sk_sp<SkImageFilter> FEConvolveMatrix::createImageFilter() {
if (!parametersValid())
return createTransparentBlack();
sk_sp<SkImageFilter> input(
SkiaImageFilterBuilder::build(inputEffect(0), operatingColorSpace()));
SkISize kernelSize(
SkISize::Make(m_kernelSize.width(), m_kernelSize.height()));
// parametersValid() above checks that the kernel area fits in int.
int numElements = safeCast<int>(m_kernelSize.area());
SkScalar gain = SkFloatToScalar(1.0f / m_divisor);
SkScalar bias = SkFloatToScalar(m_bias * 255);
SkIPoint target = SkIPoint::Make(m_targetOffset.x(), m_targetOffset.y());
SkMatrixConvolutionImageFilter::TileMode tileMode =
toSkiaTileMode(m_edgeMode);
bool convolveAlpha = !m_preserveAlpha;
std::unique_ptr<SkScalar[]> kernel =
wrapArrayUnique(new SkScalar[numElements]);
for (int i = 0; i < numElements; ++i)
kernel[i] = SkFloatToScalar(m_kernelMatrix[numElements - 1 - i]);
SkImageFilter::CropRect cropRect = getCropRect();
return SkMatrixConvolutionImageFilter::Make(
kernelSize, kernel.get(), gain, bias, target, tileMode, convolveAlpha,
std::move(input), &cropRect);
}
FloatRect FEConvolveMatrix::mapEffect(const FloatRect& rect) const {
if (!parametersValid())
return rect;
FloatRect result = rect;
result.moveBy(-m_targetOffset);
result.expand(FloatSize(m_kernelSize));
return result;
}
FloatRect FEConvolveMatrix::mapPaintRect(const FloatRect& rect, bool forward)
{
FloatRect result = rect;
if (parametersValid()) {
result.moveBy(forward ? -m_targetOffset : m_targetOffset - m_kernelSize);
result.expand(m_kernelSize);
}
return result;
}
