diff options
Diffstat (limited to 'map.go')
-rw-r--r-- | map.go | 88 |
1 files changed, 0 insertions, 88 deletions
@@ -1,88 +0,0 @@ -/* -Copyright © 2020 Alexander Kiryukhin <ak@bytechain.ru> -This file is part of OsmStatic project. -*/ -package main - -import ( - "bytes" - "fmt" - "image" - "image/color" - "image/png" - _ "image/png" - "io/ioutil" - "log" - "math" - "net/http" - "sync" - - "github.com/disintegration/imaging" -) - -const ( - tileAddr = `https://a.tile.openstreetmap.org/%d/%d/%d.png` - tw = 256 - th = 256 -) - -func GetMapImage(lat, lon float64, zoom, width, height int) ([]byte, error) { - x, y, dx, dy := getCoords(lat, lon, zoom) - dst := imaging.New(width, height, color.NRGBA{0, 255, 0, 255}) - wg := sync.WaitGroup{} - mu := sync.Mutex{} - cx := width/2 - tw/2 - cy := height/2 - th/2 - sx := width/tw + 2 - sy := height/th + 2 - di := int(dx*float64(tw)) - tw/2 - dj := int(dy*float64(th)) - th/2 - for i := -sx / 2; i <= sx/2; i++ { - for j := -sy / 2; j <= sy/2; j++ { - wg.Add(1) - go func(i, j int) { - defer wg.Done() - tile, err := getTile(x+i, y+j, zoom) - if err != nil { - log.Println(err) - return - } - img, err := png.Decode(bytes.NewReader(tile)) - if err != nil { - log.Println(err) - return - } - mu.Lock() - defer mu.Unlock() - tx := cx + i*tw - di - ty := cy + j*th - dj - dst = imaging.Paste(dst, img, image.Pt(tx, ty)) - }(int(i), int(j)) - } - } - wg.Wait() - - out := bytes.NewBuffer([]byte{}) - if err := imaging.Encode(out, dst, imaging.PNG); err != nil { - return nil, err - } - return out.Bytes(), nil -} - -func getCoords(lat, lon float64, zoom int) (int, int, float64, float64) { - x := (lon + 180.0) / 360.0 * (math.Exp2(float64(zoom))) - y := (1.0 - math.Log(math.Tan(lat*math.Pi/180.0)+1.0/math.Cos(lat*math.Pi/180.0))/math.Pi) / 2.0 * (math.Exp2(float64(zoom))) - dx := x - math.Floor(x) - dy := y - math.Floor(y) - return int(math.Floor(x)), int(math.Floor(y)), dx, dy -} - -func getTile(x, y, z int) ([]byte, error) { - tile := fmt.Sprintf(tileAddr, z, x, y) - resp, err := http.DefaultClient.Get(tile) - if err != nil { - return nil, err - } - defer resp.Body.Close() - return ioutil.ReadAll(resp.Body) -} |