Render transparent tiles if command line flag is set.

cmd/mtwebmapper/main.go

@@ -17,14 +17,15 @@ import (
 
 func main() {
 	var (
-		webPort    int
-		webHost    string
-		webDir     string
-		mapDir     string
-		redisPort  int
-		redisHost  string
-		colorsFile string
-		workers    int
+		webPort     int
+		webHost     string
+		webDir      string
+		mapDir      string
+		redisPort   int
+		redisHost   string
+		colorsFile  string
+		workers     int
+		transparent bool
 	)
 	flag.IntVar(&webPort, "web-port", 8808, "port of the web server")
 	flag.IntVar(&webPort, "p", 8808, "port of the web server (shorthand)")
@@ -41,6 +42,8 @@ func main() {
 	flag.IntVar(&workers, "workers", 1, "number of workers to render tiles")
 	flag.StringVar(&colorsFile, "colors", "colors.txt", "colors used to render map tiles.")
 	flag.StringVar(&colorsFile, "c", "colors.txt", "colors used to render map tiles (shorthand).")
+	flag.BoolVar(&transparent, "transparent", false, "Render transparent blocks.")
+	flag.BoolVar(&transparent, "t", false, "Render transparent blocks (shorthand).")
 
 	flag.Parse()
 
@@ -56,7 +59,7 @@ func main() {
 			log.Fatalf("ERROR: problem loading colors: %s", err)
 		}
 		redisAddress := fmt.Sprintf("%s:%d", redisHost, redisPort)
-		tu := newTileUpdater(mapDir, redisAddress, colors, workers)
+		tu := newTileUpdater(mapDir, redisAddress, colors, transparent, workers)
 		go tu.doUpdates()
 		router.Path("/update").Methods("POST").Handler(tu)
 	}

cmd/mtwebmapper/tilesupdater.go

@@ -26,6 +26,7 @@ type tileUpdater struct {
 	redisAddress string
 	colors       *common.Colors
 	workers      int
+	transparent  bool
 	cond         *sync.Cond
 	mu           sync.Mutex
 }
@@ -56,12 +57,18 @@ func (c xz) parent() xzm {
 		Mask: 1 << (zr<<1 | xr)}
 }
 
-func newTileUpdater(mapDir, redisAddress string, colors *common.Colors, workers int) *tileUpdater {
+func newTileUpdater(
+	mapDir, redisAddress string,
+	colors *common.Colors,
+	transparent bool,
+	workers int) *tileUpdater {
+
 	tu := tileUpdater{
 		mapDir:       mapDir,
 		redisAddress: redisAddress,
 		changes:      map[xz]bool{},
 		colors:       colors,
+		transparent:  transparent,
 		workers:      workers}
 	tu.cond = sync.NewCond(&tu.mu)
 	return &tu
@@ -113,7 +120,7 @@ func (tu *tileUpdater) doUpdates() {
 				log.Printf("WARN: Cannot connect to redis server: %s", err)
 				continue
 			}
-			btc := common.NewBaseTileCreator(client, tu.colors, baseDir, true)
+			btc := common.NewBaseTileCreator(client, tu.colors, tu.transparent, baseDir, true)
 			done.Add(1)
 			go updateBaseTiles(jobs, btc, &done)
 		}