README
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jpegxl
Go encoder/decoder for JPEG XL Image File Format with support for animated JXL images (decode only).
Based on libjxl 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)wasm2go- transpile WASM to Go instead of using wazero; decodes with jxl-rs and encodes losslessly with zune-jpegxl
Documentation
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Overview ¶
Package jpegxl implements an JPEG XL image decoder based on libjxl compiled to WASM.
Index ¶
Constants ¶
const DefaultEffort = 7
DefaultEffort is the default effort encoding parameter.
const DefaultQuality = 75
DefaultQuality is the default quality encoding parameter.
Variables ¶
var ( ErrMemRead = errors.New("jpegxl: mem read failed") ErrMemWrite = errors.New("jpegxl: mem write failed") ErrDecode = errors.New("jpegxl: decode failed") ErrEncode = errors.New("jpegxl: encode failed") )
Errors .
var ErrNoExif = errors.New("jpegxl: no exif data")
ErrNoExif is returned by DecodeExif when the JPEG XL has no Exif box.
Functions ¶
func DecodeConfig ¶
DecodeConfig returns the color model and dimensions of a JPEG XL image without decoding the entire image.
func Dynamic ¶ added in v0.2.1
func Dynamic() error
Dynamic returns error (if there was any) during opening dynamic/shared library.
func InitDecoder ¶ added in v0.4.1
func InitDecoder()
InitDecoder initializes wazero runtime and compiles the module. This function does nothing if a dynamic/shared library is used and Dynamic() returns nil. There is no need to explicitly call this function, first Decode will initialize the runtime.
func InitEncoder ¶ added in v0.4.1
func InitEncoder()
InitEncoder initializes wazero runtime and compiles the module. This function does nothing if a dynamic/shared library is used and Dynamic() returns nil. There is no need to explicitly call this function, first Encode will initialize the runtime.
Types ¶
type Exif ¶ added in v0.5.3
type Exif struct {
// Basic image info
Orientation int // EXIF orientation (1-8). 1 = normal, values 2-8 indicate rotation/flip.
Width int // Image width in pixels.
Height int // Image height in pixels.
// Camera info
Make string // Camera manufacturer (e.g., "Canon").
Model string // Camera model (e.g., "Canon EOS 5D Mark III").
Software string // Software used to process/create the image.
// Date/Time (format: "YYYY:MM:DD HH:MM:SS")
DateTime string // File modification date/time.
DateTimeOriginal string // Original capture date/time (when photo was taken).
// Exposure settings
ExposureTime float64 // Shutter speed in seconds (e.g., 0.004 = 1/250s).
FNumber float64 // Aperture f-number (e.g., 5.6 = f/5.6).
ISOSpeed int // ISO speed rating (e.g., 800).
FocalLength float64 // Lens focal length in millimeters.
Flash int // Flash mode/status (0 = no flash, non-zero = flash fired).
// GPS location
GPSLatitude float64 // Latitude in decimal degrees (positive = North, negative = South).
GPSLongitude float64 // Longitude in decimal degrees (positive = East, negative = West).
GPSAltitude float64 // Altitude in meters above sea level.
// Copyright/Author
Copyright string // Copyright notice.
Artist string // Creator/photographer name.
}
Exif holds the EXIF metadata decoded from a JPEG XL image.
type JXL ¶ added in v0.1.4
type JXL struct {
// Decoded images, NRGBA or NRGBA64.
Image []image.Image
// Delay times, one per frame, in seconds of a tick.
Delay []int
}
JXL represents the possibly multiple images stored in a JXL file.
type Options ¶ added in v0.2.4
type Options struct {
// Quality in the range [0,100]. Default is 75.
Quality int
// Effort in the range [1,10]. Sets encoder effort/speed level without affecting decoding speed. Default is 7.
Effort int
// Lossless enables lossless compression. Lossless ignores quality.
Lossless bool
}
Options are the encoding parameters.
Source Files