README
¶
webp
Go encoder/decoder for WebP Image File Format with support for animated WebP images (decode only).
Based on libwebp compiled to WASM and used with wazero runtime (CGo-free).
The library will first try to use a dynamic/shared library (if installed) via purego and will fall back to WASM.
Build tags
nodynamic- do not use dynamic/shared library (use only WASM)
Benchmark
goos: linux
goarch: amd64
pkg: github.com/gen2brain/webp
cpu: 11th Gen Intel(R) Core(TM) i7-1185G7 @ 3.00GHz
BenchmarkDecodeStd-8 157 7639585 ns/op 473683 B/op 13 allocs/op
BenchmarkDecodeWasm-8 156 7799653 ns/op 2614793 B/op 316 allocs/op
BenchmarkDecodeDynamic-8 344 3497863 ns/op 943356 B/op 58 allocs/op
BenchmarkDecodeTranspiled-8 (1) 138 8562133 ns/op 1335622 B/op 52 allocs/op
BenchmarkDecodeCGo1-8 (2) 300 3897300 ns/op 1333630 B/op 21 allocs/op
BenchmarkDecodeCGo2-8 (3) 314 3801195 ns/op 1334020 B/op 22 allocs/op
BenchmarkEncodeWasm-8 12 96123599 ns/op 4857356 B/op 298 allocs/op
BenchmarkEncodeDynamic-8 55 19022243 ns/op 19888 B/op 42 allocs/op
BenchmarkEncodeTranspiled-8 (1) 18 60042805 ns/op 76104 B/op 36 allocs/op
BenchmarkEncodeCGo1-8 (2) 31 32538122 ns/op 3213497 B/op 524294 allocs/op
BenchmarkEncodeCGo2-8 (3) 52 22482704 ns/op 26043 B/op 5 allocs/op
Documentation
¶
Overview ¶
Package webp implements an WEBP image decoder based on libwebp compiled to WASM.
Index ¶
- Constants
- Variables
- func Decode(r io.Reader) (image.Image, error)
- func DecodeConfig(r io.Reader) (image.Config, error)
- func Dynamic() error
- func Encode(w io.Writer, m image.Image, o ...Options) error
- func EncodeAll(w io.Writer, images []image.Image, o ...Options) error
- func Init()
- type Options
- type WEBP
Constants ¶
const DefaultDisposal = 0
DefaultDisposal is the default duration for animations.
const DefaultDuration = 50
DefaultDuration is the default duration for animations.
const DefaultMethod = 4
DefaultMethod is the default method encoding parameter.
const DefaultQuality = 75
DefaultQuality is the default quality encoding parameter.
Variables ¶
var ( ErrMemRead = errors.New("webp: mem read failed") ErrMemWrite = errors.New("webp: mem write failed") ErrDecode = errors.New("webp: decode failed") ErrEncode = errors.New("webp: encode failed") )
Errors .
Functions ¶
func DecodeConfig ¶
DecodeConfig returns the color model and dimensions of a WEBP image without decoding the entire image.
func Dynamic ¶
func Dynamic() error
Dynamic returns error (if there was any) during opening dynamic/shared library.
Types ¶
type Options ¶
type Options struct {
// Quality in the range [0,100]. Quality of 100 implies Lossless. Default is 75.
Quality int
// Lossless indicates whether to use the lossless compression. Lossless will ignore quality.
Lossless bool
// Method is quality/speed trade-off (0=fast, 6=slower-better). Default is 4.
Method int
// Exact preserve the exact RGB values in transparent area.
Exact bool
// UseExtendedFormat allows for metadata support. Only used for encoding
// animated images.
UseExtendedFormat bool
// Durations times, one per frame, in milliseconds.
Durations []int
// Disposals methods for frames after display; 0=keep, 1=clear to background.
Disposals []int
// LoopCount the number of times the animation loops; 0 for infinite.
LoopCount int
}
Options are the encoding parameters.
type WEBP ¶
type WEBP struct {
// Decoded images.
Image []image.Image
// Durations times, one per frame, in milliseconds.
Durations []int
// Disposals methods for frames after display; 0=keep, 1=clear to background.
Disposals []int
// LoopCount the number of times the animation loops; 0 for infinite.
LoopCount int
}
WEBP represents the possibly multiple images stored in a WEBP file.
Source Files