buckket / go-blurhash Goto Github PK

Hello! I am using the library and have been for a while, but I've noticed for a while that it produces different (and arguably worse) results than the website implementation at blurha.sh

Please see my reference images. Any idea what could be going wrong?

Here is the generated blur hash and the difference in results:
LTIXH#ai5XRo0xRRnzR-4.M}-$V[

This library has the Encode API take in a pointer to image.Image (*image.Image) instead of either the interface itself (which has an underlying value of a pointer) or a concrete struct such as *image.NRGBA. This is usually a bad idea.

The lines that use this "pointer to interface" seem to only dereference the interface and not change it:

https://github.com/buckket/go-blurhash/blob/master/encode.go#L110-L111

height := (*rgba).Bounds().Max.Y
width := (*rgba).Bounds().Max.X

https://github.com/buckket/go-blurhash/blob/master/encode.go#L131

rt, gt, bt, _ := (*rgba).At(x, y).RGBA()

The library panics in case of uploading a broken image.

Relates to disintegration/imaging#165

Minimal reproducible example

• poc.tiff by @pic4xiu
• main.go

  package main
  
  import (
      "fmt"
      "log"
      "os"
  
      "github.com/buckket/go-blurhash"
      "golang.org/x/image/tiff"
  )
  
  func main() {
      imageFile, err := os.Open("poc.tiff")
      if err != nil {
  	    log.Fatal(err)
      }
  
      loadedImage, err := tiff.Decode(imageFile)
      if err != nil {
  	    log.Fatal(err)
      }
  
      str, err := blurhash.Encode(4, 3, loadedImage) // Panic.
      if err != nil {
  	    log.Fatal(err)
      }
  
      fmt.Printf("Hash: %s\n", str)
  }

Panic

panic: runtime error: index out of range [70] with length 65

goroutine 1 [running]:
image.(*Paletted).At(0xc000061d68?, 0x48a050?, 0x101c000061d98?)
        /usr/local/go/src/image/image.go:1159 +0x9a
github.com/buckket/go-blurhash.multiplyBasisFunction({0x4dfb20, 0xc00002c2a0}, {0xc00014c000, 0x24, 0x1?}, 0x4, 0x3)
        .../poc-blurhash/vendor/github.com/buckket/go-blurhash/encode.go:131 +0x207
github.com/buckket/go-blurhash.Encode(0x4, 0x3, {0x4dfb20, 0xc00002c2a0})
        .../poc-blurhash/vendor/github.com/buckket/go-blurhash/encode.go:63 +0x22e
main.main()
        .../poc-blurhash/main.go:23 +0xc9
exit status 2

The official implementation with documentation and explanations is now live at https://github.com/woltapp/blurhash, in case you want to link to it!