gaussian Blur Convolve
Return an instance of TextureOp which implements a convolution from the source texture to the destination texture provided a Gaussian blur effect for textures, and its convolve kernel conforms to the Gaussian distribution with sum of 1, and the kernel is a 3 * 3 matrix, and the length should be odd.
For the edge pixels of the image, the default value of missing pixels within the convolution radius is set to 0 when performing convolution operations.
Return
an instance of TextureOp which implements a convolution from the source texture to the destination.
Parameters
factor
the factor of the transparency and brightness.
length
the length of the kernel.