img

package
v0.0.0-...-85bfd8b Latest Latest
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 Go to latest Published: Jan 22, 2026 License: AGPL-3.0 Imports: 20 Imported by: 0

Documentation

Overview

Package img provides a unified image loader and manipulation pipeline. It can load images using the native go implementations for the major web image types, perform some manipulation like resizing and write the result to an io.Writer.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func AddImageHandler 

func AddImageHandler(f Handler, types ...string)

AddImageHandler adds (or replaces) a handler for the given types.

func Fit 

func Fit(im Image, w, h uint) error

Fit resizes the image keeping the aspect ratio and staying within the given width and height.

func Pipeline 

func Pipeline(im Image, filters ...ImageFilter) error

Pipeline apply all the given ImageFilter functions to the image.

Types

type GIFImage 

type GIFImage struct {
	*gif.GIF
	// contains filtered or unexported fields
}

GIFImage is the Image implementation for GIF files only.

func NewGIFImage 

func NewGIFImage(r io.Reader) (*GIFImage, error)

NewGIFImage returns a GIFImage instance that decodes all frames from a GIF image.

func (*GIFImage) Clean 

func (im *GIFImage) Clean() error

Clean is a noop function for this image family.

func (*GIFImage) Close 

func (im *GIFImage) Close() error

Close frees the resources used by the image and must be called when you're done processing it.

func (*GIFImage) ContentType 

func (im *GIFImage) ContentType() string

ContentType returns the image mimetype.

func (*GIFImage) Encode 

func (im *GIFImage) Encode(w io.Writer) (string, error)

Encode encodes the image to an io.Writer.

func (*GIFImage) FirstFrame 

func (im *GIFImage) FirstFrame() Image

FirstFrame returns the first GIF's image as an Image.

func (*GIFImage) Format 

func (im *GIFImage) Format() string

Format returns the image format.

func (*GIFImage) Frames 

func (im *GIFImage) Frames() uint

Frames returns the image's number of frames.

func (*GIFImage) Height 

func (im *GIFImage) Height() uint

Height returns the image height.

func (*GIFImage) Resize 

func (im *GIFImage) Resize(w, h uint) error

Resize resizes the image to the given width and height.

func (*GIFImage) SetCompression 

func (im *GIFImage) SetCompression(c ImageCompression) error

SetCompression sets the compression level of PNG endoding.

func (*GIFImage) SetFormat 

func (im *GIFImage) SetFormat(_ string) error

SetFormat is a noop function for this image family.

func (*GIFImage) SetQuality 

func (im *GIFImage) SetQuality(_ uint8) error

SetQuality is a noop function for this image family.

func (*GIFImage) Width 

func (im *GIFImage) Width() uint

Width returns the image width.

type Handler 

type Handler func(io.Reader) (Image, error)

Handler is a function that returns an Image type instance from an io.Reader.

type Image 

type Image interface {
	Close() error
	Format() string
	ContentType() string
	Width() uint
	Height() uint
	SetFormat(string) error
	Resize(uint, uint) error
	Encode(io.Writer) (string, error)
	SetCompression(ImageCompression) error
	SetQuality(uint8) error
	Clean() error
}

Image describes the interface of an image manipulation type.

func New 

func New(contentType string, r io.Reader) (Image, error)

New creates a new Image instance, using the available handlers.

type ImageCompression 

type ImageCompression uint8

ImageCompression is the compression level used for PNG images. 

const (
	// CompressionFast is a fast method.
	CompressionFast ImageCompression = iota

	// CompressionBest is the best space saving method.
	CompressionBest
)

type ImageFilter 

type ImageFilter func(Image) error

ImageFilter is a filter application function used by the Pipeline method of an Image instance.

type MultiFrameImage 

type MultiFrameImage interface {
	Image
	Frames() uint
	FirstFrame() Image
}

MultiFrameImage describes the interface of an image with multiple frames, such as animated GIFs.

type NativeImage 

type NativeImage struct {
	// contains filtered or unexported fields
}

NativeImage is the Image implementation using Go native image tools.

func NewNativeImage 

func NewNativeImage(r io.Reader) (*NativeImage, error)

NewNativeImage returns a NativeImage instance using Go native image tools.

func (*NativeImage) Clean 

func (im *NativeImage) Clean() error

Clean is a noop function for this image family.

func (*NativeImage) Close 

func (im *NativeImage) Close() error

Close frees the resources used by the image and must be called when you're done processing it.

func (*NativeImage) ContentType 

func (im *NativeImage) ContentType() string

ContentType returns the image mimetype.

func (*NativeImage) Encode 

func (im *NativeImage) Encode(w io.Writer) (string, error)

Encode encodes the image to an io.Writer.

func (*NativeImage) Format 

func (im *NativeImage) Format() string

Format returns the image format.

func (*NativeImage) Height 

func (im *NativeImage) Height() uint

Height returns the image height.

func (*NativeImage) Image 

func (im *NativeImage) Image() image.Image

Image returns the wrapped image instance.

func (*NativeImage) Resize 

func (im *NativeImage) Resize(w, h uint) error

Resize resizes the image to the given width and height.

func (*NativeImage) SetCompression 

func (im *NativeImage) SetCompression(c ImageCompression) error

SetCompression sets the compression level of PNG encoding.

func (*NativeImage) SetFormat 

func (im *NativeImage) SetFormat(f string) error

SetFormat sets the encoding format. When none is set, it will use the original format or fallback to JPEG.

func (*NativeImage) SetQuality 

func (im *NativeImage) SetQuality(q uint8) error

SetQuality sets the quality of JEPG encoding.

func (*NativeImage) Width 

func (im *NativeImage) Width() uint

Width returns the image width.

type SvgImage 

type SvgImage struct {
	// contains filtered or unexported fields
}

SvgImage is the Image implementation for SVG images.

func NewSvgImage 

func NewSvgImage(r io.Reader) (*SvgImage, error)

NewSvgImage returns an SvgImage instance.

func (*SvgImage) Clean 

func (im *SvgImage) Clean() error

Clean sanitizes the SVG image by keeping only a specific set of tags and attributes.

func (*SvgImage) Close 

func (im *SvgImage) Close() error

Close is a noop here.

func (*SvgImage) ContentType 

func (im *SvgImage) ContentType() string

ContentType returns the image mimetype.

func (*SvgImage) Encode 

func (im *SvgImage) Encode(w io.Writer) (string, error)

Encode encodes the image to an io.Writer.

func (*SvgImage) Format 

func (im *SvgImage) Format() string

Format returns the image format.

func (*SvgImage) Gray16 

func (im *SvgImage) Gray16() error

Gray16 is a noop here.

func (*SvgImage) Grayscale 

func (im *SvgImage) Grayscale() error

Grayscale is a noop here.

func (*SvgImage) Height 

func (im *SvgImage) Height() uint

Height returns the image height.

func (*SvgImage) Resize 

func (im *SvgImage) Resize(w, h uint) error

Resize resizes the image to the given width and height.

func (*SvgImage) SetCompression 

func (im *SvgImage) SetCompression(ImageCompression) error

SetCompression is a noop here.

func (*SvgImage) SetFormat 

func (im *SvgImage) SetFormat(string) error

SetFormat is a noop here.

func (*SvgImage) SetQuality 

func (im *SvgImage) SetQuality(uint8) error

SetQuality is a noop here.

func (*SvgImage) Width 

func (im *SvgImage) Width() uint

Width returns the image width.

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