diff options
| -rw-r--r-- | main.go | 129 |
1 files changed, 129 insertions, 0 deletions
@@ -0,0 +1,129 @@ +package main + +import ( + "encoding/json" + "fmt" + "image" + "image/draw" + "image/png" + "io/ioutil" + "log" + "net/http" + "os" + "os/exec" + "time" +) + +var level = 4 +var width = 550 +var delay = 8 // delay in hours, so that I can see daylight on my wallpaper during the day! + +type latestData struct { + Date string `json:"date"` + File string `json:"file"` +} + +func main() { + // Define work directory and files + var home = os.Getenv("HOME") + var work_dir = home + "/.himawari" + var image_file = work_dir + "/latest.png" + var dat_file = work_dir + "/data" + + // Read the last date from dat_file if it exists + data, err := ioutil.ReadFile(dat_file) + oldData := new(latestData) + if err != nil { + data = nil + } else { + err = json.Unmarshal(data, oldData) + if err != nil { + oldData = nil + } + } + + // Get the data about the last image + initData := new(latestData) + err = getJson("http://himawari8-dl.nict.go.jp/himawari8/img/D531106/latest.json", initData) + if err != nil { + log.Fatal("error getting json :", err) + } + + location, _ := time.LoadLocation("Asia/Tokyo") + t, _ := time.ParseInLocation("2006-01-02 15:04:05", initData.Date, location) + if oldData != nil && oldData.Date == initData.Date { + log.Print("No new image, keeping the old one") + os.Exit(0) + } + t = t.Add(time.Duration(-delay) * time.Hour) + + // Get all the chunks from the latest image and assemble them + output := image.NewRGBA(image.Rect(0, 0, level*width, level*width)) + for x := 0; x < level; x++ { + for y := 0; y < level; y++ { + url := fmt.Sprintf("http://himawari8.nict.go.jp/img/D531106/%dd/%d/%s_%d_%d.png", + level, width, t.Format("2006/01/02/150405"), x, y) + + var buff image.Image + err = getPng(url, &buff) + if err != nil { + err = getPng(url, &buff) + if err != nil { + log.Fatal("Error getting png :", url) + } + } + + draw.Draw(output, image.Rect(x*width, y*width, (x+1)*width, (y+1)*width), buff, image.Point{0, 0}, draw.Src) + } + } + + // Write output to file + out, err := os.Create(image_file) + if err != nil { + err := os.Mkdir(work_dir, 0755) + if err != nil { + log.Fatal("error creating :", err) + } + out, err = os.Create(image_file) + if err != nil { + log.Fatal("error creating :", err) + } + } + defer out.Close() + err = png.Encode(out, output) + if err != nil { + log.Fatal("Error writing output:", err) + } + + // Write dat file + buff, err := json.Marshal(initData) + ioutil.WriteFile(dat_file, buff, 0644) + + // Exec feh + cmd := exec.Command("feh", "--bg-max", image_file) + err = cmd.Run() + if err != nil { + log.Fatal("Error launching feh :", err) + } +} + +func getJson(url string, target interface{}) error { + r, err := http.Get(url) + if err != nil { + return err + } + defer r.Body.Close() + + return json.NewDecoder(r.Body).Decode(target) +} + +func getPng(url string, image *image.Image) error { + r, err := http.Get(url) + if err != nil { + return err + } + defer r.Body.Close() + + *image, err = png.Decode(r.Body) + return err +} |