Added command line utility to test out the library interface

cmd/snapshot/main.go

@@ -0,0 +1,180 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"image"
+	"image/png"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/go-spatial/geom"
+	"github.com/go-spatial/geom/slippy"
+	mbgl "github.com/go-spatial/go-mbgl"
+)
+
+/*
+snapshotter bounds "lat long lat long" -width=100, -height=100 style filename.png
+snapshotter tile "z/x/y" style filename.png
+*/
+
+type cmdType uint8
+
+const (
+	CmdUnknown = cmdType(iota)
+	CmdBounds
+	CmdTile
+)
+
+func (c cmdType) String() string {
+	switch c {
+	case CmdBounds:
+		return "Bounds"
+	case CmdTile:
+		return "Tile"
+	default:
+		return "Unknown"
+	}
+}
+
+var FWidth uint
+var FHeight uint
+var FStyle string
+var FPixelRatio float64
+
+var FBounds geom.Extent
+var FTile slippy.Tile
+var FOutputFilename string
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "%v [options...] \"lat long lat long\" output_filename.png\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "%v [options...] bounds \"lat long lat long\" output_filename.png\n", os.Args[0])
+	fmt.Fprintf(os.Stderr, "%v [options...] tile \"z/x/y\" output_filename.png\n", os.Args[0])
+	flag.PrintDefaults()
+}
+
+func parseBounds(boundString string) {
+	var err error
+	bounds := strings.Split(boundString, " ")
+	if len(bounds) != 4 {
+		fmt.Fprintf(os.Stderr, "Error: invalid bounds provided — %v\n", boundString)
+		usage()
+		os.Exit(2)
+	}
+	for i, bound := range bounds {
+		FBounds[i], err = strconv.ParseFloat(strings.TrimSpace(bound), 64)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error: invalid bounds provided — %v\n", boundString)
+			fmt.Fprintf(os.Stderr, "Error: unabled to parse %v(%v) as a float.\n", bound, i)
+			usage()
+			os.Exit(2)
+		}
+	}
+}
+
+func parseTile(tileString string) {
+	var err error
+	var v uint64
+	parts := strings.Split(tileString, "/")
+	if len(parts) != 3 {
+		fmt.Fprintf(os.Stderr, "Error: invalid z/x/y coordinates  — %v\n", tileString)
+		usage()
+		os.Exit(2)
+	}
+	var label = [...]string{"Z", "X", "Y"}
+
+	for i, part := range parts {
+		v, err = strconv.ParseUint(strings.TrimSpace(part), 10, 64)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error: invalid tile coordinates provided — %v\n", tileString)
+			fmt.Fprintf(os.Stderr, "Error: unabled to parse %v %v as a uint.\n", label[i], part)
+			usage()
+			os.Exit(2)
+		}
+		switch i {
+		case 0:
+			FTile.Z = uint(v)
+		case 1:
+			FTile.X = uint(v)
+		case 2:
+			FTile.Y = uint(v)
+		}
+	}
+}
+
+func ParseFlags() cmdType {
+
+	flag.UintVar(&FWidth, "width", 100, "Width of the image to generate.")
+	flag.UintVar(&FWidth, "w", 100, "Width of the image to generate.")
+
+	flag.UintVar(&FHeight, "height", 100, "Height of the image to generate.")
+	flag.UintVar(&FHeight, "h", 100, "Height of the image to generate.")
+
+	flag.StringVar(&FStyle, "style", "https://osm.tegola.io/capabilities/osm.json", "Style file")
+	flag.Float64Var(&FPixelRatio, "pixel", 1.0, "The pixel ratio")
+
+	flag.Parse()
+
+	if flag.NArg() < 3 {
+		usage()
+		os.Exit(2)
+	}
+
+	var cmd cmdType
+	var fileIdx = 2
+
+	switch strings.TrimSpace(strings.ToLower(flag.Arg(0))) {
+	case "bounds":
+		// The next variable should be the bounds seperated by spaces.
+		parseBounds(flag.Arg(1))
+		cmd = CmdBounds
+	case "tile":
+		// The next variable should be the coordinates sepearted by forward slash.
+		parseTile(flag.Arg(1))
+
+		cmd = CmdTile
+	default: // assume bounds as the default subcommand
+		parseBounds(flag.Arg(0))
+		fileIdx = 1
+		cmd = CmdBounds
+	}
+
+	// Next should be the output filename.
+	FOutputFilename = strings.TrimSpace(flag.Arg(fileIdx))
+	return cmd
+
+}
+
+func main() {
+	var file *os.File
+	var err error
+	var img image.Image
+	cmd := ParseFlags()
+	file, err = os.Create(FOutputFilename)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error creating output file: %v\n", err)
+		os.Exit(3)
+	}
+	ss := mbgl.NewSnapshotter(FStyle, float32(FPixelRatio))
+	size := image.Point{
+		X: int(FWidth),
+		Y: int(FHeight),
+	}
+	switch cmd {
+	case CmdBounds:
+		img = ss.Snapshot(&FBounds, size)
+
+	case CmdTile:
+		img = mbgl.SnapshotTile(ss, FTile, size)
+
+	}
+	if err := png.Encode(file, img); err != nil {
+		file.Close()
+		log.Println("Failed to write %v", FOutputFilename)
+		log.Fatal(err)
+	}
+	file.Close()
+	fmt.Printf("successfully wrote outfile: %v\n", FOutputFilename)
+}

mbgl/camera_options.go

@@ -1,9 +1,8 @@
 package mbgl
-import "C"
 
 /*
 #include "camera_options.h"
- */
+*/
 import "C"
 
 type EdgeInsets C.MbglEdgeInsets
@@ -49,19 +48,21 @@ func (p *Point) update() {
 }
 
 func (p *Point) cPtr() *C.MbglPoint {
-	if p == nil {return nil}
+	if p == nil {
+		return nil
+	}
 
 	p.update()
 	return p.ptr
 }
 
 type CameraOptions struct {
-	Center *LatLng
+	Center  *LatLng
 	Padding *EdgeInsets
-	Anchor *Point
-	Zoom *float64
-	Angle *float64
-	Pitch *float64
+	Anchor  *Point
+	Zoom    *float64
+	Angle   *float64
+	Pitch   *float64
 
 	ptr *C.MbglCameraOptions
 }
@@ -101,7 +102,9 @@ func (opt *CameraOptions) update() {
 }
 
 func (opt *CameraOptions) cPtr() *C.MbglCameraOptions {
-	if opt == nil {return nil}
+	if opt == nil {
+		return nil
+	}
 
 	opt.update()
 	return opt.ptr

mbgl/mbgl.go

@@ -5,9 +5,12 @@ package mbgl
 #cgo CFLAGS: -D_GLIBCXX_USE_CXX11_ABI=1
 #cgo CXXFLAGS: -std=c++14 -std=gnu++14
 #cgo CXXFLAGS: -g
-#cgo CXXFLAGS: -I../mason_packages/.link/include
-#cgo LDFLAGS: -L../mason_packages/.link/lib
+#cgo CXXFLAGS: -I${SRCDIR}/../mason_packages/.link/include
+#cgo CXXFLAGS: -I${SRCDIR}/../mapbox-gl-native/include
+#cgo CXXFLAGS: -I${SRCDIR}/../mapbox-gl-native/platform/default
+#cgo LDFLAGS: -L${SRCDIR}/mason_packages/.link/lib
 #cgo LDFLAGS: -lsqlite3 -lz
 #cgo LDFLAGS: -lmbgl-filesource -lmbgl-core
- */
+
+*/
 import "C"