image

README

go-image

There are many "wrapper" packages for working with images in Go. This one is mine.

Important

These are image tools that I wrote by and for myself tailored to the needs of personal projects. It's possible they are not the image tools you need or want.

Documentation

Example

package main

import (
	"context"
	"flag"
	"os"

	"github.com/aaronland/go-image/v2/decode"
	"github.com/aaronland/go-image/v2/encode"
	"github.com/aaronland/go-image/v2/exif"
)

func main() {

	flag.Parse()

	ctx := context.Background()

	decode_opts := &decode.DecodeImageOptions{
		Rotate: true,
	}		  
		    
	for _, path := range flag.Args() {

		r, _ := os.Open(path)
		defer r.Close()

		im, _, ifd, _ := decode.DecodeImageWithOptions(ctx, r, decode_opts)
		ib, _ := exif.NewIfdBuilderWithOrientation(ifd, "1")

		new_path := fmt.Sprintf("%s.jpg", path)
		wr, _ := os.OpenFile(new_path, os.O_RDWR|os.O_CREATE, 0644)

		encode.EncodeJPEG(ctx, wr, im, ib, nil)
		wr.Close()
	}
}

Error handling removed for the sake of brevity.

Tools

$> make cli TAGS=libheif
go build -mod vendor -ldflags="-s -w" -tags libheif -o bin/transform cmd/transform/main.go
go build -mod vendor -ldflags="-s -w" -tags libheif -o bin/resize cmd/resize/main.go

resize

Resize one or more images.

$> ./bin/resize -h
Resize one or more images.
Usage:
	./bin/resize uri(N) uri(N)
  -max int
    	The maximum dimension of the resized image
  -preserve-exif
    	Copy EXIF data from source image final target image.
  -profile string
    	An optional colour profile to apply to the resized image. Valid options are: adobergb, displayp3.
  -rotate
    	Automatically rotate based on EXIF orientation. This does NOT update any of the original EXIF data with one exception: If the -rotate flag is true OR the original image of type HEIC then the EXIF "Orientation" tag is re-written to be "1". (default true)
  -source-uri string
    	A valid gocloud.dev/blob.Bucket URI where images are read from. (default "file:///")
  -target-uri string
    	A valid gocloud.dev/blob.Bucket URI where images are written to. (default "file:///")
  -transformation-uri transform.Transformation
    	Zero or more additional transform.Transformation URIs used to further modify an image after resizing (and before any additional colour profile transformations are performed).

Example

Create a new JPEG image with a maximum dimension of 640 pixels and no EXIF data at ./fixtures/tokyo-1280.jpg.

$> ./bin/resize -max 640 ./fixtures/tokyo.jpg

transform

Transform one or more images applying one or more transform:// transformation URIs.

$> ./bin/transform -h
Transform one or more images applying one or more transform:// transformation URIs.
Usage:
	./bin/transform uri(N) uri(N)
  -apply-suffix string
    	An optional suffix to apply to the final image filename.
  -format string
    	An optional image format used to encode the final image.
  -preserve-exif
    	Copy EXIF data from source image final target image.
  -rotate
    	Automatically rotate based on EXIF orientation. This does NOT update any of the original EXIF data with one exception: If the -rotate flag is true OR the original image of type HEIC then the EXIF "Orientation" tag is re-written to be "1". (default true)
  -source-uri string
    	A valid gocloud.dev/blob.Bucket URI where images are read from. (default "file:///")
  -target-uri string
    	A valid gocloud.dev/blob.Bucket URI where images are written to. (default "file:///")
  -transformation-uri transform.Transformation
    	One or more additional transform.Transformation URIs used to further modify an image after resizing (and before any additional colour profile transformations are performed).

Example

Create a new PNG image with the Apple DisplayP3 colour profile and a maximum dimension of 1280 pixels at ./fixtures/tokyo-1280.png

$> go run cmd/transform/main.go \
	-transformation-uri 'resize://?max=1280' \
	-transformation-uri displayp3:// \
	-apply-suffix -1280 \
	-preserve-exif \
	-format png \
	./fixtures/tokyo.jpg

Decoders

The following image decoders are supported by default:

• image/bmp
• image/gif
• image/heic (if built with libheif tag)
• image/jpeg
• image/png
• image/tiff
• image/webp

HEIC images

By default this package supports decoding HEIC images using the strukturag/libheif-go package which, in turn, depends on the presence of the libheif library but when you are compiling your code (or the command line tools) you will need to pass in the -tags libheif flag.

Encoders

• image/bmp
• image/heic (if built with libheif tag)
• image/jpeg
• image/png
• image/tiff

HEIC images

By default this package supports encoding HEIC images using the strukturag/libheif-go package which, in turn, depends on the presence of the libheif library but when you are compiling your code (or the command line tools) you will need to pass in the -tags libheif flag.

Documentation

Overview

Package image provides methods for working with images. There are many image "wrapper" in Go, this one is mine.