blur

Documentation

Overview

Package blur provides a fast separable blur used as a primitive by the effects package. It approximates a Gaussian with three successive box blurs, a well-known technique: three boxes converge to within a visually indistinct error of a true Gaussian, and each box blur is O(n) per pixel via a sliding window, independent of radius. Both passes parallelize across fixed bands so the result is deterministic.

Index

• func BoxBlur(b *raster.Buffer, radius int)
• func Gaussian(b *raster.Buffer, sigma float32)

Functions

func BoxBlur

func BoxBlur(b *raster.Buffer, radius int)

BoxBlur applies a single box blur of the given pixel radius in place, exposed for callers that want the cheaper primitive directly

func Gaussian

func Gaussian(b *raster.Buffer, sigma float32)

Gaussian blurs the buffer in place, approximating a Gaussian of standard deviation sigma pixels. It operates on premultiplied channels, which is what shadow and glow effects need. A non-positive sigma is a no-op.