Gaussian Blur Filter
The Gaussian Blur Filter convolves the image with a gaussian filter function. This produces a very smooth blur effect.
The "Radius" parameter controls how much the image gets blurred. It specified the standard deviation of the gaussian filter kernel.
The "Shape" parameter allows you to control how much the image gets blurred in each direction.
Shape = 0 blurs the image equally in all directions.
Shape = +1 produces a vertical blur.
Shape = -1 produces a horizontal blur.
Accuracy depends on the current image format. If you need higher accuracy, increase the document's color depth