微信头像

复制from PIL import Image, ImageDraw

# 打开图片并转为 RGBA（支持透明背景）
img = Image.open("input.jpg").convert("RGBA")

# 创建圆形遮罩
mask = Image.new("L", img.size, 0)
draw = ImageDraw.Draw(mask)
width, height = img.size
radius = min(width, height) // 2
draw.ellipse(
    [(width - radius * 2) // 2, (height - radius * 2) // 2,
     (width + radius * 2) // 2, (height + radius * 2) // 2],
    fill=255
)

# 应用遮罩，透明背景
result = Image.new("RGBA", img.size, (0, 0, 0, 0))
result.paste(img, (0, 0), mask)
result.save("avatar_circle.png")
print("已生成圆形头像：avatar_circle.png")

复制package main

import (
	"image"
	"image/color"
	"image/draw"
	"image/jpeg"
	"image/png"
	"log"
	"math"
	"os"
)

func main() {
	// 打开图片
	file, err := os.Open("input.jpg")
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	src, err := jpeg.Decode(file)
	if err != nil {
		log.Fatal(err)
	}

	bounds := src.Bounds()
	width, height := bounds.Dx(), bounds.Dy()
	radius := int(math.Min(float64(width), float64(height))) / 2
	cx, cy := width/2, height/2

	// 创建圆形遮罩
	mask := image.NewAlpha(bounds)
	for y := 0; y < height; y++ {
		for x := 0; x < width; x++ {
			dx, dy := x-cx, y-cy
			dist := math.Sqrt(float64(dx*dx + dy*dy))
			if dist <= float64(radius) {
				mask.SetAlpha(x, y, color.Alpha{A: 255})
			}
		}
	}

	// 合成透明背景
	dst := image.NewNRGBA(bounds)
	draw.DrawMask(dst, bounds, src, image.Point{}, mask, image.Point{}, draw.Over)

	out, _ := os.Create("avatar_circle.png")
	defer out.Close()
	png.Encode(out, dst)
	println("已生成圆形头像：avatar_circle.png")
}

复制// 在浏览器中运行（需要 <input type="file" id="fileInput"> 和 <canvas id="canvas">）
const fileInput = document.getElementById('fileInput');
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

fileInput.addEventListener('change', (e) => {
  const file = e.target.files[0];
  if (!file) return;

  const img = new Image();
  img.onload = () => {
    const size = Math.min(img.width, img.height);
    canvas.width = size;
    canvas.height = size;

    // 绘制圆形裁剪
    ctx.beginPath();
    ctx.arc(size / 2, size / 2, size / 2, 0, Math.PI * 2);
    ctx.closePath();
    ctx.clip();

    // 居中绘制原图
    ctx.drawImage(img, (size - img.width) / 2, (size - img.height) / 2);

    // 导出为 PNG（透明背景）
    const link = document.createElement('a');
    link.download = 'avatar_circle.png';
    link.href = canvas.toDataURL('image/png');
    link.click();
  };
  img.src = URL.createObjectURL(file);
});