vp8l

Documentation

Overview

Package vp8l implements a pure-Go VP8L (WebP lossless) encoder.

The bitstream is decoded by golang.org/x/image/webp; this package is the matching encoder. Coverage today is Phase A — literal-only emission with canonical Huffman codes per channel and no transforms. Phase B (subtract-green) and Phase C (LZ77 + color cache) extend the encoder without changing this public API.

This package is internal because the only intended entry point is framework/image.Image.WebP() (zero-value WebPOptions = lossless).

Index

• func Encode(w io.Writer, m image.Image) error

Functions

func Encode

func Encode(w io.Writer, m image.Image) error

Encode writes m as a VP8L WebP to w. Only m's bounds are honoured; callers needing other-than-RGBA must convert first (which the framework/image package does automatically).

Lossless guarantee: the decoded pixels equal the input pixels exactly when m's bounds are non-empty. An empty image returns an error rather than producing an empty WebP.