package images import ( "fmt" "image" "github.com/nfnt/resize" "github.com/oliamb/cutter" "github.com/ethereum/go-ethereum/log" ) func Resize(size ResizeDimension, img image.Image) image.Image { var width, height uint switch { case img.Bounds().Max.X == img.Bounds().Max.Y: width, height = uint(size), uint(size) case img.Bounds().Max.X > img.Bounds().Max.Y: width, height = 0, uint(size) default: width, height = uint(size), 0 } log.Info("resizing", "size", size, "width", width, "height", height) return resize.Resize(width, height, img, resize.Bilinear) } func Crop(img image.Image, rect image.Rectangle) (image.Image, error) { if img.Bounds().Max.X < rect.Max.X || img.Bounds().Max.Y < rect.Max.Y { return nil, fmt.Errorf( "crop dimensions out of bounds of image, image width '%dpx' & height '%dpx'; crop bottom right coordinate at X '%dpx' Y '%dpx'", img.Bounds().Max.X, img.Bounds().Max.Y, rect.Max.X, rect.Max.Y, ) } return cutter.Crop(img, cutter.Config{ Width: rect.Dx(), Height: rect.Dy(), Anchor: rect.Min, }) } // CropImage takes an image, usually downloaded from a URL // If the image is square, the full image is returned // It the image is rectangular, the largest central square is returned // calculations at _docs/image-center-crop-calculations.png func CropCenter(img image.Image) (image.Image, error) { var cropRect image.Rectangle maxBounds := img.Bounds().Max if maxBounds.X == maxBounds.Y { return img, nil } if maxBounds.X > maxBounds.Y { // the final output should be YxY cropRect = image.Rectangle{ Min: image.Point{X: maxBounds.X/2 - maxBounds.Y/2, Y: 0}, Max: image.Point{X: maxBounds.X/2 + maxBounds.Y/2, Y: maxBounds.Y}, } } else { // the final output should be XxX cropRect = image.Rectangle{ Min: image.Point{X: 0, Y: maxBounds.Y/2 - maxBounds.X/2}, Max: image.Point{X: maxBounds.X, Y: maxBounds.Y/2 + maxBounds.X/2}, } } return Crop(img, cropRect) }