simplified command line parsing

README.md

@@ -91,7 +91,7 @@ The `--marker` option defines one or more map markers of the same style. Use mul
 `MARKER_STYLES` consists of a set of style descriptors separated by the pipe character `|`:
 
 - `color:COLOR` - where `COLOR` is either of the form `0xRRGGBB`, `0xRRGGBBAA`, or one of `black`, `blue`, `brown`, `green`, `orange`, `purple`, `red`, `yellow`, `white` (default: `red`)
-- `size:SIZE` - where `SIZE` is one of `mid`, `small`, `tiny` (default: `mid`)
+- `size:SIZE` - where `SIZE` is one of `mid`, `small`, `tiny`, or some number > 0 (default: `mid`)
 - `label:LABEL` - where `LABEL` is an alpha numeric character, i.e. `A`-`Z`, `a`-`z`, `0`-`9`; (default: no label)
 
 ### Paths

area.go

@@ -32,21 +32,21 @@ func ParseAreaString(s string) (*Area, error) {
 	area.Weight = 5.0
 
 	for _, ss := range strings.Split(s, "|") {
-		if strings.HasPrefix(ss, "color:") {
+		if ok, suffix := hasPrefix(ss, "color:"); ok {
 			var err error
-			area.Color, err = ParseColorString(strings.TrimPrefix(ss, "color:"))
+			area.Color, err = ParseColorString(suffix)
 			if err != nil {
 				return nil, err
 			}
-		} else if strings.HasPrefix(ss, "fill:") {
+		} else if ok, suffix := hasPrefix(ss, "fill:"); ok {
 			var err error
-			area.Fill, err = ParseColorString(strings.TrimPrefix(ss, "fill:"))
+			area.Fill, err = ParseColorString(suffix)
 			if err != nil {
 				return nil, err
 			}
-		} else if strings.HasPrefix(ss, "weight:") {
+		} else if ok, suffix := hasPrefix(ss, "weight:"); ok {
 			var err error
-			area.Weight, err = strconv.ParseFloat(strings.TrimPrefix(ss, "weight:"), 64)
+			area.Weight, err = strconv.ParseFloat(suffix, 64)
 			if err != nil {
 				return nil, err
 			}
@@ -80,15 +80,12 @@ func (p *Area) draw(gc *gg.Context, trans *transformer) {
 	}
 
 	gc.ClearPath()
-
 	gc.SetLineWidth(p.Weight)
 	gc.SetLineCap(gg.LineCapRound)
 	gc.SetLineJoin(gg.LineJoinRound)
-
 	for _, ll := range p.Positions {
 		gc.LineTo(trans.ll2p(ll))
 	}
-
 	gc.ClosePath()
 	gc.SetColor(p.Fill)
 	gc.FillPreserve()

marker.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"image/color"
 	"math"
+	"strconv"
 	"strings"
 
 	"github.com/flopp/go-coordsparser"
@@ -36,14 +37,19 @@ func NewMarker(pos s2.LatLng, col color.Color, size float64) *Marker {
 }
 
 func parseSizeString(s string) (float64, error) {
-	if s == "mid" {
+	switch {
+	case s == "mid":
 		return 16.0, nil
-	} else if s == "small" {
+	case s == "small":
 		return 12.0, nil
-	} else if s == "tiny" {
+	case s == "tiny":
 		return 8.0, nil
 	}
 
+	if ss, err := strconv.ParseFloat(s, 64); err != nil && ss > 0 {
+		return ss, nil
+	}
+
 	return 0.0, fmt.Errorf("Cannot parse size string: %s", s)
 }
 
@@ -56,17 +62,17 @@ func ParseMarkerString(s string) ([]*Marker, error) {
 	label := ""
 
 	for _, ss := range strings.Split(s, "|") {
-		if strings.HasPrefix(ss, "color:") {
+		if ok, suffix := hasPrefix(ss, "color:"); ok {
 			var err error
-			color, err = ParseColorString(strings.TrimPrefix(ss, "color:"))
+			color, err = ParseColorString(suffix)
 			if err != nil {
 				return nil, err
 			}
-		} else if strings.HasPrefix(ss, "label:") {
-			label = strings.TrimPrefix(ss, "label:")
-		} else if strings.HasPrefix(ss, "size:") {
+		} else if ok, suffix := hasPrefix(ss, "label:"); ok {
+			label = suffix
+		} else if ok, suffix := hasPrefix(ss, "size:"); ok {
 			var err error
-			size, err = parseSizeString(strings.TrimPrefix(ss, "size:"))
+			size, err = parseSizeString(suffix)
 			if err != nil {
 				return nil, err
 			}
@@ -95,7 +101,6 @@ func (m *Marker) bounds() s2.Rect {
 
 func (m *Marker) draw(gc *gg.Context, trans *transformer) {
 	gc.ClearPath()
-
 	gc.SetLineJoin(gg.LineJoinRound)
 	gc.SetLineWidth(1.0)
 

path.go

@@ -30,15 +30,15 @@ func ParsePathString(s string) (*Path, error) {
 	path.Weight = 5.0
 
 	for _, ss := range strings.Split(s, "|") {
-		if strings.HasPrefix(ss, "color:") {
+		if ok, suffix := hasPrefix(ss, "color:"); ok {
 			var err error
-			path.Color, err = ParseColorString(strings.TrimPrefix(ss, "color:"))
+			path.Color, err = ParseColorString(suffix)
 			if err != nil {
 				return nil, err
 			}
-		} else if strings.HasPrefix(ss, "weight:") {
+		} else if ok, suffix := hasPrefix(ss, "weight:"); ok {
 			var err error
-			path.Weight, err = strconv.ParseFloat(strings.TrimPrefix(ss, "weight:"), 64)
+			path.Weight, err = strconv.ParseFloat(suffix, 64)
 			if err != nil {
 				return nil, err
 			}
@@ -72,15 +72,12 @@ func (p *Path) draw(gc *gg.Context, trans *transformer) {
 	}
 
 	gc.ClearPath()
-
 	gc.SetLineWidth(p.Weight)
 	gc.SetLineCap(gg.LineCapRound)
 	gc.SetLineJoin(gg.LineJoinRound)
-
 	for _, ll := range p.Positions {
 		gc.LineTo(trans.ll2p(ll))
 	}
-
 	gc.SetColor(p.Color)
 	gc.Stroke()
 }

tile_fetcher.go

@@ -13,6 +13,7 @@ import (
 	_ "image/png"  // to be able to decode pngs
 	"io"
 	"io/ioutil"
+	"log"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -78,9 +79,8 @@ func (t *TileFetcher) Fetch(zoom, x, y int) (image.Image, error) {
 
 	if t.useCaching {
 		fileName := t.cacheFileName(zoom, x, y)
-		if err = t.storeCache(fileName, data); err != nil {
-			fmt.Println("Failed to store image as", fileName)
-			fmt.Println(err)
+		if err := t.storeCache(fileName, data); err != nil {
+			log.Printf("Failed to store map tile as '%s': %s", fileName, err)
 		}
 	}
 

util.go

@@ -0,0 +1,18 @@
+// Copyright 2016 Florian Pigorsch. All rights reserved.
+//
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package sm
+
+import (
+	"strings"
+)
+
+// hasPrefix checks if 's' has prefix 'prefix'; returns 'true' and the remainder on success, and 'false', 's' otherwise.
+func hasPrefix(s string, prefix string) (bool, string) {
+	if strings.HasPrefix(s, prefix) {
+		return true, strings.TrimPrefix(s, prefix)
+	}
+	return false, s
+}