optimize: new unsafe syntax

Author: fumiama

color.go

@@ -26,9 +26,9 @@ var (
 	Opaque  = color.RGBA{0, 0, 0, 0}
 )
 
-// takecolor 实现基于k-means算法的图像取色算法
-func takecolor(img image.Image, k int) []color.RGBA {
-	rgbaimg := imageToRGBA(img)
+// 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 {
+	rgbaimg := ImageToRGBA(img)
 	pixels := unsafe.Slice(
 		(*color.RGBA)(unsafe.Pointer(unsafe.SliceData(rgbaimg.Pix))),
 		uintptr(len(rgbaimg.Pix))/unsafe.Sizeof(color.RGBA{}),

color_test.go

@@ -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 := takecolor(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 := takecolor(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 := takecolor(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 := takecolor(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
 		}
@@ -276,8 +276,8 @@ 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 := takecolor(img, 2)
-	r2 := takecolor(img, 2)
+	r1 := takeThemeColorsKMeans(img, 2)
+	r2 := takeThemeColorsKMeans(img, 2)
 	if !clustersEqual(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 := takecolor(img, 4)
+	result := takeThemeColorsKMeans(img, 4)
 	if len(result) != 4 {
 		t.Fatalf("expected 4 clusters, got %d", len(result))
 	}
@@ -352,7 +352,7 @@ func BenchmarkTakecolor_16x16_K3(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takecolor(img, 3)
+		takeThemeColorsKMeans(img, 3)
 	}
 }
 
@@ -366,7 +366,7 @@ func BenchmarkTakecolor_64x64_K4(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takecolor(img, 4)
+		takeThemeColorsKMeans(img, 4)
 	}
 }
 
@@ -380,14 +380,14 @@ func BenchmarkTakecolor_128x128_K8(b *testing.B) {
 	}
 	b.ResetTimer()
 	for range b.N {
-		takecolor(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 {
-		takecolor(img, 5)
+		takeThemeColorsKMeans(img, 5)
 	}
 }

context.go

@@ -129,7 +129,7 @@ func NewContext(width, height int) *Context {
 // 将指定图像复制到一个新的 image.RGBA
 // 并准备渲染到该图像上的上下文。
 func NewContextForImage(im image.Image) *Context {
-	return NewContextForRGBA(imageToRGBA(im))
+	return NewContextForRGBA(ImageToRGBA(im))
 }
 
 // NewContextForRGBA prepares a context for rendering onto the specified image.
@@ -820,12 +820,10 @@ func (dc *Context) InvertMask() {
 	if dc.mask == nil {
 		dc.mask = image.NewAlpha(dc.im.Bounds())
 	} else {
-		var u64s []uint64
-		raws := (*slice)(unsafe.Pointer(&dc.mask.Pix))
-		rawu64s := (*slice)(unsafe.Pointer(&u64s))
-		rawu64s.data = raws.data
-		rawu64s.len = raws.len / 8
-		rawu64s.cap = raws.cap / 8
+		u64s := unsafe.Slice((*uint64)(
+			unsafe.Pointer(unsafe.SliceData(dc.mask.Pix))),
+			len(dc.mask.Pix)/8,
+		)
 		for i, v := range u64s {
 			u64s[i] = 0xffffffff_ffffffff - v
 		}
@@ -1364,9 +1362,9 @@ func (dc *Context) String() string {
 	return sb.String()
 }
 
-// TakeColor extracts the k dominant colors from the drawn image using k-means.
+// TakeThemeColorsKMeans extracts the k dominant colors from the drawn image using k-means.
 //
-// TakeColor 使用 k-means 算法从已绘制图像中提取 k 个主色。
-func (dc *Context) TakeColor(k int) []color.RGBA {
-	return takecolor(dc.im, k)
+// 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)
 }

path.go

@@ -8,8 +8,8 @@ import (
 )
 
 func flattenPath(p raster.Path) [][]Point {
-	var result [][]Point
-	var path []Point
+	var result = make([][]Point, len(p)*2)
+	var path = make([]Point, 0, len(p)*2)
 	var cx, cy float64
 	for i := 0; i < len(p); {
 		switch p[i] {
@@ -64,13 +64,13 @@ func flattenPath(p raster.Path) [][]Point {
 }
 
 func dashPath(paths [][]Point, dashes []float64, offset float64) [][]Point {
-	var result [][]Point
 	if len(dashes) == 0 {
 		return paths
 	}
 	if len(dashes) == 1 {
 		dashes = append(dashes, dashes[0])
 	}
+	var result = make([][]Point, 0, len(paths)*2)
 	for _, path := range paths {
 		if len(path) < 2 {
 			continue
@@ -100,7 +100,7 @@ func dashPath(paths [][]Point, dashes []float64, offset float64) [][]Point {
 			}
 		}
 
-		var segment []Point
+		var segment = make([]Point, 0, (len(path)-pathIndex)*2)
 		segment = append(segment, previous)
 		for pathIndex < len(path) {
 			dashLength := dashes[dashIndex]
@@ -114,7 +114,7 @@ func dashPath(paths [][]Point, dashes []float64, offset float64) [][]Point {
 				if dashIndex%2 == 0 && len(segment) > 1 {
 					result = append(result, segment)
 				}
-				segment = make([]Point, 0, 1)
+				segment = make([]Point, 0, (len(path)-pathIndex)*2)
 				segment = append(segment, p)
 				segmentLength = 0
 				previous = p
@@ -134,7 +134,7 @@ func dashPath(paths [][]Point, dashes []float64, offset float64) [][]Point {
 }
 
 func rasterPath(paths [][]Point) raster.Path {
-	var result raster.Path
+	var result = make(raster.Path, 0, len(paths))
 	for _, path := range paths {
 		var previous fixed.Point26_6
 		for i, point := range path {

util.go

@@ -34,11 +34,6 @@ func Degrees(radians float64) float64 {
 //
 // ImageToRGBA 将 image.Image 转换为 *image.RGBA。
 func ImageToRGBA(src image.Image) *image.RGBA {
-	return imageToRGBA(src)
-}
-
-// image.Image 转为 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)
@@ -186,9 +181,9 @@ func ParseFontFace(b []byte, points float64) (face font.Face, err error) {
 	return
 }
 
-// TakeColor extracts the k dominant colors from an image using k-means.
+// TakeThemeColorsKMeans extracts the k dominant colors from an image using k-means.
 //
-// TakeColor 使用 k-means 算法从图像中提取 k 个主色。
-func TakeColor(img image.Image, k int) []color.RGBA {
-	return takecolor(img, k)
+// 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 {
+	return takeThemeColorsKMeans(img, k)
 }