hackkrk 4/2013 image upload

hackkrk.go

package main

import (
  "encoding/json"
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"io/ioutil"
	"log"
	"math/rand"
	"net/http"
	"os"
	"time"
)

const (
	GET_COLOR_URL = "http://localhost:12345/get-color"
)

type Response struct {
	Id    int
	Color []interface{}
}

func main() {
	rand.Seed(time.Now().UTC().UnixNano())
	file, err := os.Open("img.png")
	if err != nil {
		log.Fatal(err)
	}

	img, _, err := image.Decode(file)
	file.Close()

	for {
		handle_request(img)
	}
}

func handle_request(img image.Image) {
	resp, err := http.Get(GET_COLOR_URL)
	resp_body, err := ioutil.ReadAll(resp.Body)
	resp.Body.Close()

	if err != nil {
		log.Fatal(err)
	}

	// unmarshall response
	var resp_json Response
	err = json.Unmarshal(resp_body, &resp_json)
	rgba := getColor(resp_json.Color)

	// draw image
	rect := image.Rect(0, 0, 64, 64)
	dest := image.NewRGBA(rect)
	draw.Draw(dest, dest.Bounds(), &image.Uniform{rgba}, image.ZP, draw.Src)
	draw.Draw(dest, rect, img, rect.Min, draw.Over)

	// out := &bytes.Buffer{}
	filename := fmt.Sprintf("out/%d.png", time.Now().UTC().UnixNano())
	out, err := os.Create(filename)
	if err != nil {
		log.Fatal(err)
	}

	err = png.Encode(out, dest)

	if err == nil {
		fmt.Printf("saved %s\n", filename)
	}
}

func getColor(color_data []interface{}) color.RGBA {
	var rgb [3]uint8

	if len(color_data) > 3 {
		log.Fatal("InvalidColor")
	}

	for i := 0; i < 3; i++ {
		switch color_data[i].(type) {
		default:
			log.Fatal("InvalidColor")
		case float64:
			rgb[i] = uint8(color_data[i].(float64))
		}
	}

	return color.RGBA{rgb[0], rgb[1], rgb[2], 255}
}