C++ SkRandom类代码示例

 HTDrawable(SkRandom& rand) {
     fR = SkRect::MakeXYWH(rand.nextRangeF(0, 640), rand.nextRangeF(0, 480),
                           rand.nextRangeF(20, 200), rand.nextRangeF(20, 200));
     fColor = rand_opaque_color(rand.nextU());
     fInterp = nullptr;
     fTime = 0;
 }

    virtual void onDraw(SkCanvas* canvas) {
        SkPaint paint;
        this->setupPaint(&paint);

        paint.setAntiAlias(true);

        SkRandom rand;
        for (int i = 0; i < SkBENCHLOOP(3); i++) {
            SkRect r = SkRect::MakeWH(rand.nextUScalar1() * 400,
                                      rand.nextUScalar1() * 400);
            r.offset(fRadius, fRadius);

            if (fRadius > 0) {
                SkMorphologyImageFilter* mf = NULL;
                switch (fStyle) {
                case kDilate_MT:
                    mf = new SkDilateImageFilter(SkScalarFloorToInt(fRadius),
                                                 SkScalarFloorToInt(fRadius));
                    break;
                case kErode_MT:
                    mf = new SkErodeImageFilter(SkScalarFloorToInt(fRadius),
                                                SkScalarFloorToInt(fRadius));
                    break;
                }
                paint.setImageFilter(mf)->unref();
            }
            canvas->drawOval(r, paint);
        }
    }

static SkIRect rand_rect(SkRandom& rand, int n) {
    int x = rand.nextS() % n;
    int y = rand.nextS() % n;
    int w = rand.nextU() % n;
    int h = rand.nextU() % n;
    return SkIRect::MakeXYWH(x, y, w, h);
}

DEF_TEST(SkFloatToHalf_finite_ftz, r) {
#if 0
    for (uint64_t bits = 0; bits <= 0xffffffff; bits++) {
#else
    SkRandom rand;
    for (int i = 0; i < 1000000; i++) {
        uint32_t bits = rand.nextU();
#endif
        float f;
        memcpy(&f, &bits, 4);

        uint16_t expected = SkFloatToHalf(f);
        if (!is_finite(expected)) {
            // _finite_ftz() only works for values that can be represented as a finite half float.
            continue;
        }

        uint16_t alternate = expected;
        if (is_denorm(expected)) {
            // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit.
            alternate = signbit(f) ? 0x8000 : 0x0000;
        }

        uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0];
        // _finite_ftz() may truncate instead of rounding, so it may be one too small.
        REPORTER_ASSERT(r, actual == expected  || actual == expected  - 1 ||
                           actual == alternate || actual == alternate - 1);
    }
}

 ComputeChecksumBench(void* param, ChecksumType type) : INHERITED(param), fType(type) {
     SkRandom rand;
     for (int i = 0; i < U32COUNT; ++i) {
         fData[i] = rand.nextU();
     }
     fIsRendering = false;
 }

// Asserts that asset == expected and is peekable.
static void stream_peek_test(skiatest::Reporter* rep,
                             SkStreamAsset* asset,
                             const SkData* expected) {
    if (asset->getLength() != expected->size()) {
        ERRORF(rep, "Unexpected length.");
        return;
    }
    SkRandom rand;
    uint8_t buffer[4096];
    const uint8_t* expect = expected->bytes();
    for (size_t i = 0; i < asset->getLength(); ++i) {
        uint32_t maxSize =
                SkToU32(SkTMin(sizeof(buffer), asset->getLength() - i));
        size_t size = rand.nextRangeU(1, maxSize);
        SkASSERT(size >= 1);
        SkASSERT(size <= sizeof(buffer));
        SkASSERT(size + i <= asset->getLength());
        if (asset->peek(buffer, size) < size) {
            ERRORF(rep, "Peek Failed!");
            return;
        }
        if (0 != memcmp(buffer, &expect[i], size)) {
            ERRORF(rep, "Peek returned wrong bytes!");
            return;
        }
        uint8_t value;
        REPORTER_ASSERT(rep, 1 == asset->read(&value, 1));
        if (value != expect[i]) {
            ERRORF(rep, "Read Failed!");
            return;
        }
    }
}

    void onDraw(int loops, SkCanvas* canvas) override {
        SkPaint paint;
        this->setupPaint(&paint);

        paint.setAntiAlias(true);

        SkRandom rand;
        for (int i = 0; i < loops; i++) {
            SkRect r = SkRect::MakeWH(rand.nextUScalar1() * 400,
                                      rand.nextUScalar1() * 400);
            r.offset(fRadius, fRadius);

            if (fRadius > 0) {
                sk_sp<SkImageFilter> mf;
                switch (fStyle) {
                case kDilate_MT:
                    mf = SkDilateImageFilter::Make(SkScalarFloorToInt(fRadius),
                                                   SkScalarFloorToInt(fRadius),
                                                   nullptr);
                    break;
                case kErode_MT:
                    mf = SkErodeImageFilter::Make(SkScalarFloorToInt(fRadius),
                                                  SkScalarFloorToInt(fRadius),
                                                  nullptr);
                    break;
                }
                paint.setImageFilter(std::move(mf));
            }
            canvas->drawOval(r, paint);
        }
    }

static void test_buffer(skiatest::Reporter* reporter) {
    SkRandom rand;
    SkAutoMalloc am(MAX_SIZE * 2);
    char* storage = (char*)am.get();
    char* storage2 = storage + MAX_SIZE;

    random_fill(rand, storage, MAX_SIZE);

    for (int sizeTimes = 0; sizeTimes < 100; sizeTimes++) {
        int size = rand.nextU() % MAX_SIZE;
        if (size == 0) {
            size = MAX_SIZE;
        }
        for (int times = 0; times < 100; times++) {
            int bufferSize = 1 + (rand.nextU() & 0xFFFF);
            SkMemoryStream mstream(storage, size);
            SkBufferStream bstream(&mstream, bufferSize);

            int bytesRead = 0;
            while (bytesRead < size) {
                int s = 17 + (rand.nextU() & 0xFFFF);
                int ss = bstream.read(storage2, s);
                REPORTER_ASSERT(reporter, ss > 0 && ss <= s);
                REPORTER_ASSERT(reporter, bytesRead + ss <= size);
                REPORTER_ASSERT(reporter,
                                memcmp(storage + bytesRead, storage2, ss) == 0);
                bytesRead += ss;
            }
            REPORTER_ASSERT(reporter, bytesRead == size);
        }
    }
}

static sk_sp<SkImage> make_atlas(int atlasSize, int cellSize) {
    SkImageInfo info = SkImageInfo::MakeN32Premul(atlasSize, atlasSize);
    auto surface(SkSurface::MakeRaster(info));
    SkCanvas* canvas = surface->getCanvas();

    SkPaint paint;
    SkRandom rand;

    const SkScalar half = cellSize * SK_ScalarHalf;
    const char* s = "[email protected]#$%^&*=+<>?abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    SkFont font(nullptr, 28);

    int i = 0;
    for (int y = 0; y < atlasSize; y += cellSize) {
        for (int x = 0; x < atlasSize; x += cellSize) {
            paint.setColor(rand.nextU());
            paint.setAlpha(0xFF);
            int index = i % strlen(s);
            SkTextUtils::Draw(canvas, &s[index], 1, SkTextEncoding::kUTF8,
                              x + half, y + half + half/2, font, paint,
                              SkTextUtils::kCenter_Align);
            i += 1;
        }
    }
    return surface->makeImageSnapshot();
}

static void test_peephole(skiatest::Reporter* reporter) {
    SkRandom rand;

    for (int j = 0; j < 100; j++) {
        SkRandom rand2(rand.getSeed()); // remember the seed

        SkPicture picture;
        SkCanvas* canvas = picture.beginRecording(100, 100);

        for (int i = 0; i < 1000; ++i) {
            rand_op(canvas, rand);
        }
        picture.endRecording();
    }

    {
        SkPicture picture;
        SkCanvas* canvas = picture.beginRecording(100, 100);
        SkRect rect = SkRect::MakeWH(50, 50);

        for (int i = 0; i < 100; ++i) {
            canvas->save();
        }
        while (canvas->getSaveCount() > 1) {
            canvas->clipRect(rect);
            canvas->restore();
        }
        picture.endRecording();
    }
}

    VertBench() {
        const SkScalar dx = SkIntToScalar(W) / COL;
        const SkScalar dy = SkIntToScalar(H) / COL;

        SkPoint* pts = fPts;
        uint16_t* idx = fIdx;

        SkScalar yy = 0;
        for (int y = 0; y <= ROW; y++) {
            SkScalar xx = 0;
            for (int x = 0; x <= COL; ++x) {
                pts->set(xx, yy);
                pts += 1;
                xx += dx;

                if (x < COL && y < ROW) {
                    load_2_tris(idx, x, y, COL + 1);
                    for (int i = 0; i < 6; i++) {
                        SkASSERT(idx[i] < PTS);
                    }
                    idx += 6;
                }
            }
            yy += dy;
        }
        SkASSERT(PTS == pts - fPts);
        SkASSERT(IDX == idx - fIdx);

        SkRandom rand;
        for (int i = 0; i < PTS; ++i) {
            fColors[i] = rand.nextU() | (0xFF << 24);
        }

        fName.set("verts");
    }

static void call_draw(SkCanvas* canvas)
    {
    SkPaint paint;
    uint16_t text[32];
    SkRandom rand;

    paint.setAntiAlias(true);
    paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
    for (int j = 0; j < SK_ARRAY_COUNT(text); j++)
        text[j] = (uint16_t)((rand.nextU() & 0xFF) + 32);

    SkScalar x = SkIntToScalar(10);
    SkScalar y = SkIntToScalar(20);

    canvas->drawColor(SK_ColorWHITE);
    for (int i = 9; i < 36; i++)
        {
        SkPaint::FontMetrics m;

        paint.setTextSize(SkIntToScalar(i));
        paint.getFontMetrics(&m);
        canvas->drawText(text, sizeof(text), x, y, paint);
        y += m.fDescent - m.fAscent;
        }
    }

    void onDraw(const int loops, SkCanvas*) override {
        SkRandom r;
        enum {
            kMaxObjects = 4 * (1 << 10),
        };
        A* objects[kMaxObjects];

        // We delete if a random [-1, 1] fixed pt is < the thresh. Otherwise,
        // we allocate. We start allocate-biased and ping-pong to delete-biased
        SkFixed delThresh = -SK_FixedHalf;
        const int kSwitchThreshPeriod = loops / (2 * kMaxObjects);
        int s = 0;

        int count = 0;
        for (int i = 0; i < loops; i++, ++s) {
            if (kSwitchThreshPeriod == s) {
                delThresh = -delThresh;
                s = 0;
            }
            SkFixed del = r.nextSFixed1();
            if (count &&
                (kMaxObjects == count || del < delThresh)) {
                delete objects[count-1];
                --count;
            } else {
                objects[count] = new A;
                ++count;
            }
        }
        for (int i = 0; i < count; ++i) {
            delete objects[i];
        }
    }

const GrFragmentProcessor* SkModeColorFilter::asFragmentProcessor(GrContext*) const {
    if (SkXfermode::kDst_Mode == fMode) {
        return nullptr;
    }

    SkAutoTUnref<const GrFragmentProcessor> constFP(
        GrConstColorProcessor::Create(SkColorToPremulGrColor(fColor),
                                        GrConstColorProcessor::kIgnore_InputMode));
    const GrFragmentProcessor* fp =
        GrXfermodeFragmentProcessor::CreateFromSrcProcessor(constFP, fMode);
    if (!fp) {
        return nullptr;
    }
#ifdef SK_DEBUG
    // With a solid color input this should always be able to compute the blended color
    // (at least for coeff modes)
    if (fMode <= SkXfermode::kLastCoeffMode) {
        static SkRandom gRand;
        GrInvariantOutput io(GrPremulColor(gRand.nextU()), kRGBA_GrColorComponentFlags,
                                false);
        fp->computeInvariantOutput(&io);
        SkASSERT(io.validFlags() == kRGBA_GrColorComponentFlags);
    }
#endif
    return fp;
}

    void onDraw(SkCanvas* canvas) override {
        SkPath path;
        SkRandom rand;

        int scale = 300;
        for (int i = 0; i < 4; ++i) {
            // get the random values deterministically
            SkScalar randoms[12];
            for (int index = 0; index < (int) SK_ARRAY_COUNT(randoms); ++index) {
                randoms[index] = rand.nextUScalar1();
            }
            path.lineTo(randoms[0] * scale, randoms[1] * scale);
            path.quadTo(randoms[2] * scale, randoms[3] * scale,
                        randoms[4] * scale, randoms[5] * scale);
            path.cubicTo(randoms[6] * scale, randoms[7] * scale,
                         randoms[8] * scale, randoms[9] * scale,
                         randoms[10] * scale, randoms[11] * scale);
        }

        path.setFillType(SkPath::kEvenOdd_FillType);
        path.offset(SkIntToScalar(20), SkIntToScalar(20));

        test_hittest(canvas, path);

        canvas->translate(SkIntToScalar(scale), 0);
        path.setFillType(SkPath::kWinding_FillType);

        test_hittest(canvas, path);
    }