package main
 
import (
    "fmt"
    "image"
    "image/color"
    "image/jpeg"
    "io/ioutil"
    "log"
    "os"
 
    "github.com/golang/freetype"
)
 
func main() {
    //需要加水印的图片
    imgfile, _ := os.Open("u=488179422,3251067872&fm=200&gp=0.jpg")
    defer imgfile.Close()
 
    jpgimg, _ := jpeg.Decode(imgfile)
 
    img := image.NewNRGBA(jpgimg.Bounds())
 
    for y := 0; y < img.Bounds().Dy(); y++ {
        for x := 0; x < img.Bounds().Dx(); x++ {
            img.Set(x, y, jpgimg.At(x, y))
        }
    }
    //拷贝一个字体文件到运行目录
    fontBytes, err := ioutil.ReadFile("simsun.ttc")
    if err != nil {
        log.Println(err)
    }
 
    font, err := freetype.ParseFont(fontBytes)
    if err != nil {
        log.Println(err)
    }
 
    f := freetype.NewContext()
    f.SetDPI(72)
    f.SetFont(font)
    f.SetFontSize(12)
    f.SetClip(jpgimg.Bounds())
    f.SetDst(img)
    f.SetSrc(image.NewUniform(color.RGBA{R: 255, G: 0, B: 0, A: 255}))
 
    pt := freetype.Pt(img.Bounds().Dx()-200, img.Bounds().Dy()-12)
    _, err = f.DrawString("中文 string 255.43,232.12312 老纪", pt)
 
    //draw.Draw(img,jpgimg.Bounds(),jpgimg,image.ZP,draw.Over)
 
    //保存到新文件中
    newfile, _ := os.Create("aaa.jpg")
    defer newfile.Close()
 
    err = jpeg.Encode(newfile, img, &jpeg.Options{100})
    if err != nil {
        fmt.Println(err)
    }
}