golang 六宫格、九宫格头像生成

图片示例就不传了，在原WordPress上。

//Merge6Grid 6宫格
//rule NO1:至少3张图 最多6张图
// NO2:第一张大小 60*60 其他大小 28*28 间隔4px 合成图大小102*102
// NO3:排列顺序 从左至右 从上到小 再 从右到左
// ++|
// ++|
// --|
func Merge6Grid(src []io.Reader, dst io.Writer) error {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Merge.recover:", r)
		}
	}()
	if len(src) < 3 || len(src) > 6 {
		panic("the pic num is between 3 and 6")
	}
	var err error
	imagePoints := getXy6Grid(len(src))

	//创建背景大图
	background := image.NewRGBA(image.Rect(0, 0, 100, 100))
	//设置背景为灰色
	for m := 0; m < 100; m++ {
		for n := 0; n < 100; n++ {
			//rgba := GetRGBA(0xC8CED4)
			background.SetRGBA(m, n, color.RGBA{127, 127, 127, 0})
		}
	}

	//背景图矩形圆角
	newBg, err := CreateRoundRectWithRGBA(background, 10)
	if err != nil {
		return err
	}

	//开始合成
	var width int
	for i, v := range imagePoints {
		x := v.x
		y := v.y

		if i == 0 {
			width = 60
		} else {
			width = 28
		}
		fOut := memory.NewWriter()

		//先缩略
		err = Scale(src[i], fOut, width, width, 100)
		if err != nil {
			return err
		}

		//矩形圆角
		rgba, err := CreateRoundRectWithoutColor(fOut, 6)
		if err != nil {
			return err
		}

		draw.Draw(newBg, newBg.Bounds(), rgba, rgba.Bounds().Min.Sub(image.Pt(x, y)), draw.Src)
	}

	return png.Encode(dst, newBg)
	//return jpeg.Encode(dst, newBg, nil)
}

//CreateRoundRect 创建圆角矩形 r为输入图像 r为圆角半径 color为圆角颜色
func CreateRoundRect(rd io.Reader, r int, c *color.RGBA) (*image.RGBA, error) {
	src, _, err := image.Decode(rd)
	if err != nil {
		return nil, err
	}

	b := src.Bounds()
	x := b.Dx()
	y := b.Dy()
	dst := image.NewRGBA(b)
	draw.Draw(dst, b, src, src.Bounds().Min, draw.Src)

	p1 := image.Point{r, r}
	p2 := image.Point{x - r, r}
	p3 := image.Point{r, y - r}
	p4 := image.Point{x - r, y - r}

	for m := 0; m < x; m++ {
		for n := 0; n < y; n++ {
			if (p1.X-m)*(p1.X-m)+(p1.Y-n)*(p1.Y-n) > r*r && m <= p1.X && n <= p1.Y {
				dst.Set(m, n, c)
			} else if (p2.X-m)*(p2.X-m)+(p2.Y-n)*(p2.Y-n) > r*r && m > p2.X && n <= p2.Y {
				dst.Set(m, n, c)
			} else if (p3.X-m)*(p3.X-m)+(p3.Y-n)*(p3.Y-n) > r*r && m <= p3.X && n > p3.Y {
				dst.Set(m, n, c)
			} else if (p4.X-m)*(p4.X-m)+(p4.Y-n)*(p4.Y-n) > r*r && m > p4.X && n > p4.Y {
				dst.Set(m, n, c)
			}
		}
	}
	return dst, nil
}

func CreateRoundRectWithoutColor(rd io.Reader, r int) (*image.RGBA, error) {
	src, _, err := image.Decode(rd)
	if err != nil {
		return nil, err
	}

	b := src.Bounds()
	x := b.Dx()
	y := b.Dy()
	dst := image.NewRGBA(b)

	p1 := image.Point{r, r}
	p2 := image.Point{x - r, r}
	p3 := image.Point{r, y - r}
	p4 := image.Point{x - r, y - r}

	for m := 0; m < x; m++ {
		for n := 0; n < y; n++ {
			if (p1.X-m)*(p1.X-m)+(p1.Y-n)*(p1.Y-n) > r*r && m <= p1.X && n <= p1.Y {
			} else if (p2.X-m)*(p2.X-m)+(p2.Y-n)*(p2.Y-n) > r*r && m > p2.X && n <= p2.Y {
			} else if (p3.X-m)*(p3.X-m)+(p3.Y-n)*(p3.Y-n) > r*r && m <= p3.X && n > p3.Y {
			} else if (p4.X-m)*(p4.X-m)+(p4.Y-n)*(p4.Y-n) > r*r && m > p4.X && n > p4.Y {
			} else {
				dst.Set(m, n, src.At(m, n))
			}
		}
	}
	return dst, nil
}

func CreateRoundRectWithRGBA(src *image.RGBA, r int) (*image.RGBA, error) {
	b := src.Bounds()
	x := b.Dx()
	y := b.Dy()
	dst := image.NewRGBA(b)

	p1 := image.Point{r, r}
	p2 := image.Point{x - r, r}
	p3 := image.Point{r, y - r}
	p4 := image.Point{x - r, y - r}

	for m := 0; m < x; m++ {
		for n := 0; n < y; n++ {
			if (p1.X-m)*(p1.X-m)+(p1.Y-n)*(p1.Y-n) > r*r && m <= p1.X && n <= p1.Y {
			} else if (p2.X-m)*(p2.X-m)+(p2.Y-n)*(p2.Y-n) > r*r && m > p2.X && n <= p2.Y {
			} else if (p3.X-m)*(p3.X-m)+(p3.Y-n)*(p3.Y-n) > r*r && m <= p3.X && n > p3.Y {
			} else if (p4.X-m)*(p4.X-m)+(p4.Y-n)*(p4.Y-n) > r*r && m > p4.X && n > p4.Y {
			} else {
				dst.Set(m, n, src.At(m, n))
			}
		}
	}
	return dst, nil
}

//0xC8CED4
func GetRGBA(c int) *color.RGBA {
	var cl color.RGBA
	cl.R = uint8((c >> 16) & 0xFF)
	cl.G = uint8((c >> 8) & 0xFF)
	cl.B = uint8(c & 0xFF)
	return &cl
}
func getXy6Grid(size int) []*Point {
	s := make([]*Point, size)
	_x, _y := 4, 4
	s[0] = &Point{_x, _y}
	s[1] = &Point{60 + 2*_x, _y}
	s[2] = &Point{60 + 2*_x, 28 + 2*_y}
	if size >= 4 {
		s[3] = &Point{60 + 2*_x, 28*2 + 3*_y}
	}
	if size >= 5 {
		s[4] = &Point{28 + 2*_x, 60 + 2*_y}
	}
	if size >= 6 {
		s[5] = &Point{_x, 60 + 2*_y}
	}

	return s
}

以下是仿微信群头像

//Merge 九宫格头像合成 固定新图大小132*132px 间隙3px
//至少一张图片
func Merge(src []io.Reader, dst io.Writer) error {
	defer func() {
		if r := recover(); r != nil {
			log.Println("Merge.recover:", r)
		}
	}()
	var err error
	imagePoints := getXy(len(src))
	width := getWidth(len(src))

	//创建背景图
	background := image.NewRGBA(image.Rect(0, 0, 132, 132))

	//设置背景为灰色
	for m := 0; m < 132; m++ {
		for n := 0; n < 132; n++ {
			background.SetRGBA(m, n, color.RGBA{127, 127, 127, 0})
		}
	}

	for i, v := range imagePoints {
		x := v.x
		y := v.y

		fOut := memory.NewWriter()

		err = Scale(src[i], fOut, width, width, 100)
		if err != nil {
			return err
		}

		//file2draw, err := jpeg.Decode(fOut)
		file2draw, _, err := image.Decode(fOut)
		if err != nil {
			return err
		}
		draw.Draw(background, background.Bounds(), file2draw, file2draw.Bounds().Min.Sub(image.Pt(x, y)), draw.Src)
	}

	return jpeg.Encode(dst, background, nil)
}

type Point struct {
	x, y int
}

func getXy(size int) []*Point {
	s := make([]*Point, size)
	var _x, _y int

	if size == 1 {
		_x, _y = 6, 6
		s[0] = &Point{_x, _y}
	}
	if size == 2 {
		_x, _y = 4, 4
		s[0] = &Point{_x, 132/2 - 60/2}
		s[1] = &Point{60 + 2*_x, 132/2 - 60/2}
	}
	if size == 3 {
		_x, _y = 4, 4
		s[0] = &Point{132/2 - 60/2, _y}
		s[1] = &Point{_x, 60 + 2*_y}
		s[2] = &Point{60 + 2*_y, 60 + 2*_y}
	}
	if size == 4 {
		_x, _y = 4, 4
		s[0] = &Point{_x, _y}
		s[1] = &Point{_x*2 + 60, _y}
		s[2] = &Point{_x, 60 + 2*_y}
		s[3] = &Point{60 + 2*_y, 60 + 2*_y}
	}
	if size == 5 {
		_x, _y = 3, 3
		s[0] = &Point{(132 - 40*2 - _x) / 2, (132 - 40*2 - _y) / 2}
		s[1] = &Point{((132-40*2-_x)/2 + 40 + _x), (132 - 40*2 - _y) / 2}
		s[2] = &Point{_x, ((132-40*2-_x)/2 + 40 + _y)}
		s[3] = &Point{(_x*2 + 40), ((132-40*2-_x)/2 + 40 + _y)}
		s[4] = &Point{(_x*3 + 40*2), ((132-40*2-_x)/2 + 40 + _y)}
	}
	if size == 6 {
		_x, _y = 3, 3
		s[0] = &Point{_x, ((132 - 40*2 - _x) / 2)}
		s[1] = &Point{(_x*2 + 40), ((132 - 40*2 - _x) / 2)}
		s[2] = &Point{(_x*3 + 40*2), ((132 - 40*2 - _x) / 2)}
		s[3] = &Point{_x, ((132-40*2-_x)/2 + 40 + _y)}
		s[4] = &Point{(_x*2 + 40), ((132-40*2-_x)/2 + 40 + _y)}
		s[5] = &Point{(_x*3 + 40*2), ((132-40*2-_x)/2 + 40 + _y)}
	}

	if size == 7 {
		_x, _y = 3, 3
		s[0] = &Point{(132 - 40) / 2, _y}
		s[1] = &Point{_x, (_y*2 + 40)}
		s[2] = &Point{(_x*2 + 40), (_y*2 + 40)}
		s[3] = &Point{(_x*3 + 40*2), (_y*2 + 40)}
		s[4] = &Point{_x, (_y*3 + 40*2)}
		s[5] = &Point{(_x*2 + 40), (_y*3 + 40*2)}
		s[6] = &Point{(_x*3 + 40*2), (_y*3 + 40*2)}
	}
	if size == 8 {
		_x, _y = 3, 3
		s[0] = &Point{(132 - 80 - _x) / 2, _y}
		s[1] = &Point{((132-80-_x)/2 + _x + 40), _y}
		s[2] = &Point{_x, (_y*2 + 40)}
		s[3] = &Point{(_x*2 + 40), (_y*2 + 40)}
		s[4] = &Point{(_x*3 + 40*2), (_y*2 + 40)}
		s[5] = &Point{_x, (_y*3 + 40*2)}
		s[6] = &Point{(_x*2 + 40), (_y*3 + 40*2)}
		s[7] = &Point{(_x*3 + 40*2), (_y*3 + 40*2)}
	}
	if size == 9 {
		_x, _y = 3, 3
		s[0] = &Point{_x, _y}
		s[1] = &Point{_x*2 + 40, _y}
		s[2] = &Point{_x*3 + 40*2, _y}
		s[3] = &Point{_x, (_y*2 + 40)}
		s[4] = &Point{(_x*2 + 40), (_y*2 + 40)}
		s[5] = &Point{(_x*3 + 40*2), (_y*2 + 40)}
		s[6] = &Point{_x, (_y*3 + 40*2)}
		s[7] = &Point{(_x*2 + 40), (_y*3 + 40*2)}
		s[8] = &Point{(_x*3 + 40*2), (_y*3 + 40*2)}
	}
	return s
}

func getWidth(size int) int {
	var width int
	if size == 1 {
		width = 120
	}
	if size > 1 && size <= 4 {
		width = 60
	}
	if size >= 5 {
		width = 40
	}
	return width
}