golang实现图片水印效果

//golang图片式水印处理
//未实现Web上传等代码...
//sam
//2013.6.19
//http://zituo.net
package main
 
import (
    "fmt"
    "image"
    "image/draw"
    "image/jpeg"
    "image/png"
    "os"
)
 
func main() {
    //原始图片是sam.jpg
    imgb,_ := os.Open("sam.jpg")
    img,_ := jpeg.Decode(imgb)
    defer imgb.Close()
 
    wmb,_ := os.Open("text.png")
    watermark,_ := png.Decode(wmb)
    defer wmb.Close()
 
    //把水印写到右下角，并向0坐标各偏移10个像素
    offset := image.Pt(img.Bounds().Dx()-watermark.Bounds().Dx()-10,img.Bounds().Dy()-watermark.Bounds().Dy()-10)
    b := img.Bounds()
    m := image.NewNRGBA(b)
 
    draw.Draw(m,b,img,image.ZP,draw.Src)
    draw.Draw(m,watermark.Bounds().Add(offset),watermark,draw.Over)
 
    //生成新图片new.jpg，并设置图片质量..
    imgw,_ := os.Create("new.jpg")
    jpeg.Encode(imgw,m,&jpeg.Options{100})
 
    defer imgw.Close()
 
    fmt.Println("水印添加结束,请查看new.jpg图片...")
}