src,err := imagehash.OpenImg("./testdata/lena_512.png")

// The hashes are returned as byte arrays
//
// Calculate both horizontal & vertical gradients, then return them
// concatenated together as <horizontal><vertical>
hash,err  := imagehash.Dhash(src, hashLen)

// Calculate only the horizontal gradient difference
hashH,err := imagehash.DhashHorizontal(src, hashLen)

// Calculate only the vertical gradient difference
hashV,err := imagehash.DhashVertical(src, hashLen)

package main

import (
  "fmt"
  "encoding/hex"  // To transform the byte array to hex
  "github.com/devedge/imagehash"
)

func main() {
  src,_ := imagehash.OpenImg("./testdata/lena_512.png")

  // The length of a downscaled side. It must be > 8, and
  // (hashLen * hashLen) must be a multiple of 8
  hashLen := 8
  // A value of 8 will return 64 bits, or 8 bytes / 16 hex characters
  // (64 bits = 8 bits length * 8 bits width)

  hash,_ := imagehash.Dhash(src, hashLen)
  hashH,_ := imagehash.DhashHorizontal(src, hashLen)
  hashV,_ := imagehash.DhashVertical(src, hashLen)

  fmt.Println("dhash:           ", hex.EncodeToString(hash))
  fmt.Println("Horizontal dhash:", hex.EncodeToString(hashH))
  fmt.Println("Vertical dhash:  ", hex.EncodeToString(hashV))
}

// The hash is returned as a byte array
hash,err := imagehash.Ahash(src, hashLen)

package main

import (
  "fmt"
  "encoding/hex"
  "github.com/devedge/imagehash"
  "github.com/steakknife/hamming"
)

func main() {
  src512,_ := imagehash.OpenImg("./testdata/lena_512.png")
  src256,_ := imagehash.OpenImg("./testdata/lena_256.png")
  srcInv,_ := imagehash.OpenImg("./testdata/lena_inverted_512.png")

  hash512,_ := imagehash.Dhash(src512, 8)
  hash256,_ := imagehash.Dhash(src256, 8)
  hashInv,_ := imagehash.Dhash(srcInv, 8)

  // Hamming distance of 0, since the images are simply different sizes
  fmt.Println("'lena_512.png' dhash:", hex.EncodeToString(hash512))
  fmt.Println("'lena_256.png' dhash:", hex.EncodeToString(hash256))
  fmt.Println("The Hamming distance between these:", hamming.Bytes(hash512, hash256))
  fmt.Println()

  // Completely different dhash, since an inverted image has a completely
  // different gradient colorscheme
  fmt.Println("'lena_512.png' dhash:         ", hex.EncodeToString(hash512))
  fmt.Println("'lena_inverted_512.png' dhash:", hex.EncodeToString(hashInv))
  fmt.Println("The Hamming distance between these:", hamming.Bytes(hash512, hashInv))
}