hide ttfFont from globalvars, remove Init func

Signed-off-by: s3rj1k <evasive.gyron@gmail.com>

captcha.go

@@ -22,10 +22,6 @@ import (
 
 const charPreset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
 
-var (
-	ttfFont *truetype.Font
-)
-
 // Options manage captcha generation details.
 type Options struct {
 	// BackgroundColor is captcha image's background color.
@@ -53,6 +49,8 @@ type Options struct {
 	Noise float64
 	// Palette is the set of colors to chose from
 	Palette color.Palette
+	// TTFFont defines font to use for captcha text.
+	TTFFont *truetype.Font
 
 	width  int
 	height int
@@ -79,6 +77,8 @@ func newDefaultOption(width, height int) *Options {
 				time.Now().UnixNano(),
 			),
 		),
+
+		TTFFont: MustLoadFont(ttf),
 	}
 }
 
@@ -113,23 +113,27 @@ func (data *Data) WriteGIF(w io.Writer, o *gif.Options) error {
 	return gif.Encode(w, data.img, o)
 }
 
-// nolint: gochecknoinits
-func init() {
-	ttfFont, _ = freetype.ParseFont(ttf)
+// LoadFont let you load an external font.
+func LoadFont(fontData []byte) (*truetype.Font, error) {
+	return freetype.ParseFont(fontData)
 }
 
-// LoadFont let you load an external font.
-func LoadFont(fontData []byte) error {
-	var err error
-	ttfFont, err = freetype.ParseFont(fontData)
-	return err
+// MustLoadFont let you load an external font.
+// Function assumes that font is valid.
+func MustLoadFont(fontData []byte) *truetype.Font {
+	ttfFont, err := LoadFont(fontData)
+	if err != nil {
+		return nil
+	}
+
+	return ttfFont
 }
 
 // LoadFontFromReader load an external font from an io.Reader interface.
-func LoadFontFromReader(reader io.Reader) error {
+func LoadFontFromReader(reader io.Reader) (*truetype.Font, error) {
 	var buf bytes.Buffer
 	if _, err := io.Copy(&buf, reader); err != nil {
-		return err
+		return nil, err
 	}
 
 	return LoadFont(buf.Bytes())
@@ -240,7 +244,7 @@ func drawText(text string, img *image.NRGBA, opts *Options) error { // nolint: i
 	ctx.SetClip(img.Bounds())
 	ctx.SetDst(img)
 	ctx.SetHinting(font.HintingFull)
-	ctx.SetFont(ttfFont)
+	ctx.SetFont(opts.TTFFont)
 
 	fontSpacing := opts.width / len(text)
 	fontOffset := opts.rng.Intn(fontSpacing / 2)

captcha_test.go

@@ -87,21 +87,10 @@ func TestNewMathExpr(t *testing.T) {
 	}
 }
 
-func TestCovNilFontError(t *testing.T) {
-	temp := ttfFont
-	ttfFont = nil
-
-	_, err := New(150, 50)
-	if err == nil {
-		t.Fatal("Expect to get nil font error")
+func TestCovInternalFontErr(t *testing.T) {
+	if ttfFont := MustLoadFont(ttf); ttfFont == nil {
+		t.Fatal("Fail to load internal font")
 	}
-
-	_, err = NewMathExpr(150, 50)
-	if err == nil {
-		t.Fatal("Expect to get nil font error")
-	}
-
-	ttfFont = temp
 }
 
 type errReader struct{}
@@ -111,20 +100,18 @@ func (errReader) Read(_ []byte) (int, error) {
 }
 
 func TestCovReaderErr(t *testing.T) {
-	err := LoadFontFromReader(errReader{})
+	_, err := LoadFontFromReader(errReader{})
 	if err == nil {
 		t.Fatal("Expect to get io.Reader error")
 	}
 }
 
 func TestLoadFont(t *testing.T) {
-	err := LoadFont(goregular.TTF)
-	if err != nil {
+	if _, err := LoadFont(goregular.TTF); err != nil {
 		t.Fatal("Fail to load go font")
 	}
 
-	err = LoadFont([]byte("invalid"))
-	if err == nil {
+	if _, err := LoadFont([]byte("invalid")); err == nil {
 		t.Fatal("LoadFont incorrectly parse an invalid font")
 	}
 }
@@ -135,7 +122,7 @@ func TestLoadFontFromReader(t *testing.T) {
 		t.Fatal("Fail to load test file")
 	}
 
-	if err = LoadFontFromReader(file); err != nil {
+	if _, err := LoadFontFromReader(file); err != nil {
 		t.Fatal("Fail to load font from io.Reader")
 	}
 }

example/load-font/main.go

@@ -7,10 +7,15 @@ import (
 
 	"github.com/steambap/captcha"
 	"golang.org/x/image/font/gofont/goregular"
+	"github.com/golang/freetype/truetype"
 )
 
+var ttf *truetype.Font
+
 func main() {
-	err := captcha.LoadFont(goregular.TTF)
+	var err error
+
+	ttf, err = captcha.LoadFont(goregular.TTF)
 	if err != nil {
 		panic(err)
 	}
@@ -44,6 +49,7 @@ func indexHandle(w http.ResponseWriter, _ *http.Request) {
 func captchaHandle(w http.ResponseWriter, _ *http.Request) {
 	img, err := captcha.New(150, 50, func(options *captcha.Options) {
 		options.FontScale = 0.8
+		options.TTFFont = ttf
 	})
 	if err != nil {
 		fmt.Fprint(w, nil)