Go Resizing Images

Question

I am using the Go resize package here: https://github.com/nfnt/resize

1. I am pulling an Image from S3, as such:

   image_data, err := mybucket.Get(ke         
   
   
           

Answer 1

Want to do it 29 times faster? Try amazing vipsthumbnail instead:

sudo apt-get install libvips-tools
vipsthumbnail --help-all

This will resize and nicely crop saving result to a file:

vipsthumbnail original.jpg -s 700x200 -o 700x200.jpg -c

Calling from Go:

func resizeExternally(from string, to string, width uint, height uint) error {
    var args = []string{
        "--size", strconv.FormatUint(uint64(width), 10) + "x" +
            strconv.FormatUint(uint64(height), 10),
        "--output", to,
        "--crop",
        from,
    }
    path, err := exec.LookPath("vipsthumbnail")
    if err != nil {
        return err
    }
    cmd := exec.Command(path, args...)
    return cmd.Run()
}

Answer 2

You could use bimg, which is powered by libvips (a fast image processing library written in C).

If you are looking for a image resizing solution as a service, take a look to imaginary

Answer 3

Read http://golang.org/pkg/image

// you need the image package, and a format package for encoding/decoding
import (
    "bytes"
    "image"
    "image/jpeg" // if you don't need to use jpeg.Encode, use this line instead 
    // _ "image/jpeg"

    "github.com/nfnt/resize"

    
)

// Decoding gives you an Image.
// If you have an io.Reader already, you can give that to Decode 
// without reading it into a []byte.
image, _, err := image.Decode(bytes.NewReader(data))
// check err

newImage := resize.Resize(160, 0, original_image, resize.Lanczos3)

// Encode uses a Writer, use a Buffer if you need the raw []byte
err = jpeg.Encode(someWriter, newImage, nil)
// check err