refactor: split utils.go

Author: fumiama

color.go

@@ -26,8 +26,10 @@ var (
 	Opaque  = color.RGBA{0, 0, 0, 0}
 )
 
-// takeThemeColorsKMeans 实现基于k-means算法的图像取色算法
-func takeThemeColorsKMeans(img image.Image, k int) []color.RGBA {
+// TakeThemeColorsKMeans extracts the k dominant colors from an image using k-means.
+//
+// TakeThemeColorsKMeans 使用 k-means 算法从图像中提取 k 个主色。
+func TakeThemeColorsKMeans(img image.Image, k int) []color.RGBA {
 	rgbaimg := ImageToRGBA(img)
 	pixels := unsafe.Slice(
 		(*color.RGBA)(unsafe.Pointer(unsafe.SliceData(rgbaimg.Pix))),
@@ -57,11 +59,11 @@ func takeThemeColorsKMeans(img image.Image, k int) []color.RGBA {
 
 		// 计算每个聚类的新中心
 		newClusters := make([]color.RGBA, k)
-		for i := range k {
+		for currentCluster := range k {
 			var r, g, b uint32
 			n := 0
-			for j, cluster := range clusterAssignments {
-				if cluster == i {
+			for j, pixelCluster := range clusterAssignments {
+				if pixelCluster == currentCluster {
 					pixel := pixels[j]
 					r += uint32(pixel.R)
 					g += uint32(pixel.G)
@@ -70,12 +72,12 @@ func takeThemeColorsKMeans(img image.Image, k int) []color.RGBA {
 				}
 			}
 			if n != 0 {
-				newClusters[i] = color.RGBA{uint8(r / uint32(n)), uint8(g / uint32(n)), uint8(b / uint32(n)), 255}
+				newClusters[currentCluster] = color.RGBA{uint8(r / uint32(n)), uint8(g / uint32(n)), uint8(b / uint32(n)), 255}
 			}
 		}
 
 		// 如果聚类中心没有变化，则停止迭代
-		if clustersEqual(clusters, newClusters) {
+		if isArrayRGBAEqual(clusters, newClusters) {
 			break
 		}
 		clusters = newClusters
@@ -84,6 +86,35 @@ func takeThemeColorsKMeans(img image.Image, k int) []color.RGBA {
 	return clusters
 }
 
+// isArrayRGBAEqual compares two []color.RGBA is equal fastly.
+//
+// isArrayRGBAEqual 快速比较两个 []color.RGBA 是否相等。
+func isArrayRGBAEqual(a, b []color.RGBA) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	sz := len(a)
+	if sz%2 == 0 { // can compare by uint64
+		u64a := unsafe.Slice((*uint64)(unsafe.Pointer(unsafe.SliceData(a))), sz/2)
+		u64b := unsafe.Slice((*uint64)(unsafe.Pointer(unsafe.SliceData(b))), sz/2)
+		for i := range u64a {
+			if u64a[i] != u64b[i] {
+				return false
+			}
+		}
+		return true
+	}
+	// compare by uint32
+	u32a := unsafe.Slice((*uint32)(unsafe.Pointer(unsafe.SliceData(a))), sz)
+	u32b := unsafe.Slice((*uint32)(unsafe.Pointer(unsafe.SliceData(b))), sz)
+	for i := range u32a {
+		if u32a[i] != u32b[i] {
+			return false
+		}
+	}
+	return true
+}
+
 // 计算两个颜色之间的距离
 func distance(a, b color.RGBA) float64 {
 	return math.Sqrt(sq(float64(a.R)-float64(b.R)) + sq(float64(a.G)-float64(b.G)) + sq(float64(a.B)-float64(b.B)))
@@ -93,16 +124,3 @@ func distance(a, b color.RGBA) float64 {
 func sq(n float64) float64 {
 	return n * n
 }
-
-// 比较两个聚类中心是否相等
-func clustersEqual(a, b []color.RGBA) bool {
-	if len(a) != len(b) {
-		return false
-	}
-	for i := range a {
-		if a[i] != b[i] {
-			return false
-		}
-	}
-	return true
-}

color_test.go

@@ -160,44 +160,44 @@ func TestDistance_IgnoresAlpha(t *testing.T) {
 func TestClustersEqual_Equal(t *testing.T) {
 	a := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}, {0, 0, 255, 255}}
 	b := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}, {0, 0, 255, 255}}
-	if !clustersEqual(a, b) {
+	if !isArrayRGBAEqual(a, b) {
 		t.Error("clustersEqual should return true for identical slices")
 	}
 }
 
 func TestClustersEqual_NotEqual(t *testing.T) {
 	a := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}}
 	b := []color.RGBA{{255, 0, 0, 255}, {0, 0, 255, 255}}
-	if clustersEqual(a, b) {
+	if isArrayRGBAEqual(a, b) {
 		t.Error("clustersEqual should return false for different slices")
 	}
 }
 
 func TestClustersEqual_DifferentLength(t *testing.T) {
 	a := []color.RGBA{{255, 0, 0, 255}}
 	b := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}}
-	if clustersEqual(a, b) {
+	if isArrayRGBAEqual(a, b) {
 		t.Error("clustersEqual should return false for slices of different lengths")
 	}
 }
 
 func TestClustersEqual_Empty(t *testing.T) {
-	if !clustersEqual([]color.RGBA{}, []color.RGBA{}) {
+	if !isArrayRGBAEqual([]color.RGBA{}, []color.RGBA{}) {
 		t.Error("clustersEqual should return true for two empty slices")
 	}
 }
 
 func TestClustersEqual_OneEmpty(t *testing.T) {
 	a := []color.RGBA{{255, 0, 0, 255}}
-	if clustersEqual(a, []color.RGBA{}) {
+	if isArrayRGBAEqual(a, []color.RGBA{}) {
 		t.Error("clustersEqual should return false when one slice is empty")
 	}
 }
 
 func TestClustersEqual_SingleElement(t *testing.T) {
 	a := []color.RGBA{{100, 100, 100, 255}}
 	b := []color.RGBA{{100, 100, 100, 255}}
-	if !clustersEqual(a, b) {
+	if !isArrayRGBAEqual(a, b) {
 		t.Error("clustersEqual should return true for identical single-element slices")
 	}
 }
@@ -206,7 +206,7 @@ func TestClustersEqual_DiffersOnlyInAlpha(t *testing.T) {
 	a := []color.RGBA{{100, 100, 100, 255}}
 	b := []color.RGBA{{100, 100, 100, 0}}
 	// RGBA 结构体逐字段比较，Alpha 也参与比较
-	if clustersEqual(a, b) {
+	if isArrayRGBAEqual(a, b) {
 		t.Error("clustersEqual should return false when alpha differs")
 	}
 }
@@ -216,7 +216,7 @@ func TestClustersEqual_DiffersOnlyInAlpha(t *testing.T) {
 func TestTakecolor_ReturnsKColors(t *testing.T) {
 	img := solidImage(10, 10, color.RGBA{128, 64, 32, 255})
 	for k := 1; k <= 5; k++ {
-		result := takeThemeColorsKMeans(img, k)
+		result := TakeThemeColorsKMeans(img, k)
 		if len(result) != k {
 			t.Errorf("takecolor with k=%d returned %d colors, want %d", k, len(result), k)
 		}
@@ -226,7 +226,7 @@ func TestTakecolor_ReturnsKColors(t *testing.T) {
 func TestTakecolor_SolidColorK1(t *testing.T) {
 	c := color.RGBA{200, 100, 50, 255}
 	img := solidImage(20, 20, c)
-	result := takeThemeColorsKMeans(img, 1)
+	result := TakeThemeColorsKMeans(img, 1)
 	if len(result) != 1 {
 		t.Fatalf("expected 1 color, got %d", len(result))
 	}
@@ -242,7 +242,7 @@ func TestTakecolor_SolidColorKGreaterThan1(t *testing.T) {
 	// 故只验证：返回 k 个颜色，且其中至少一个与原始颜色完全匹配。
 	c := color.RGBA{10, 200, 150, 255}
 	img := solidImage(15, 15, c)
-	result := takeThemeColorsKMeans(img, 3)
+	result := TakeThemeColorsKMeans(img, 3)
 	if len(result) != 3 {
 		t.Fatalf("expected 3 colors, got %d", len(result))
 	}
@@ -264,7 +264,7 @@ func TestTakecolor_TwoDistinctColors(t *testing.T) {
 	img := twoColorImage(20, 20, Red, Blue)
 	const maxAttempts = 30
 	for range maxAttempts {
-		result := takeThemeColorsKMeans(img, 2)
+		result := TakeThemeColorsKMeans(img, 2)
 		if len(result) == 2 && colorInSlice(Red, result, 5) && colorInSlice(Blue, result, 5) {
 			return // 成功分离，测试通过
 		}
@@ -276,9 +276,9 @@ func TestTakecolor_Deterministic_SolidImage(t *testing.T) {
 	// 纯色图像下，无论随机种子如何，结果应完全一致
 	c := color.RGBA{77, 88, 99, 255}
 	img := solidImage(10, 10, c)
-	r1 := takeThemeColorsKMeans(img, 2)
-	r2 := takeThemeColorsKMeans(img, 2)
-	if !clustersEqual(r1, r2) {
+	r1 := TakeThemeColorsKMeans(img, 2)
+	r2 := TakeThemeColorsKMeans(img, 2)
+	if !isArrayRGBAEqual(r1, r2) {
 		t.Errorf("takecolor on solid image should be deterministic: r1=%v, r2=%v", r1, r2)
 	}
 }
@@ -296,7 +296,7 @@ func TestTakecolor_AllClustersHaveValidRGB(t *testing.T) {
 			})
 		}
 	}
-	result := takeThemeColorsKMeans(img, 4)
+	result := TakeThemeColorsKMeans(img, 4)
 	if len(result) != 4 {
 		t.Fatalf("expected 4 clusters, got %d", len(result))
 	}
@@ -329,7 +329,7 @@ func BenchmarkClustersEqual_Equal(b *testing.B) {
 	c := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}, {0, 0, 255, 255}, {128, 128, 128, 255}}
 	b.ResetTimer()
 	for range b.N {
-		clustersEqual(a, c)
+		isArrayRGBAEqual(a, c)
 	}
 }
 
@@ -338,7 +338,7 @@ func BenchmarkClustersEqual_NotEqual(b *testing.B) {
 	c := []color.RGBA{{255, 0, 0, 255}, {0, 255, 0, 255}, {0, 0, 255, 255}, {200, 200, 200, 255}}
 	b.ResetTimer()
 	for range b.N {
-		clustersEqual(a, c)
+		isArrayRGBAEqual(a, c)
 	}
 }
 
@@ -352,7 +352,7 @@ func BenchmarkTakecolor_16x16_K3(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takeThemeColorsKMeans(img, 3)
+		TakeThemeColorsKMeans(img, 3)
 	}
 }
 
@@ -366,7 +366,7 @@ func BenchmarkTakecolor_64x64_K4(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takeThemeColorsKMeans(img, 4)
+		TakeThemeColorsKMeans(img, 4)
 	}
 }
 
@@ -380,14 +380,14 @@ func BenchmarkTakecolor_128x128_K8(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takeThemeColorsKMeans(img, 8)
+		TakeThemeColorsKMeans(img, 8)
 	}
 }
 
 func BenchmarkTakecolor_SolidColor_K5(b *testing.B) {
 	img := solidImage(64, 64, color.RGBA{200, 100, 50, 255})
 	b.ResetTimer()
 	for range b.N {
-		takeThemeColorsKMeans(img, 5)
+		TakeThemeColorsKMeans(img, 5)
 	}
 }

context.go

@@ -1366,5 +1366,5 @@ func (dc *Context) String() string {
 //
 // TakeThemeColorsKMeans 使用 k-means 算法从已绘制图像中提取 k 个主色。
 func (dc *Context) TakeThemeColorsKMeans(k int) []color.RGBA {
-	return takeThemeColorsKMeans(dc.im, k)
+	return TakeThemeColorsKMeans(dc.im, k)
 }

font.go

@@ -0,0 +1,58 @@
+package gg
+
+import (
+	"os"
+
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/opentype"
+)
+
+// LoadFontFace is a helper function to load the specified font file with
+// the specified point size. Note that the returned `font.Face` objects
+// are not thread safe and cannot be used in parallel across goroutines.
+// You can usually just use the Context.LoadFontFace function instead of
+// this package-level function.
+//
+// LoadFontFace 是一个辅助函数，用于加载指定点大小的指定字体文件。
+// 请注意，返回的 `font.Face` 对象不是线程安全的，不能跨 goroutine 并行使用。
+// 您通常可以只使用 Context.LoadFontFace 函数而不是这个包级函数。
+func LoadFontFace(path string, points float64) (face font.Face, err error) {
+	fontBytes, err := os.ReadFile(path)
+	if err != nil {
+		return
+	}
+	f, err := opentype.ParseCollection(fontBytes)
+	if err != nil {
+		return
+	}
+	fnf, err := f.Font(0)
+	if err != nil {
+		return
+	}
+	face, err = opentype.NewFace(fnf, &opentype.FaceOptions{
+		Size: points,
+		DPI:  72,
+		// Hinting: font.HintingFull,
+	})
+	return
+}
+
+// ParseFontFace 是一个辅助函数，用于加载指定点大小的指定字体文件。
+// 请注意，返回的 `font.Face` 对象不是线程安全的，不能跨 goroutine 并行使用。
+// 您通常可以只使用 Context.LoadFontFace 函数而不是这个包级函数。
+func ParseFontFace(b []byte, points float64) (face font.Face, err error) {
+	f, err := opentype.ParseCollection(b)
+	if err != nil {
+		return
+	}
+	fnf, err := f.Font(0)
+	if err != nil {
+		return
+	}
+	face, err = opentype.NewFace(fnf, &opentype.FaceOptions{
+		Size: points,
+		DPI:  72,
+		// Hinting: font.HintingFull,
+	})
+	return
+}

image.go

@@ -0,0 +1,62 @@
+package gg
+
+import (
+	"image"
+	"os"
+
+	"github.com/fumiama/imgsz"
+	"golang.org/x/image/draw"
+)
+
+// ImageToRGBA converts an image.Image to *image.RGBA.
+//
+// ImageToRGBA 将 image.Image 转换为 *image.RGBA。
+func ImageToRGBA(src image.Image) *image.RGBA {
+	bounds := src.Bounds()
+	dst := image.NewRGBA(bounds)
+	draw.Draw(dst, bounds, src, bounds.Min, draw.Src)
+	return dst
+}
+
+// ImageToRGBA64 converts an image.Image to *image.RGBA64.
+//
+// ImageToRGBA64 将 image.Image 转换为 *image.RGBA64。
+func ImageToRGBA64(src image.Image) *image.RGBA64 {
+	bounds := src.Bounds()
+	dst := image.NewRGBA64(bounds)
+	draw.Draw(dst, bounds, src, bounds.Min, draw.Src)
+	return dst
+}
+
+// ImageToNRGBA converts an image.Image to *image.NRGBA.
+//
+// ImageToNRGBA 将 image.Image 转换为 *image.NRGBA。
+func ImageToNRGBA(src image.Image) *image.NRGBA {
+	bounds := src.Bounds()
+	dst := image.NewNRGBA(bounds)
+	draw.Draw(dst, bounds, src, bounds.Min, draw.Src)
+	return dst
+}
+
+// ImageToNRGBA64 converts an image.Image to *image.NRGBA64.
+//
+// ImageToNRGBA64 将 image.Image 转换为 *image.NRGBA64。
+func ImageToNRGBA64(src image.Image) *image.NRGBA64 {
+	bounds := src.Bounds()
+	dst := image.NewNRGBA64(bounds)
+	draw.Draw(dst, bounds, src, bounds.Min, draw.Src)
+	return dst
+}
+
+// GetImageWxH returns the width and height of the image at the given path.
+//
+// GetImageWxH 返回指定路径图片的宽度和高度。
+func GetImageWxH(path string) (int, int, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return 0, 0, err
+	}
+	defer f.Close()
+	sz, _, err := imgsz.DecodeSize(f)
+	return sz.Width, sz.Height, err
+}