smartcrop finds good image crops for arbitrary sizes. It is a pure Go implementation, based on Jonas Wagner's smartcrop.js

Image: https://www.flickr.com/photos/usfwspacific/8182486789 by Washington Dept of Fish and Wildlife, originally licensed under CC-BY-2.0 when the image was imported back in September 2014

Image: https://www.flickr.com/photos/endogamia/5682480447 by Leon F. Cabeiro (N. Feans), licensed under CC-BY-2.0

Make sure you have a working Go environment (Go 1.12 or higher is required). See the install instructions.

To install smartcrop, simply run:

go get github.com/muesli/smartcrop

To compile it from source:

git clone https://github.com/muesli/smartcrop.git
cd smartcrop
go build

package main
import (
	"fmt"
	"image"
	_ "image/png"
	"os"
	"github.com/muesli/smartcrop"
	"github.com/muesli/smartcrop/nfnt"
)
func main() {
	f, _ := os.Open("image.png")
	img, _, _ := image.Decode(f)
	analyzer := smartcrop.NewAnalyzer(nfnt.NewDefaultResizer())
	topCrop, _ := analyzer.FindBestCrop(img, 250, 250)
	// The crop will have the requested aspect ratio, but you need to copy/scale it yourself
	fmt.Printf("Top crop: %+v\n", topCrop)
	type SubImager interface {
		SubImage(r image.Rectangle) image.Image
	}
	croppedimg := img.(SubImager).SubImage(topCrop)
	// ...
}

Also see the test cases in smartcrop_test.go and cli application in cmd/smartcrop/ for further working examples.

go install github.com/muesli/smartcrop/cmd/smartcrop
Usage of smartcrop:
  -height int
        crop height
  -input string
        input filename
  -output string
        output filename
  -quality int
        jpeg quality (default 85)
  -resize
        resize after cropping (default true)
  -width int
        crop width

Example: smartcrop -input examples/gopher.jpg -output gopher_cropped.jpg -width 300 -height 150

You can find a bunch of test images for the algorithm here.

Got some feedback or suggestions? Please open an issue or drop me a note!

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