static int clampedToKernelSize(float value)
{
// Limit the kernel size to 500. A bigger radius won't make a big difference for the result image but
// inflates the absolute paint rect too much. This is compatible with Firefox' behavior.
unsigned size = std::max<unsigned>(2, static_cast<unsigned>(floorf(value * gaussianKernelFactor() + 0.5f)));
return clampTo<int>(std::min(size, static_cast<unsigned>(gMaxKernelSize)));
}
void FEGaussianBlur::calculateUnscaledKernelSize(unsigned& kernelSizeX, unsigned& kernelSizeY, float stdX, float stdY)
{
kernelSizeX = 0;
if (stdX)
kernelSizeX = max<unsigned>(2, static_cast<unsigned>(floorf(stdX * gaussianKernelFactor() + 0.5f)));
kernelSizeY = 0;
if (stdY)
kernelSizeY = max<unsigned>(2, static_cast<unsigned>(floorf(stdY * gaussianKernelFactor() + 0.5f)));
// Limit the kernel size to 1000. A bigger radius won't make a big difference for the result image but
// inflates the absolute paint rect to much. This is compatible with Firefox' behavior.
if (kernelSizeX > gMaxKernelSize)
kernelSizeX = gMaxKernelSize;
if (kernelSizeY > gMaxKernelSize)
kernelSizeY = gMaxKernelSize;
}
IntSize FEGaussianBlur::calculateUnscaledKernelSize(const FloatPoint& std)
{
ASSERT(std.x() >= 0 && std.y() >= 0);
IntSize kernelSize;
// Limit the kernel size to 1000. A bigger radius won't make a big difference for the result image but
// inflates the absolute paint rect to much. This is compatible with Firefox' behavior.
if (std.x()) {
int size = std::max<unsigned>(2, static_cast<unsigned>(floorf(std.x() * gaussianKernelFactor() + 0.5f)));
kernelSize.setWidth(std::min(size, gMaxKernelSize));
}
if (std.y()) {
int size = std::max<unsigned>(2, static_cast<unsigned>(floorf(std.y() * gaussianKernelFactor() + 0.5f)));
kernelSize.setHeight(std::min(size, gMaxKernelSize));
}
return kernelSize;
}
float FEGaussianBlur::calculateStdDeviation(float radius)
{
// Blur radius represents 2/3 times the kernel size, the dest pixel is half of the radius applied 3 times
return max((radius * 2 / 3.f - 0.5f) / gaussianKernelFactor(), 0.f);
}
