wasm: updated faceblur demo

2025-09-26 20:31:20 +08:00 · 2022-05-03 10:52:37 +03:00
parent a77d2f9f4c
commit 4bf38e072f
4 changed files with 65 additions and 468 deletions
--- a/faceblur/canvas.go
+++ b/faceblur/canvas.go
@@ -4,10 +4,13 @@ import (
 	"fmt"
 	"image"
 	"image/color"
+	"image/draw"
 	"math"
 	"syscall/js"

 	"github.com/esimov/pigo-wasm-demos/detector"
+	ellipse "github.com/esimov/pigo-wasm-demos/draw"
+	"github.com/esimov/stackblur-go"
 )

 // Canvas struct holds the Javascript objects needed for the Canvas creation
@@ -47,7 +50,7 @@ const (
 	maxBlurRadius = 50
 )

-var det *detector.Detector
+var pigo *detector.Detector

 // NewCanvas creates and initializes the new Canvas element
 func NewCanvas() *Canvas {
@@ -72,7 +75,7 @@ func NewCanvas() *Canvas {

 	c.blurRadius = 20

-	det = detector.NewDetector()
+	pigo = detector.NewDetector()
 	return &c
 }

@@ -82,12 +85,12 @@ func (c *Canvas) Render() error {
 	var data = make([]byte, width*height*4)
 	c.done = make(chan struct{})

-	err := det.UnpackCascades()
+	err := pigo.UnpackCascades()
 	if err != nil {
 		return err
 	}
 	c.renderer = js.FuncOf(func(this js.Value, args []js.Value) interface{} {
-		go func() {
+		go func() error {
 			c.window.Get("stats").Call("begin")

 			c.reqID = c.window.Call("requestAnimationFrame", c.renderer)
@@ -106,12 +109,15 @@ func (c *Canvas) Render() error {
 			// and the memory will keep up increasing by each iteration.
 			data = make([]byte, len(data))

-			res := det.DetectFaces(gray, height, width)
+			res := pigo.DetectFaces(gray, height, width)
 			if len(res) > 0 {
-				c.drawDetection(data, res)
+				if err := c.drawDetection(data, res); err != nil {
+					return err
+				}
 			}
-
 			c.window.Get("stats").Call("end")
+
+			return nil
 		}()
 		return nil
 	})
@@ -121,6 +127,7 @@ func (c *Canvas) Render() error {
 	c.window.Call("requestAnimationFrame", c.renderer)
 	c.detectKeyPress()
 	<-c.done
+
 	return nil
 }

@@ -208,19 +215,14 @@ func (c *Canvas) pixToImage(pixels []uint8, dim int) image.Image {
 	c.frame = image.NewNRGBA(image.Rect(0, 0, dim, dim))
 	bounds := c.frame.Bounds()
 	dx, dy := bounds.Max.X, bounds.Max.Y
-	col := color.NRGBA{
-		R: uint8(0),
-		G: uint8(0),
-		B: uint8(0),
-		A: uint8(255),
-	}
+	col := color.NRGBA{}

 	for y := bounds.Min.Y; y < dy; y++ {
 		for x := bounds.Min.X; x < dx*4; x += 4 {
-			col.R = uint8(pixels[x+y*dx*4])
-			col.G = uint8(pixels[x+y*dx*4+1])
-			col.B = uint8(pixels[x+y*dx*4+2])
-			col.A = uint8(pixels[x+y*dx*4+3])
+			col.R = pixels[x+y*dx*4]
+			col.G = pixels[x+y*dx*4+1]
+			col.B = pixels[x+y*dx*4+2]
+			col.A = pixels[x+y*dx*4+3]

 			c.frame.SetNRGBA(y, int(x/4), col)
 		}
@@ -242,26 +244,25 @@ func (c *Canvas) imgToPix(img image.Image) []uint8 {
 	return pixels
 }

-// pixelateDetectedRegion pixelates the detected face region
-func (c *Canvas) blurDetectedRegion(data []uint8, dets []int) []uint8 {
-	// Converts the array buffer to an image
-	img := c.pixToImage(data, int(float64(dets[2])*0.8))
+// blurFace blures out the detected face region
+func (c *Canvas) blurFace(src image.Image, scale int) (image.Image, error) {
+	img, err := stackblur.Process(src, c.blurRadius)
+	if err != nil {
+		return nil, err
+	}

-	blured := Blur(img, c.blurRadius)
-	return c.imgToPix(blured)
+	return img, nil
 }

 // drawDetection draws the detected faces and eyes.
-func (c *Canvas) drawDetection(data []uint8, dets [][]int) {
-	for i := 0; i < len(dets); i++ {
-		if dets[i][3] > 50 {
+func (c *Canvas) drawDetection(data []uint8, dets [][]int) error {
+	for i, det := range dets {
+		if det[3] > 50 {
 			c.ctx.Call("beginPath")
 			c.ctx.Set("lineWidth", 2)
 			c.ctx.Set("strokeStyle", "rgba(255, 0, 0, 0.5)")

-			row, col, scale := dets[i][1], dets[i][0], dets[i][2]
-			col = col + int(float64(col)*0.1)
-			scale = int(float64(scale) * 0.8)
+			row, col, scale := det[1], det[0], det[2]

 			if c.isBlured {
 				// Substract the image under the detected face region.
@@ -270,9 +271,36 @@ func (c *Canvas) drawDetection(data []uint8, dets [][]int) {
 				uint8Arr := js.Global().Get("Uint8Array").New(subimg)
 				js.CopyBytesToGo(imgData, uint8Arr)

-				buffer := c.blurDetectedRegion(imgData, dets[i])
+				unionMask := image.NewNRGBA(image.Rect(0, 0, scale, scale))
+				// Add to union mask
+				ellipse := &ellipse.Ellipse{
+					Cx: row,
+					Cy: col,
+					Ry: int(float64(scale) * 0.8 / 2.2),
+					Rx: int(float64(scale) * 0.8 / 1.55),
+				}
+				draw.Draw(unionMask, unionMask.Bounds(), ellipse, image.Point{X: row - scale/2, Y: col - scale/2}, draw.Over)
+
+				// Converts the buffer array to an image.
+				img := c.pixToImage(imgData, scale)
+
+				// Create a new image and draw the webcam frame captures into it.
+				newImg := image.NewNRGBA(image.Rect(0, 0, scale, scale))
+				draw.Draw(newImg, newImg.Bounds(), img, newImg.Bounds().Min, draw.Over)
+
+				// Apply the blur effect over the obtained pixel data converted to image.
+				blurred, err := c.blurFace(newImg, scale)
+				if err != nil {
+					return err
+				}
+				faceTemplate := image.NewNRGBA(image.Rect(0, 0, scale, scale))
+				draw.Draw(faceTemplate, img.Bounds(), blurred, image.Point{}, draw.Over)
+
+				// Draw the triangled image through the facemask and on top of the source.
+				draw.DrawMask(img.(draw.Image), img.Bounds(), faceTemplate, image.Point{}, unionMask, image.Point{}, draw.Over)
+
 				uint8Arr = js.Global().Get("Uint8Array").New(scale * scale * 4)
-				js.CopyBytesToJS(uint8Arr, buffer)
+				js.CopyBytesToJS(uint8Arr, c.imgToPix(img))

 				uint8Clamped := js.Global().Get("Uint8ClampedArray").New(uint8Arr)
 				rawData := js.Global().Get("ImageData").New(uint8Clamped, scale)
@@ -287,14 +315,14 @@ func (c *Canvas) drawDetection(data []uint8, dets [][]int) {
 			}

 			if c.showPupil {
-				leftPupil := det.DetectLeftPupil(dets[i])
+				leftPupil := pigo.DetectLeftPupil(dets[i])
 				if leftPupil != nil {
 					col, row, scale := leftPupil.Col, leftPupil.Row, leftPupil.Scale/8
 					c.ctx.Call("moveTo", col+int(scale), row)
 					c.ctx.Call("arc", col, row, scale, 0, 2*math.Pi, true)
 				}

-				rightPupil := det.DetectRightPupil(dets[i])
+				rightPupil := pigo.DetectRightPupil(dets[i])
 				if rightPupil != nil {
 					col, row, scale := rightPupil.Col, rightPupil.Row, rightPupil.Scale/8
 					c.ctx.Call("moveTo", col+int(scale), row)
@@ -304,6 +332,7 @@ func (c *Canvas) drawDetection(data []uint8, dets [][]int) {
 			}
 		}
 	}
+	return nil
 }

 // detectKeyPress listen for the keypress event and retrieves the key code.
--- a/faceblur/stackblur.go
+++ b/faceblur/stackblur.go
@@ -1,435 +0,0 @@
-// Go implementation of the StackBlur algorithm
-// http://incubator.quasimondo.com/processing/fast_blur_deluxe.php
-
-package faceblur
-
-import (
-	"image"
-	"image/color"
-)
-
-// blurStack is a linked list containing the color value and a pointer to the next struct.
-type blurStack struct {
-	r, g, b, a uint32
-	next       *blurStack
-}
-
-var mulTable = []uint32{
-	512, 512, 456, 512, 328, 456, 335, 512, 405, 328, 271, 456, 388, 335, 292, 512,
-	454, 405, 364, 328, 298, 271, 496, 456, 420, 388, 360, 335, 312, 292, 273, 512,
-	482, 454, 428, 405, 383, 364, 345, 328, 312, 298, 284, 271, 259, 496, 475, 456,
-	437, 420, 404, 388, 374, 360, 347, 335, 323, 312, 302, 292, 282, 273, 265, 512,
-	497, 482, 468, 454, 441, 428, 417, 405, 394, 383, 373, 364, 354, 345, 337, 328,
-	320, 312, 305, 298, 291, 284, 278, 271, 265, 259, 507, 496, 485, 475, 465, 456,
-	446, 437, 428, 420, 412, 404, 396, 388, 381, 374, 367, 360, 354, 347, 341, 335,
-	329, 323, 318, 312, 307, 302, 297, 292, 287, 282, 278, 273, 269, 265, 261, 512,
-	505, 497, 489, 482, 475, 468, 461, 454, 447, 441, 435, 428, 422, 417, 411, 405,
-	399, 394, 389, 383, 378, 373, 368, 364, 359, 354, 350, 345, 341, 337, 332, 328,
-	324, 320, 316, 312, 309, 305, 301, 298, 294, 291, 287, 284, 281, 278, 274, 271,
-	268, 265, 262, 259, 257, 507, 501, 496, 491, 485, 480, 475, 470, 465, 460, 456,
-	451, 446, 442, 437, 433, 428, 424, 420, 416, 412, 408, 404, 400, 396, 392, 388,
-	385, 381, 377, 374, 370, 367, 363, 360, 357, 354, 350, 347, 344, 341, 338, 335,
-	332, 329, 326, 323, 320, 318, 315, 312, 310, 307, 304, 302, 299, 297, 294, 292,
-	289, 287, 285, 282, 280, 278, 275, 273, 271, 269, 267, 265, 263, 261, 259,
-}
-
-var shgTable = []uint32{
-	9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17,
-	17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19,
-	19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20,
-	20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21,
-	21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
-	21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22,
-	22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
-	22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23,
-	23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
-	23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
-	23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
-	23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-}
-
-// newBlurStack initialize the StackBlur algorithm by returning a new struct of type blurStack.
-func (bs *blurStack) newBlurStack() *blurStack {
-	return &blurStack{bs.r, bs.g, bs.b, bs.a, bs.next}
-}
-
-// Blur takes an image as input and returns it's blurred version by applying the blur radius defined as parameter.
-func Blur(src image.Image, radius uint32) image.Image {
-	var stackEnd, stackIn, stackOut *blurStack
-	var width, height = uint32(src.Bounds().Dx()), uint32(src.Bounds().Dy())
-	var (
-		div, widthMinus1, heightMinus1, radiusPlus1, sumFactor uint32
-		x, y, i, p, yp, yi, yw,
-		rSum, gSum, bSum, aSum,
-		rOutSum, gOutSum, bOutSum, aOutSum,
-		rInSum, gInSum, bInSum, aInSum,
-		pr, pg, pb, pa uint32
-	)
-
-	img := toNRGBA(src)
-
-	div = radius + radius + 1
-	widthMinus1 = width - 1
-	heightMinus1 = height - 1
-	radiusPlus1 = radius + 1
-	sumFactor = radiusPlus1 * (radiusPlus1 + 1) / 2
-
-	bs := blurStack{}
-	stackStart := bs.newBlurStack()
-	stack := stackStart
-
-	for i = 1; i < div; i++ {
-		stack.next = bs.newBlurStack()
-		stack = stack.next
-		if i == radiusPlus1 {
-			stackEnd = stack
-		}
-	}
-	stack.next = stackStart
-
-	mulSum := mulTable[radius]
-	shgSum := shgTable[radius]
-
-	for y = 0; y < height; y++ {
-		rInSum, gInSum, bInSum, aInSum, rSum, gSum, bSum, aSum = 0, 0, 0, 0, 0, 0, 0, 0
-
-		pr = uint32(img.Pix[yi])
-		pg = uint32(img.Pix[yi+1])
-		pb = uint32(img.Pix[yi+2])
-		pa = uint32(img.Pix[yi+3])
-
-		rOutSum = radiusPlus1 * pr
-		gOutSum = radiusPlus1 * pg
-		bOutSum = radiusPlus1 * pb
-		aOutSum = radiusPlus1 * pa
-
-		rSum += sumFactor * pr
-		gSum += sumFactor * pg
-		bSum += sumFactor * pb
-		aSum += sumFactor * pa
-
-		stack = stackStart
-
-		for i = 0; i < radiusPlus1; i++ {
-			stack.r = pr
-			stack.g = pg
-			stack.b = pb
-			stack.a = pa
-			stack = stack.next
-		}
-
-		for i = 1; i < radiusPlus1; i++ {
-			var diff uint32
-			if widthMinus1 < i {
-				diff = widthMinus1
-			} else {
-				diff = i
-			}
-			p = yi + (diff << 2)
-			pr = uint32(img.Pix[p])
-			pg = uint32(img.Pix[p+1])
-			pb = uint32(img.Pix[p+2])
-			pa = uint32(img.Pix[p+3])
-
-			stack.r = pr
-			stack.g = pg
-			stack.b = pb
-			stack.a = pa
-
-			rSum += stack.r * (radiusPlus1 - i)
-			gSum += stack.g * (radiusPlus1 - i)
-			bSum += stack.b * (radiusPlus1 - i)
-			aSum += stack.a * (radiusPlus1 - i)
-
-			rInSum += pr
-			gInSum += pg
-			bInSum += pb
-			aInSum += pa
-
-			stack = stack.next
-		}
-		stackIn = stackStart
-		stackOut = stackEnd
-
-		for x = 0; x < width; x++ {
-			pa = (aSum * mulSum) >> shgSum
-			img.Pix[yi+3] = uint8(pa)
-
-			if pa != 0 {
-				img.Pix[yi] = uint8((rSum * mulSum) >> shgSum)
-				img.Pix[yi+1] = uint8((gSum * mulSum) >> shgSum)
-				img.Pix[yi+2] = uint8((bSum * mulSum) >> shgSum)
-			} else {
-				img.Pix[yi] = 0
-				img.Pix[yi+1] = 0
-				img.Pix[yi+2] = 0
-			}
-
-			rSum -= rOutSum
-			gSum -= gOutSum
-			bSum -= bOutSum
-			aSum -= aOutSum
-
-			rOutSum -= stackIn.r
-			gOutSum -= stackIn.g
-			bOutSum -= stackIn.b
-			aOutSum -= stackIn.a
-
-			p = x + radius + 1
-
-			if p > widthMinus1 {
-				p = widthMinus1
-			}
-			p = (yw + p) << 2
-
-			stackIn.r = uint32(img.Pix[p])
-			stackIn.g = uint32(img.Pix[p+1])
-			stackIn.b = uint32(img.Pix[p+2])
-			stackIn.a = uint32(img.Pix[p+3])
-
-			rInSum += stackIn.r
-			gInSum += stackIn.g
-			bInSum += stackIn.b
-			aInSum += stackIn.a
-
-			rSum += rInSum
-			gSum += gInSum
-			bSum += bInSum
-			aSum += aInSum
-
-			stackIn = stackIn.next
-
-			pr = stackOut.r
-			pg = stackOut.g
-			pb = stackOut.b
-			pa = stackOut.a
-
-			rOutSum += pr
-			gOutSum += pg
-			bOutSum += pb
-			aOutSum += pa
-
-			rInSum -= pr
-			gInSum -= pg
-			bInSum -= pb
-			aInSum -= pa
-
-			stackOut = stackOut.next
-
-			yi += 4
-		}
-		yw += width
-	}
-
-	for x = 0; x < width; x++ {
-		rInSum, gInSum, bInSum, aInSum, rSum, gSum, bSum, aSum = 0, 0, 0, 0, 0, 0, 0, 0
-
-		yi = x << 2
-		pr = uint32(img.Pix[yi])
-		pg = uint32(img.Pix[yi+1])
-		pb = uint32(img.Pix[yi+2])
-		pa = uint32(img.Pix[yi+3])
-
-		rOutSum = radiusPlus1 * pr
-		gOutSum = radiusPlus1 * pg
-		bOutSum = radiusPlus1 * pb
-		aOutSum = radiusPlus1 * pa
-
-		rSum += sumFactor * pr
-		gSum += sumFactor * pg
-		bSum += sumFactor * pb
-		aSum += sumFactor * pa
-
-		stack = stackStart
-
-		for i = 0; i < radiusPlus1; i++ {
-			stack.r = pr
-			stack.g = pg
-			stack.b = pb
-			stack.a = pa
-			stack = stack.next
-		}
-
-		yp = width
-
-		for i = 1; i <= radius; i++ {
-			yi = (yp + x) << 2
-			pr = uint32(img.Pix[yi])
-			pg = uint32(img.Pix[yi+1])
-			pb = uint32(img.Pix[yi+2])
-			pa = uint32(img.Pix[yi+3])
-
-			stack.r = pr
-			stack.g = pg
-			stack.b = pb
-			stack.a = pa
-
-			rSum += stack.r * (radiusPlus1 - i)
-			gSum += stack.g * (radiusPlus1 - i)
-			bSum += stack.b * (radiusPlus1 - i)
-			aSum += stack.a * (radiusPlus1 - i)
-
-			rInSum += pr
-			gInSum += pg
-			bInSum += pb
-			aInSum += pa
-
-			stack = stack.next
-
-			if i < heightMinus1 {
-				yp += width
-			}
-		}
-
-		yi = x
-		stackIn = stackStart
-		stackOut = stackEnd
-
-		for y = 0; y < height; y++ {
-			p = yi << 2
-			pa = (aSum * mulSum) >> shgSum
-			img.Pix[p+3] = uint8(pa)
-
-			if pa > 0 {
-				img.Pix[p] = uint8((rSum * mulSum) >> shgSum)
-				img.Pix[p+1] = uint8((gSum * mulSum) >> shgSum)
-				img.Pix[p+2] = uint8((bSum * mulSum) >> shgSum)
-			} else {
-				img.Pix[p] = 0
-				img.Pix[p+1] = 0
-				img.Pix[p+2] = 0
-			}
-
-			rSum -= rOutSum
-			gSum -= gOutSum
-			bSum -= bOutSum
-			aSum -= aOutSum
-
-			rOutSum -= stackIn.r
-			gOutSum -= stackIn.g
-			bOutSum -= stackIn.b
-			aOutSum -= stackIn.a
-
-			p = y + radiusPlus1
-
-			if p > heightMinus1 {
-				p = heightMinus1
-			}
-			p = (x + (p * width)) << 2
-
-			stackIn.r = uint32(img.Pix[p])
-			stackIn.g = uint32(img.Pix[p+1])
-			stackIn.b = uint32(img.Pix[p+2])
-			stackIn.a = uint32(img.Pix[p+3])
-
-			rInSum += stackIn.r
-			gInSum += stackIn.g
-			bInSum += stackIn.b
-			aInSum += stackIn.a
-
-			rSum += rInSum
-			gSum += gInSum
-			bSum += bInSum
-			aSum += aInSum
-
-			stackIn = stackIn.next
-
-			pr = stackOut.r
-			pg = stackOut.g
-			pb = stackOut.b
-			pa = stackOut.a
-
-			rOutSum += pr
-			gOutSum += pg
-			bOutSum += pb
-			aOutSum += pa
-
-			rInSum -= pr
-			gInSum -= pg
-			bInSum -= pb
-			aInSum -= pa
-
-			stackOut = stackOut.next
-
-			yi += width
-		}
-	}
-	return img
-}
-
-// toNRGBA converts any image type to *image.NRGBA with min-point at (0, 0).
-func toNRGBA(img image.Image) *image.NRGBA {
-	srcBounds := img.Bounds()
-	if srcBounds.Min.X == 0 && srcBounds.Min.Y == 0 {
-		if src0, ok := img.(*image.NRGBA); ok {
-			return src0
-		}
-	}
-	srcMinX := srcBounds.Min.X
-	srcMinY := srcBounds.Min.Y
-
-	dstBounds := srcBounds.Sub(srcBounds.Min)
-	dstW := dstBounds.Dx()
-	dstH := dstBounds.Dy()
-	dst := image.NewNRGBA(dstBounds)
-
-	switch src := img.(type) {
-	case *image.NRGBA:
-		rowSize := srcBounds.Dx() * 4
-		for dstY := 0; dstY < dstH; dstY++ {
-			di := dst.PixOffset(0, dstY)
-			si := src.PixOffset(srcMinX, srcMinY+dstY)
-			for dstX := 0; dstX < dstW; dstX++ {
-				copy(dst.Pix[di:di+rowSize], src.Pix[si:si+rowSize])
-			}
-		}
-	case *image.YCbCr:
-		for dstY := 0; dstY < dstH; dstY++ {
-			di := dst.PixOffset(0, dstY)
-			for dstX := 0; dstX < dstW; dstX++ {
-				srcX := srcMinX + dstX
-				srcY := srcMinY + dstY
-				siy := src.YOffset(srcX, srcY)
-				sic := src.COffset(srcX, srcY)
-				r, g, b := color.YCbCrToRGB(src.Y[siy], src.Cb[sic], src.Cr[sic])
-				dst.Pix[di+0] = r
-				dst.Pix[di+1] = g
-				dst.Pix[di+2] = b
-				dst.Pix[di+3] = 0xff
-				di += 4
-			}
-		}
-	case *image.Gray:
-		for dstY := 0; dstY < dstH; dstY++ {
-			di := dst.PixOffset(0, dstY)
-			si := src.PixOffset(srcMinX, srcMinY+dstY)
-			for dstX := 0; dstX < dstW; dstX++ {
-				c := src.Pix[si]
-				dst.Pix[di+0] = c
-				dst.Pix[di+1] = c
-				dst.Pix[di+2] = c
-				dst.Pix[di+3] = 0xff
-				di += 4
-				si += 2
-			}
-		}
-	default:
-		for dstY := 0; dstY < dstH; dstY++ {
-			di := dst.PixOffset(0, dstY)
-			for dstX := 0; dstX < dstW; dstX++ {
-				c := color.NRGBAModel.Convert(img.At(srcMinX+dstX, srcMinY+dstY)).(color.NRGBA)
-				dst.Pix[di+0] = c.R
-				dst.Pix[di+1] = c.G
-				dst.Pix[di+2] = c.B
-				dst.Pix[di+3] = c.A
-				di += 4
-			}
-		}
-	}
-
-	return dst
-}
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.18

 require (
 	github.com/esimov/pigo v1.4.5
+	github.com/esimov/stackblur-go v1.1.0
 	github.com/esimov/triangle v1.3.0
 	github.com/esimov/triangle/v2 v2.0.0
 	github.com/fogleman/gg v1.3.0
--- a/go.sum
+++ b/go.sum
@@ -1,6 +1,8 @@
 github.com/disintegration/imaging v1.6.2/go.mod h1:44/5580QXChDfwIclfc/PCwrr44amcmDAg8hxG0Ewe4=
 github.com/esimov/pigo v1.4.5 h1:ySG0QqMh02VNALvHnx04L1ScRu66N6XA5vLLga8GiLg=
 github.com/esimov/pigo v1.4.5/go.mod h1:SGkOUpm4wlEmQQJKlaymAkThY8/8iP+XE0gFo7g8G6w=
+github.com/esimov/stackblur-go v1.1.0 h1:fwnZJC/7sHFzu4CDMgdJ1QxMN/q3k5MGILuoU4hH6oQ=
+github.com/esimov/stackblur-go v1.1.0/go.mod h1:7PcTPCHHKStxbZvBkUlQJjRclqjnXtQ0NoORZt1AlHE=
 github.com/esimov/triangle v1.3.0 h1:8637fdGbeNNoax1BuXFPc5+lTCvi/XWKW8FNuehCSC4=
 github.com/esimov/triangle v1.3.0/go.mod h1:82lxRK5Bg56WTzWlp23OzXCIf1V5Q9O8Y2TcVpQ00eo=
 github.com/esimov/triangle/v2 v2.0.0 h1:bUAfG42rcQeQYLvSnvwcerlts8z8z7r3FCvdBppfRcA=