void FEDropShadow::determineAbsolutePaintRect()
{
    Filter* filter = this->filter();
    ASSERT(filter);

    FloatRect absolutePaintRect = inputEffect(0)->absolutePaintRect();
    FloatRect absoluteOffsetPaintRect(absolutePaintRect);
    absoluteOffsetPaintRect.move(filter->applyHorizontalScale(m_dx), filter->applyVerticalScale(m_dy));
    absolutePaintRect.unite(absoluteOffsetPaintRect);
    
    unsigned kernelSizeX = 0;
    unsigned kernelSizeY = 0;
    FEGaussianBlur::calculateKernelSize(filter, kernelSizeX, kernelSizeY, m_stdX, m_stdY);
    
    // We take the half kernel size and multiply it with three, because we run box blur three times.
    absolutePaintRect.inflateX(3 * kernelSizeX * 0.5f);
    absolutePaintRect.inflateY(3 * kernelSizeY * 0.5f);

    if (clipsToBounds())
        absolutePaintRect.intersect(maxEffectRect());
    else
        absolutePaintRect.unite(maxEffectRect());

    setAbsolutePaintRect(enclosingIntRect(absolutePaintRect));
}
void FEDropShadow::determineAbsolutePaintRect()
{
    Filter& filter = this->filter();

    FloatRect absolutePaintRect = inputEffect(0)->absolutePaintRect();
    FloatRect absoluteOffsetPaintRect(absolutePaintRect);
    absoluteOffsetPaintRect.move(filter.applyHorizontalScale(m_dx), filter.applyVerticalScale(m_dy));
    absolutePaintRect.unite(absoluteOffsetPaintRect);

    IntSize kernelSize = FEGaussianBlur::calculateKernelSize(filter, FloatPoint(m_stdX, m_stdY));

    // We take the half kernel size and multiply it with three, because we run box blur three times.
    absolutePaintRect.inflateX(3 * kernelSize.width() * 0.5f);
    absolutePaintRect.inflateY(3 * kernelSize.height() * 0.5f);

    if (clipsToBounds())
        absolutePaintRect.intersect(maxEffectRect());
    else
        absolutePaintRect.unite(maxEffectRect());

    setAbsolutePaintRect(enclosingIntRect(absolutePaintRect));
}