 = d->fRandom->nextRangeF(0.f, diffLen);
-
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
+
+    SkPoint diff = center2 - center1;
+    SkScalar diffLen = diff.length();
+    // Below makes sure that the focal point is not contained within circle two
+    radius2 = d->fRandom->nextRangeF(0.f, diffLen);
+
+    RandomGradientParams params(d->fRandom);
     auto shader = SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2,
-                                                        colors, stops, colorCount, tm);
+                                                        params.fColors, params.fStops,
+                                                        params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
@@ -680,13 +675,10 @@ sk_sp<GrFragmentProcessor> FocalInside2PtConicalEffect::TestCreate(GrProcessorTe
         // If the circles are identical the factory will give us an empty shader.
     } while (radius1 == radius2 && center1 == center2);
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
+    RandomGradientParams params(d->fRandom);
     auto shader = SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2,
-                                                        colors, stops, colorCount, tm);
+                                                        params.fColors, params.fStops,
+                                                        params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
@@ -927,13 +919,10 @@ sk_sp<GrFragmentProcessor> CircleInside2PtConicalEffect::TestCreate(GrProcessorT
         // If the circles are identical the factory will give us an empty shader.
     } while (radius1 == radius2 && center1 == center2);
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
+    RandomGradientParams params(d->fRandom);
     auto shader = SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2,
-                                                        colors, stops, colorCount, tm);
+                                                        params.fColors, params.fStops,
+                                                        params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(
@@ -1161,13 +1150,10 @@ sk_sp<GrFragmentProcessor> CircleOutside2PtConicalEffect::TestCreate(GrProcessor
     // and have radius2 >= radius to match sorting on cpu side
     radius2 = radius1 + d->fRandom->nextRangeF(0.f, diffLen);
 
-    SkColor colors[kMaxRandomGradientColors];
-    SkScalar stopsArray[kMaxRandomGradientColors];
-    SkScalar* stops = stopsArray;
-    SkShader::TileMode tm;
-    int colorCount = RandomGradientParams(d->fRandom, colors, &stops, &tm);
+    RandomGradientParams params(d->fRandom);
     auto shader = SkGradientShader::MakeTwoPointConical(center1, radius1, center2, radius2,
-                                                        colors, stops, colorCount, tm);
+                                                        params.fColors, params.fStops,
+                                                        params.fColorCount, params.fTileMode);
     SkMatrix viewMatrix = GrTest::TestMatrix(d->fRandom);
     auto dstColorSpace = GrTest::TestColorSpace(d->fRandom);
     sk_sp<GrFragmentProcessor> fp = shader->asFragmentProcessor(SkShader::AsFPArgs(