magick-fun.go

package main

import (
	"bytes"
	"fmt"
	"github.com/codegangsta/martini"
	"github.com/rainycape/magick"
	"io/ioutil"
	"log"
	"net/http"
	"runtime"
	"time"
)

func main() {
	runtime.GOMAXPROCS(runtime.NumCPU())
	fmt.Printf("GOMAXPROCS is %d\n", runtime.GOMAXPROCS(0))

	// Grab the sample image
	url := "http://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Ferrari_F430_front_20080605.jpg/1600px-Ferrari_F430_front_20080605.jpg"
	resp, err := http.Get(url)
	if err != nil {
		log.Panic(err)
	}
	defer resp.Body.Close()
	img, _ := ioutil.ReadAll(resp.Body)

	//--

	m := martini.New()
	m.Use(martini.Logger())
	m.Use(martini.Recovery())

	r := martini.NewRouter()
	m.Action(r.Handle)

	r.Get("/", func(res http.ResponseWriter, req *http.Request) {
		img2 := resizeImgInHalf(img)
		res.WriteHeader(200)
		res.Write(img2)
	})

	if err := http.ListenAndServe(":4000", m); err != nil {
		log.Fatal(err)
	}
}

func resizeImgInHalf(img []byte) []byte {
	start := time.Now()

	im, err := magick.DecodeData(img)
	if err != nil {
		log.Panicln(err)
		return nil
	}
	defer im.Dispose()

	w := int(im.Width() / 2)
	h := int(im.Height() / 2)

	im2, err := im.Resize(w, h, magick.FQuadratic)
	if err != nil {
		log.Panicln(err)
		return nil
	}

	buf := &bytes.Buffer{}
	err = im2.Encode(buf, nil)
	if err != nil {
		log.Panicln(err)
		return nil
	}

	elapsed := time.Since(start)
	log.Printf("Took %s", elapsed)

	return buf.Bytes()
}