C++ Uint8ClampedArray::length方法代码示例

inline void FEGaussianBlur::platformApplyGeneric(Uint8ClampedArray* srcPixelArray, Uint8ClampedArray* tmpPixelArray, unsigned kernelSizeX, unsigned kernelSizeY, IntSize& paintSize)
{
    int stride = 4 * paintSize.width();
    int dxLeft = 0;
    int dxRight = 0;
    int dyLeft = 0;
    int dyRight = 0;
    Uint8ClampedArray* src = srcPixelArray;
    Uint8ClampedArray* dst = tmpPixelArray;

    for (int i = 0; i < 3; ++i) {
        if (kernelSizeX) {
            kernelPosition(i, kernelSizeX, dxLeft, dxRight);
            boxBlur(src, dst, kernelSizeX, dxLeft, dxRight, 4, stride, paintSize.width(), paintSize.height(), isAlphaImage());
            swap(src, dst);
        }

        if (kernelSizeY) {
            kernelPosition(i, kernelSizeY, dyLeft, dyRight);
            boxBlur(src, dst, kernelSizeY, dyLeft, dyRight, stride, 4, paintSize.height(), paintSize.width(), isAlphaImage());
            swap(src, dst);
        }
    }

    // The final result should be stored in srcPixelArray.
    if (dst == srcPixelArray) {
        ASSERT(src->length() == dst->length());
        memcpy(dst->data(), src->data(), src->length());
    }

}

void FilterEffect::forceValidPreMultipliedPixels()
{
    // Must operate on pre-multiplied results; other formats cannot have invalid pixels.
    if (!m_premultipliedImageResult)
        return;

    Uint8ClampedArray* imageArray = m_premultipliedImageResult.get();
    unsigned char* pixelData = imageArray->data();
    int pixelArrayLength = imageArray->length();

    // We must have four bytes per pixel, and complete pixels
    ASSERT(!(pixelArrayLength % 4));

#if HAVE(ARM_NEON_INTRINSICS)
    if (pixelArrayLength >= 64) {
        unsigned char* lastPixel = pixelData + (pixelArrayLength & ~0x3f);
        do {
            // Increments pixelData by 64.
            uint8x16x4_t sixteenPixels = vld4q_u8(pixelData);
            sixteenPixels.val[0] = vminq_u8(sixteenPixels.val[0], sixteenPixels.val[3]);
            sixteenPixels.val[1] = vminq_u8(sixteenPixels.val[1], sixteenPixels.val[3]);
            sixteenPixels.val[2] = vminq_u8(sixteenPixels.val[2], sixteenPixels.val[3]);
            vst4q_u8(pixelData, sixteenPixels);
            pixelData += 64;
        } while (pixelData < lastPixel);

        pixelArrayLength &= 0x3f;
        if (!pixelArrayLength)
            return;
    }
#endif

    int numPixels = pixelArrayLength / 4;

    // Iterate over each pixel, checking alpha and adjusting color components if necessary
    while (--numPixels >= 0) {
        // Alpha is the 4th byte in a pixel
        unsigned char a = *(pixelData + 3);
        // Clamp each component to alpha, and increment the pixel location
        for (int i = 0; i < 3; ++i) {
            if (*pixelData > a)
                *pixelData = a;
            ++pixelData;
        }
        // Increment for alpha
        ++pixelData;
    }
}

void FEComponentTransfer::platformApplySoftware()
{
    FilterEffect* in = inputEffect(0);

    Uint8ClampedArray* pixelArray = createUnmultipliedImageResult();
    if (!pixelArray)
        return;

    unsigned char rValues[256], gValues[256], bValues[256], aValues[256];
    getValues(rValues, gValues, bValues, aValues);
    unsigned char* tables[] = { rValues, gValues, bValues, aValues };

    IntRect drawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
    in->copyUnmultipliedImage(pixelArray, drawingRect);

    unsigned pixelArrayLength = pixelArray->length();
    for (unsigned pixelOffset = 0; pixelOffset < pixelArrayLength; pixelOffset += 4) {
        for (unsigned channel = 0; channel < 4; ++channel) {
            unsigned char c = pixelArray->item(pixelOffset + channel);
            pixelArray->set(pixelOffset + channel, tables[channel][c]);
        }
    }
}

void FECustomFilter::platformApplySoftware()
{
    Uint8ClampedArray* dstPixelArray = createPremultipliedImageResult();
    if (!dstPixelArray)
        return;

    FilterEffect* in = inputEffect(0);
    IntRect effectDrawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
    RefPtr<Uint8ClampedArray> srcPixelArray = in->asPremultipliedImage(effectDrawingRect);
    
    IntSize newContextSize(effectDrawingRect.size());
    bool hadContext = m_context;
    if (!m_context)
        initializeContext();
    
    if (!hadContext || m_contextSize != newContextSize)
        resizeContext(newContextSize);

    // Do not draw the filter if the input image cannot fit inside a single GPU texture.
    if (m_inputTexture->tiles().numTilesX() != 1 || m_inputTexture->tiles().numTilesY() != 1)
        return;
    
    // The shader had compiler errors. We cannot draw anything.
    if (!m_shader->isInitialized())
        return;

    m_context->bindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_frameBuffer);
    m_context->viewport(0, 0, newContextSize.width(), newContextSize.height());
    
    m_context->clearColor(0, 0, 0, 0);
    m_context->clear(GraphicsContext3D::COLOR_BUFFER_BIT | GraphicsContext3D::DEPTH_BUFFER_BIT);
    
    bindProgramAndBuffers(srcPixelArray.get());
    
    m_context->drawElements(GraphicsContext3D::TRIANGLES, m_mesh->indicesCount(), GraphicsContext3D::UNSIGNED_SHORT, 0);
    
    ASSERT(static_cast<size_t>(newContextSize.width() * newContextSize.height() * 4) == dstPixelArray->length());
    m_context->readPixels(0, 0, newContextSize.width(), newContextSize.height(), GraphicsContext3D::RGBA, GraphicsContext3D::UNSIGNED_BYTE, dstPixelArray->data());
}