golang 按照曲线裁剪图片

要按曲线裁剪图片，您可以使用golang中的图像处理库。下面是一个示例代码，它可以读取图像并将其按照指定的曲线裁剪：

package main

import (
    "fmt"
    "image"
    "image/color"
    "image/draw"
    "image/jpeg"
    "math"
    "os"
)

type Curve struct {
    A, B, C float64
}

func (curve Curve) interpolate(x float64) float64 {
    return curve.A*math.Pow(x, 2) + curve.B*x + curve.C
}

func main() {
    file, err := os.Open("input.jpg")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer file.Close()

    img, err := jpeg.Decode(file)
    if err != nil {
        fmt.Println(err)
        return
    }

    width := img.Bounds().Max.X
    height := img.Bounds().Max.Y

    // create a black mask with the same dimensions as the image
    mask := image.NewGray(image.Rect(0, 0, width, height))
    draw.Draw(mask, mask.Bounds(), image.Black, image.ZP, draw.Src)

    // create a curve to use for the clipping path
    curve := Curve{0.01, -0.1, 1}

    // loop over each pixel in the image and set its alpha based on the curve
    for x := 0; x < width; x++ {
        for y := 0; y < height; y++ {
            // calculate the distance of the current pixel from the curve
            distance := float64(y) - curve.interpolate(float64(x))

            // set the alpha of the pixel based on the distance from the curve
            alpha := uint8(math.Max(0, math.Min(255, 255-(100*distance*distance))))
            mask.SetGray(x, y, color.Gray{alpha})
        }
    }

    // create a new image by applying the mask to the original image
    newImg := image.NewRGBA(img.Bounds())
    draw.DrawMask(newImg, newImg.Bounds(), img, image.ZP, mask, image.ZP, draw.Over)

    // save the new image to a file
    out, err := os.Create("output.jpg")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer out.Close()

    jpeg.Encode(out, newImg, nil)
}

这个示例代码使用了一个二次曲线来裁剪图像，您可以根据需要修改曲线的参数。请注意，这个示例代码只是一个简单的示例，您可以根据需要进行修改和优化