C++ SkRandom::nextU方法代码示例

 SkIRect randrect(SkRandom& rand) {
     int x = rand.nextU() % W;
     int y = rand.nextU() % H;
     int w = rand.nextU() % W;
     int h = rand.nextU() % H;
     return SkIRect::MakeXYWH(x, y, w >> 1, h >> 1);
 }

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 void rand_irect(SkIRect* r, int N, SkRandom& rand) {
    r->setXYWH(0, 0, rand.nextU() % N, rand.nextU() % N);
    int dx = rand.nextU() % (2*N);
    int dy = rand.nextU() % (2*N);
    // use int dx,dy to make the subtract be signed
    r->offset(N - dx, N - dy);
}

DEF_TEST(Checksum, r) {
    // Algorithms to test.  They're currently all uint32_t(const uint32_t*, size_t).
    typedef uint32_t(*algorithmProc)(const uint32_t*, size_t);
    const algorithmProc kAlgorithms[] = { &SkChecksum::Compute, &murmur_noseed };

    // Put 128 random bytes into two identical buffers.  Any multiple of 4 will do.
    const size_t kBytes = SkAlign4(128);
    SkRandom rand;
    uint32_t data[kBytes/4], tweaked[kBytes/4];
    for (size_t i = 0; i < SK_ARRAY_COUNT(tweaked); ++i) {
        data[i] = tweaked[i] = rand.nextU();
    }

    // Test each algorithm.
    for (size_t i = 0; i < SK_ARRAY_COUNT(kAlgorithms); ++i) {
        const algorithmProc algorithm = kAlgorithms[i];

        // Hash of nullptr is always 0.
        ASSERT(algorithm(nullptr, 0) == 0);

        const uint32_t hash = algorithm(data, kBytes);
        // Should be deterministic.
        ASSERT(hash == algorithm(data, kBytes));

        // Changing any single element should change the hash.
        for (size_t j = 0; j < SK_ARRAY_COUNT(tweaked); ++j) {
            const uint32_t saved = tweaked[j];
            tweaked[j] = rand.nextU();
            const uint32_t tweakedHash = algorithm(tweaked, kBytes);
            ASSERT(tweakedHash != hash);
            ASSERT(tweakedHash == algorithm(tweaked, kBytes));
            tweaked[j] = saved;
        }
    }
}

static void show_stroke(SkCanvas* canvas, bool doAA, SkScalar strokeWidth, int n) {
    SkRandom rand;
    SkPaint paint;
    paint.setAntiAlias(doAA);
    paint.setStyle(SkPaint::kStroke_Style);
    paint.setStrokeWidth(strokeWidth);
    
    for (int i = 0; i < n; ++i) {
        SkRect r;
        SkPath p;
        
        r.setXYWH(rand.nextSScalar1() * W, rand.nextSScalar1() * H,
                  rand.nextUScalar1() * W, rand.nextUScalar1() * H);
        paint.setColor(rand.nextU());
        canvas->drawRect(r, paint);
        
        r.setXYWH(rand.nextSScalar1() * W, rand.nextSScalar1() * H,
                  rand.nextUScalar1() * W, rand.nextUScalar1() * H);
        paint.setColor(rand.nextU());
        p.addOval(r);
        canvas->drawPath(p, paint);

        const SkScalar minx = -SkIntToScalar(W)/4;
        const SkScalar maxx = 5*SkIntToScalar(W)/4;
        const SkScalar miny = -SkIntToScalar(H)/4;
        const SkScalar maxy = 5*SkIntToScalar(H)/4;
        paint.setColor(rand.nextU());
        canvas->drawLine(randRange(rand, minx, maxx), randRange(rand, miny, maxy),
                         randRange(rand, minx, maxx), randRange(rand, miny, maxy),
                         paint);
    }
}

DEF_TEST(Paint_cmap, reporter) {
    // need to implement charsToGlyphs on other backends (e.g. linux, win)
    // before we can run this tests everywhere
    return;

    static const int NGLYPHS = 64;

    SkUnichar src[NGLYPHS];
    SkUnichar dst[NGLYPHS]; // used for utf8, utf16, utf32 storage

    static const struct {
        size_t (*fSeedTextProc)(const SkUnichar[], void* dst, int count);
        SkPaint::TextEncoding   fEncoding;
    } gRec[] = {
        { uni_to_utf8,  SkPaint::kUTF8_TextEncoding },
        { uni_to_utf16, SkPaint::kUTF16_TextEncoding },
        { uni_to_utf32, SkPaint::kUTF32_TextEncoding },
    };

    SkRandom rand;
    SkPaint paint;
    paint.setTypeface(SkTypeface::RefDefault())->unref();
    SkTypeface* face = paint.getTypeface();

    for (int i = 0; i < 1000; ++i) {
        // generate some random text
        for (int j = 0; j < NGLYPHS; ++j) {
            src[j] = ' ' + j;
        }
        // inject some random chars, to sometimes abort early
        src[rand.nextU() & 63] = rand.nextU() & 0xFFF;

        for (size_t k = 0; k < SK_ARRAY_COUNT(gRec); ++k) {
            paint.setTextEncoding(gRec[k].fEncoding);

            size_t len = gRec[k].fSeedTextProc(src, dst, NGLYPHS);

            uint16_t    glyphs0[NGLYPHS], glyphs1[NGLYPHS];

            bool contains = paint.containsText(dst, len);
            int nglyphs = paint.textToGlyphs(dst, len, glyphs0);
            int first = face->charsToGlyphs(dst, paint2encoding(paint), glyphs1, NGLYPHS);
            int index = find_first_zero(glyphs1, NGLYPHS);

            REPORTER_ASSERT(reporter, NGLYPHS == nglyphs);
            REPORTER_ASSERT(reporter, index == first);
            REPORTER_ASSERT(reporter, 0 == memcmp(glyphs0, glyphs1, NGLYPHS * sizeof(uint16_t)));
            if (contains) {
                REPORTER_ASSERT(reporter, NGLYPHS == first);
            } else {
                REPORTER_ASSERT(reporter, NGLYPHS > first);
            }
        }
    }
}

static void test_pack8(skiatest::Reporter* reporter) {
    static const struct {
        const uint8_t* fSrc;
        int             fCount;
    } gTests[] = {
        { gTest80, SK_ARRAY_COUNT(gTest80) },
        { gTest81, SK_ARRAY_COUNT(gTest81) },
        { gTest82, SK_ARRAY_COUNT(gTest82) },
        { gTest83, SK_ARRAY_COUNT(gTest83) },
        { gTest84, SK_ARRAY_COUNT(gTest84) }
    };

    for (size_t i = 4; i < SK_ARRAY_COUNT(gTests); i++) {
        uint8_t dst[100];
        size_t maxSize = SkPackBits::ComputeMaxSize8(gTests[i].fCount);
        size_t dstSize = SkPackBits::Pack8(gTests[i].fSrc,
                                           gTests[i].fCount, dst);
        REPORTER_ASSERT(reporter, dstSize <= maxSize);
        uint8_t src[100];
        int srcCount = SkPackBits::Unpack8(dst, dstSize, src);
        bool match = gTests[i].fCount == srcCount &&
                    memcmp(gTests[i].fSrc, src,
                           gTests[i].fCount * sizeof(uint8_t)) == 0;
        REPORTER_ASSERT(reporter, match);
    }

    for (size_t size = 1; size <= 512; size += 1) {
        for (int n = 100; n; n--) {
            uint8_t src[600], src2[600];
            uint8_t dst[600];
            rand_fill(src, size);

            size_t dstSize = SkPackBits::Pack8(src, size, dst);
            size_t maxSize = SkPackBits::ComputeMaxSize8(size);
            REPORTER_ASSERT(reporter, maxSize >= dstSize);

            size_t srcCount = SkPackBits::Unpack8(dst, dstSize, src2);
            REPORTER_ASSERT(reporter, size == srcCount);
            bool match = memcmp(src, src2, size * sizeof(uint8_t)) == 0;
            REPORTER_ASSERT(reporter, match);

            for (int j = 0; j < 100; j++) {
                size_t skip = gRand.nextU() % size;
                size_t write = gRand.nextU() % size;
                if (skip + write > size) {
                    write = size - skip;
                }
                SkPackBits::Unpack8(src, skip, write, dst);
                bool match = memcmp(src, src2 + skip, write) == 0;
                REPORTER_ASSERT(reporter, match);
            }
        }
    }
}

    void onDraw(SkCanvas* canvas) override {
        // Draw a giant AA circle as the background.
        SkISize size = this->getISize();
        SkScalar giantRadius = SkTMin(SkIntToScalar(size.fWidth),
                                      SkIntToScalar(size.fHeight)) / 2.f;
        SkPoint giantCenter = SkPoint::Make(SkIntToScalar(size.fWidth/2),
                                            SkIntToScalar(size.fHeight/2));
        SkPaint giantPaint;
        giantPaint.setAntiAlias(true);
        giantPaint.setColor(0x80808080);
        canvas->drawCircle(giantCenter.fX, giantCenter.fY, giantRadius, giantPaint);

        SkRandom rand;
        canvas->translate(20 * SK_Scalar1, 20 * SK_Scalar1);
        int i;
        for (i = 0; i < fPaints.count(); ++i) {
            canvas->save();
            // position the path, and make it at off-integer coords.
            canvas->translate(SK_Scalar1 * 200 * (i % 5) + SK_Scalar1 / 4,
                              SK_Scalar1 * 200 * (i / 5) + 3 * SK_Scalar1 / 4);
            SkColor color = rand.nextU();
            color |= 0xff000000;
            fPaints[i].setColor(color);

            canvas->drawCircle(SkIntToScalar(40), SkIntToScalar(40),
                               SkIntToScalar(20),
                               fPaints[i]);
            canvas->restore();
        }

        for (int j = 0; j < fMatrices.count(); ++j, ++i) {
            canvas->save();

            canvas->translate(SK_Scalar1 * 200 * (i % 5) + SK_Scalar1 / 4,
                              SK_Scalar1 * 200 * (i / 5) + 3 * SK_Scalar1 / 4);

            canvas->concat(fMatrices[j]);

            SkPaint paint;
            paint.setAntiAlias(true);

            SkColor color = rand.nextU();
            color |= 0xff000000;
            paint.setColor(color);

            canvas->drawCircle(SkIntToScalar(40), SkIntToScalar(40),
                               SkIntToScalar(20),
                               paint);

            canvas->restore();
        }
    }

 void onDraw(const int loops, SkCanvas* canvas) override {
     const char* text = "Hamburgefons";
     size_t len = strlen(text);
     SkISize size = canvas->getDeviceSize();
     SkRandom random;
     for (int i = 0; i < loops; ++i) {
         SkPaint paint;
         paint.setXfermode(fXfermode.get());
         paint.setColor(random.nextU());
         if (fAA) {
             // Draw text to exercise AA code paths.
             paint.setAntiAlias(true);
             paint.setTextSize(random.nextRangeScalar(12, 96));
             SkScalar x = random.nextRangeScalar(0, (SkScalar)size.fWidth),
                      y = random.nextRangeScalar(0, (SkScalar)size.fHeight);
             for (int j = 0; j < 1000; ++j) {
                 canvas->drawText(text, len, x, y, paint);
             }
         } else {
             // Draw rects to exercise non-AA code paths.
             SkScalar w = random.nextRangeScalar(50, 100);
             SkScalar h = random.nextRangeScalar(50, 100);
             SkRect rect = SkRect::MakeXYWH(
                 random.nextUScalar1() * (size.fWidth - w),
                 random.nextUScalar1() * (size.fHeight - h),
                 w,
                 h
             );
             for (int j = 0; j < 1000; ++j) {
                 canvas->drawRect(rect, paint);
             }
         }
     }
 }

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 random_fill(SkRandom& rand, void* buffer, size_t size) {
    char* p = (char*)buffer;
    char* stop = p + size;
    while (p < stop) {
        *p++ = (char)(rand.nextU() >> 8);
    }
}

    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;
        }
    }

 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;
 }

DEF_TEST(ColorFilter, reporter) {
    SkRandom rand;

    for (int mode = 0; mode <= SkXfermode::kLastMode; mode++) {
        SkColor color = rand.nextU();

        // ensure we always get a filter, by avoiding the possibility of a
        // special case that would return NULL (if color's alpha is 0 or 0xFF)
        color = SkColorSetA(color, 0x7F);

        SkColorFilter* cf = SkColorFilter::CreateModeFilter(color,
                                                        (SkXfermode::Mode)mode);

        // allow for no filter if we're in Dst mode (its a no op)
        if (SkXfermode::kDst_Mode == mode && NULL == cf) {
            continue;
        }

        SkAutoUnref aur(cf);
        REPORTER_ASSERT(reporter, cf);

        SkColor c = ~color;
        SkXfermode::Mode m = ILLEGAL_MODE;

        SkColor expectedColor = color;
        SkXfermode::Mode expectedMode = (SkXfermode::Mode)mode;

//        SkDebugf("--- mc [%d %x] ", mode, color);

        REPORTER_ASSERT(reporter, cf->asColorMode(&c, &m));
        // handle special-case folding by the factory
        if (SkXfermode::kClear_Mode == mode) {
            if (c != expectedColor) {
                expectedColor = 0;
            }
            if (m != expectedMode) {
                expectedMode = SkXfermode::kSrc_Mode;
            }
        }

//        SkDebugf("--- got [%d %x] expected [%d %x]\n", m, c, expectedMode, expectedColor);

        REPORTER_ASSERT(reporter, c == expectedColor);
        REPORTER_ASSERT(reporter, m == expectedMode);

        {
            SkColorFilter* cf2 = reincarnate_colorfilter(cf);
            SkAutoUnref aur2(cf2);
            REPORTER_ASSERT(reporter, cf2);

            SkColor c2 = ~color;
            SkXfermode::Mode m2 = ILLEGAL_MODE;
            REPORTER_ASSERT(reporter, cf2->asColorMode(&c2, &m2));
            REPORTER_ASSERT(reporter, c2 == expectedColor);
            REPORTER_ASSERT(reporter, m2 == expectedMode);
        }
    }

    test_composecolorfilter_limit(reporter);
}