C++ SkImageInfo::computeByteSize方法代码示例

sk_sp<SkImage> SkImageMakeRasterCopyAndAssignColorSpace(const SkImage* src,
                                                        SkColorSpace* colorSpace) {
    // Read the pixels out of the source image, with no conversion
    SkImageInfo info = as_IB(src)->onImageInfo();
    if (kUnknown_SkColorType == info.colorType()) {
        SkDEBUGFAIL("Unexpected color type");
        return nullptr;
    }

    size_t rowBytes = info.minRowBytes();
    size_t size = info.computeByteSize(rowBytes);
    if (SkImageInfo::ByteSizeOverflowed(size)) {
        return nullptr;
    }
    auto data = SkData::MakeUninitialized(size);
    if (!data) {
        return nullptr;
    }

    SkPixmap pm(info, data->writable_data(), rowBytes);
    if (!src->readPixels(pm, 0, 0, SkImage::kDisallow_CachingHint)) {
        return nullptr;
    }

    // Wrap them in a new image with a different color space
    return SkImage::MakeRasterData(info.makeColorSpace(sk_ref_sp(colorSpace)), data, rowBytes);
}

static void check_fill(skiatest::Reporter* r,
                       const SkImageInfo& imageInfo,
                       uint32_t startRow,
                       uint32_t endRow,
                       size_t rowBytes,
                       uint32_t offset,
                       uint32_t colorOrIndex) {

    // Calculate the total size of the image in bytes.  Use the smallest possible size.
    // The offset value tells us to adjust the pointer from the memory we allocate in order
    // to test on different memory alignments.  If offset is nonzero, we need to increase the
    // size of the memory we allocate in order to make sure that we have enough.  We are
    // still allocating the smallest possible size.
    const size_t totalBytes = imageInfo.computeByteSize(rowBytes) + offset;

    // Create fake image data where every byte has a value of 0
    std::unique_ptr<uint8_t[]> storage(new uint8_t[totalBytes]);
    memset(storage.get(), 0, totalBytes);
    // Adjust the pointer in order to test on different memory alignments
    uint8_t* imageData = storage.get() + offset;
    uint8_t* imageStart = imageData + rowBytes * startRow;
    const SkImageInfo fillInfo = imageInfo.makeWH(imageInfo.width(), endRow - startRow + 1);
    SkSampler::Fill(fillInfo, imageStart, rowBytes, colorOrIndex, SkCodec::kNo_ZeroInitialized);

    // Ensure that the pixels are filled properly
    // The bots should catch any memory corruption
    uint8_t* indexPtr = imageData + startRow * rowBytes;
    uint8_t* grayPtr = indexPtr;
    uint32_t* colorPtr = (uint32_t*) indexPtr;
    uint16_t* color565Ptr = (uint16_t*) indexPtr;
    for (uint32_t y = startRow; y <= endRow; y++) {
        for (int32_t x = 0; x < imageInfo.width(); x++) {
            switch (imageInfo.colorType()) {
                case kN32_SkColorType:
                    REPORTER_ASSERT(r, kFillColor == colorPtr[x]);
                    break;
                case kGray_8_SkColorType:
                    REPORTER_ASSERT(r, kFillGray == grayPtr[x]);
                    break;
                case kRGB_565_SkColorType:
                    REPORTER_ASSERT(r, kFill565 == color565Ptr[x]);
                    break;
                default:
                    REPORTER_ASSERT(r, false);
                    break;
            }
        }
        indexPtr += rowBytes;
        colorPtr = (uint32_t*) indexPtr;
    }
}

sk_sp<SkImage> SkImage::makeRasterImage() const {
    SkPixmap pm;
    if (this->peekPixels(&pm)) {
        return sk_ref_sp(const_cast<SkImage*>(this));
    }

    const SkImageInfo info = as_IB(this)->onImageInfo();
    const size_t rowBytes = info.minRowBytes();
    size_t size = info.computeByteSize(rowBytes);
    if (SkImageInfo::ByteSizeOverflowed(size)) {
        return nullptr;
    }

    sk_sp<SkData> data = SkData::MakeUninitialized(size);
    pm = { info.makeColorSpace(nullptr), data->writable_data(), info.minRowBytes() };
    if (!this->readPixels(pm, 0, 0)) {
        return nullptr;
    }

    return SkImage::MakeRasterData(info, std::move(data), rowBytes);
}

static void test_newraster(skiatest::Reporter* reporter) {
    SkImageInfo info = SkImageInfo::MakeN32Premul(10, 10);
    const size_t minRowBytes = info.minRowBytes();
    const size_t size = info.computeByteSize(minRowBytes);
    SkAutoTMalloc<SkPMColor> storage(size);
    SkPMColor* baseAddr = storage.get();
    sk_bzero(baseAddr, size);

    std::unique_ptr<SkCanvas> canvas = SkCanvas::MakeRasterDirect(info, baseAddr, minRowBytes);
    REPORTER_ASSERT(reporter, canvas);

    SkPixmap pmap;
    const SkPMColor* addr = canvas->peekPixels(&pmap) ? pmap.addr32() : nullptr;
    REPORTER_ASSERT(reporter, addr);
    REPORTER_ASSERT(reporter, info == pmap.info());
    REPORTER_ASSERT(reporter, minRowBytes == pmap.rowBytes());
    for (int y = 0; y < info.height(); ++y) {
        for (int x = 0; x < info.width(); ++x) {
            REPORTER_ASSERT(reporter, 0 == addr[x]);
        }
        addr = (const SkPMColor*)((const char*)addr + pmap.rowBytes());
    }

    // now try a deliberately bad info
    info = info.makeWH(-1, info.height());
    REPORTER_ASSERT(reporter, nullptr == SkCanvas::MakeRasterDirect(info, baseAddr, minRowBytes));

    // too big
    info = info.makeWH(1 << 30, 1 << 30);
    REPORTER_ASSERT(reporter, nullptr == SkCanvas::MakeRasterDirect(info, baseAddr, minRowBytes));

    // not a valid pixel type
    info = SkImageInfo::Make(10, 10, kUnknown_SkColorType, info.alphaType());
    REPORTER_ASSERT(reporter, nullptr == SkCanvas::MakeRasterDirect(info, baseAddr, minRowBytes));

    // We should succeed with a zero-sized valid info
    info = SkImageInfo::MakeN32Premul(0, 0);
    canvas = SkCanvas::MakeRasterDirect(info, baseAddr, minRowBytes);
    REPORTER_ASSERT(reporter, canvas);
}

void SkSampler::Fill(const SkImageInfo& info, void* dst, size_t rowBytes,
        uint64_t colorOrIndex, SkCodec::ZeroInitialized zeroInit) {
    SkASSERT(dst != nullptr);

    // Calculate bytes to fill.
    const size_t bytesToFill = info.computeByteSize(rowBytes);
    const int width = info.width();
    const int numRows = info.height();

    // Use the proper memset routine to fill the remaining bytes
    switch (info.colorType()) {
        case kRGBA_8888_SkColorType:
        case kBGRA_8888_SkColorType: {
            // If memory is zero initialized, we may not need to fill
            uint32_t color = (uint32_t) colorOrIndex;
            if (SkCodec::kYes_ZeroInitialized == zeroInit && 0 == color) {
                return;
            }

            uint32_t* dstRow = (uint32_t*) dst;
            for (int row = 0; row < numRows; row++) {
                sk_memset32((uint32_t*) dstRow, color, width);
                dstRow = SkTAddOffset<uint32_t>(dstRow, rowBytes);
            }
            break;
        }
        case kRGB_565_SkColorType: {
            // If the destination is k565, the caller passes in a 16-bit color.
            // We will not assert that the high bits of colorOrIndex must be zeroed.
            // This allows us to take advantage of the fact that the low 16 bits of an
            // SKPMColor may be a valid a 565 color.  For example, the low 16
            // bits of SK_ColorBLACK are identical to the 565 representation
            // for black.

            // If memory is zero initialized, we may not need to fill
            uint16_t color = (uint16_t) colorOrIndex;
            if (SkCodec::kYes_ZeroInitialized == zeroInit && 0 == color) {
                return;
            }

            uint16_t* dstRow = (uint16_t*) dst;
            for (int row = 0; row < numRows; row++) {
                sk_memset16((uint16_t*) dstRow, color, width);
                dstRow = SkTAddOffset<uint16_t>(dstRow, rowBytes);
            }
            break;
        }
        case kGray_8_SkColorType:
            // If the destination is kGray, the caller passes in an 8-bit color.
            // We will not assert that the high bits of colorOrIndex must be zeroed.
            // This allows us to take advantage of the fact that the low 8 bits of an
            // SKPMColor may be a valid a grayscale color.  For example, the low 8
            // bits of SK_ColorBLACK are identical to the grayscale representation
            // for black.

            // If memory is zero initialized, we may not need to fill
            if (SkCodec::kYes_ZeroInitialized == zeroInit && 0 == (uint8_t) colorOrIndex) {
                return;
            }

            memset(dst, (uint8_t) colorOrIndex, bytesToFill);
            break;
        case kRGBA_F16_SkColorType: {
            uint64_t color = colorOrIndex;
            if (SkCodec::kYes_ZeroInitialized == zeroInit && 0 == color) {
                return;
            }

            uint64_t* dstRow = (uint64_t*) dst;
            for (int row = 0; row < numRows; row++) {
                sk_memset64((uint64_t*) dstRow, color, width);
                dstRow = SkTAddOffset<uint64_t>(dstRow, rowBytes);
            }
            break;
        }
        default:
            SkCodecPrintf("Error: Unsupported dst color type for fill().  Doing nothing.\n");
            SkASSERT(false);
            break;
    }
}