feat: Lazy-load fonts on demand instead of loading all fonts globally at once

captcha.go

@@ -50,7 +50,7 @@ func (c *Captcha) Generate() (id, b64s, answer string, err error) {
 // You may want to call `store.Verify` method instead.
 func (c *Captcha) Verify(id, answer string, clear bool) (match bool) {
 	vv := c.Store.Get(id, clear)
-    vv = strings.TrimSpace(vv)
-    answer = strings.TrimSpace(answer)
-    return strings.EqualFold(vv, answer)
+	vv = strings.TrimSpace(vv)
+	answer = strings.TrimSpace(answer)
+	return strings.EqualFold(vv, answer)
 }

driver_chinese.go

@@ -51,7 +51,7 @@ func NewDriverChinese(height int, width int, noiseCount int, showLineOptions int
 	}
 
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsAll()
 	}
 
 	return &DriverChinese{Height: height, Width: width, NoiseCount: noiseCount, ShowLineOptions: showLineOptions, Length: length, Source: source, BgColor: bgColor, fontsStorage: fontsStorage, fontsArray: tfs}
@@ -69,7 +69,7 @@ func (d *DriverChinese) ConvertFonts() *DriverChinese {
 		tfs = append(tfs, tf)
 	}
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsAll()
 	}
 	d.fontsArray = tfs
 

driver_language_test.go

@@ -9,7 +9,7 @@ import (
 )
 
 func TestDriverLanguage_DrawCaptcha(t *testing.T) {
-	ds := NewDriverLanguage(80, 240, 5, OptionShowSineLine|OptionShowSlimeLine|OptionShowHollowLine, 5, nil, nil, []*truetype.Font{fontChinese}, "emotion")
+	ds := NewDriverLanguage(80, 240, 5, OptionShowSineLine|OptionShowSlimeLine|OptionShowHollowLine, 5, nil, nil, []*truetype.Font{getFontChinese()}, "emotion")
 
 	for i := 0; i < 40; i++ {
 		_, q, _ := ds.GenerateIdQuestionAnswer()

driver_math.go

@@ -47,7 +47,7 @@ func NewDriverMath(height int, width int, noiseCount int, showLineOptions int, b
 	}
 
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsAll()
 	}
 
 	return &DriverMath{Height: height, Width: width, NoiseCount: noiseCount, ShowLineOptions: showLineOptions, fontsArray: tfs, BgColor: bgColor, Fonts: fonts}
@@ -65,7 +65,7 @@ func (d *DriverMath) ConvertFonts() *DriverMath {
 		tfs = append(tfs, tf)
 	}
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsAll()
 	}
 	d.fontsArray = tfs
 
@@ -118,7 +118,7 @@ func (d *DriverMath) DrawCaptcha(question string) (item Item, err error) {
 	//背景有文字干扰
 	if d.NoiseCount > 0 {
 		noise := RandText(d.NoiseCount, strings.Repeat(TxtNumbers, d.NoiseCount))
-		err = itemChar.drawNoise(noise, fontsAll)
+		err = itemChar.drawNoise(noise, d.fontsArray)
 		if err != nil {
 			return
 		}

driver_string.go

@@ -51,7 +51,7 @@ func NewDriverString(height int, width int, noiseCount int, showLineOptions int,
 	}
 
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsSimple()
 	}
 
 	return &DriverString{Height: height, Width: width, NoiseCount: noiseCount, ShowLineOptions: showLineOptions, Length: length, Source: source, BgColor: bgColor, fontsStorage: fontsStorage, fontsArray: tfs, Fonts: fonts}
@@ -69,7 +69,7 @@ func (d *DriverString) ConvertFonts() *DriverString {
 		tfs = append(tfs, tf)
 	}
 	if len(tfs) == 0 {
-		tfs = fontsAll
+		tfs = getFontsSimple()
 	}
 
 	d.fontsArray = tfs

driver_string_test.go

@@ -29,7 +29,7 @@ func TestDriverString_DrawCaptcha(t *testing.T) {
 		wantItem Item
 		wantErr  bool
 	}{
-		{"string", fields{80, 240, 20, 100, 2, 5, nil, fontsAll}, args{"45Ad8"}, nil, false},
+		{"string", fields{80, 240, 20, 100, 2, 5, nil, getFontsAll()}, args{"45Ad8"}, nil, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

fonts.go

@@ -2,34 +2,82 @@ package base64Captcha
 
 import (
 	"math/rand"
+	"sync"
 
 	"github.com/golang/freetype/truetype"
 )
 
-var fontsSimple = DefaultEmbeddedFonts.LoadFontsByNames([]string{
-	"fonts/3Dumb.ttf",
-	"fonts/ApothecaryFont.ttf",
-	"fonts/Comismsh.ttf",
-	"fonts/DENNEthree-dee.ttf",
-	"fonts/DeborahFancyDress.ttf",
-	"fonts/Flim-Flam.ttf",
-	"fonts/RitaSmith.ttf",
-	"fonts/actionj.ttf",
-	"fonts/chromohv.ttf",
-})
+// Available fonts
+const (
+	Font3Dumb             = "3Dumb.ttf"
+	FontApothecaryFont    = "ApothecaryFont.ttf"
+	FontComismsh          = "Comismsh.ttf"
+	FontDENNEthreeDee     = "DENNEthree-dee.ttf"
+	FontDeborahFancyDress = "DeborahFancyDress.ttf"
+	FontFlimFlam          = "Flim-Flam.ttf"
+	FontRitaSmith         = "RitaSmith.ttf"
+	FontActionj           = "actionj.ttf"
+	FontChromohv          = "chromohv.ttf"
+	FontWqyMicrohei       = "wqy-microhei.ttc"
+)
+
+const FontPrefix = "fonts/"
 
-// var fontemoji = loadFontByName("fonts/seguiemj.ttf")
-var fontsAll = append(fontsSimple, fontChinese)
-var fontChinese = DefaultEmbeddedFonts.LoadFontByName("fonts/wqy-microhei.ttc")
+// Private variables for lazy loading
+var (
+	fontsSimple     []*truetype.Font
+	fontChinese     *truetype.Font
+	fontsAll        []*truetype.Font
+	fontsSimpleOnce sync.Once
+	fontChineseOnce sync.Once
+	fontsAllOnce    sync.Once
+)
+
+// getFontsSimple returns the simple font collection (without Chinese fonts).
+// Fonts are loaded lazily on first call.
+func getFontsSimple() []*truetype.Font {
+	fontsSimpleOnce.Do(func() {
+		fontsSimple = DefaultEmbeddedFonts.LoadFontsByNames([]string{
+			FontPrefix + Font3Dumb,
+			FontPrefix + FontApothecaryFont,
+			FontPrefix + FontComismsh,
+			FontPrefix + FontDENNEthreeDee,
+			FontPrefix + FontDeborahFancyDress,
+			FontPrefix + FontFlimFlam,
+			FontPrefix + FontRitaSmith,
+			FontPrefix + FontActionj,
+			FontPrefix + FontChromohv,
+		})
+	})
+	return fontsSimple
+}
+
+// getFontChinese returns the Chinese font.
+// Font is loaded lazily on first call.
+func getFontChinese() *truetype.Font {
+	fontChineseOnce.Do(func() {
+		fontChinese = DefaultEmbeddedFonts.LoadFontByName(FontPrefix + FontWqyMicrohei)
+	})
+	return fontChinese
+}
+
+// getFontsAll returns all fonts (simple fonts + Chinese font).
+// Fonts are loaded lazily on first call.
+func getFontsAll() []*truetype.Font {
+	fontsAllOnce.Do(func() {
+		fontsAll = append(getFontsSimple(), getFontChinese())
+	})
+	return fontsAll
+}
 
 // randFontFrom choose random font family.选择随机的字体
 func randFontFrom(fonts []*truetype.Font) *truetype.Font {
 	fontCount := len(fonts)
 
 	if fontCount == 0 {
 		//loading default fonts
-		fonts = fontsAll
-		fontCount = len(fontsAll)
+		fonts = getFontsAll()
+		fontCount = len(fonts)
 	}
 	index := rand.Intn(fontCount)
 	return fonts[index]

fonts_test.go

@@ -45,7 +45,7 @@ func Test_loadFontsByNames(t *testing.T) {
 }
 
 func Test_randFontFrom(t *testing.T) {
-	f := randFontFrom(fontsAll)
+	f := randFontFrom(getFontsAll())
 	if f == nil {
 		t.Error("failed")
 	}

store_sync_map.go

@@ -61,5 +61,5 @@ func (s StoreSyncMap) Get(id string, clear bool) string {
 // Verify check a string value
 func (s StoreSyncMap) Verify(id, answer string, clear bool) bool {
 	vv := s.Get(id, clear)
-    return strings.EqualFold(vv, answer)
+	return strings.EqualFold(vv, answer)
 }