go语言实现图像切割
package main
import (
"errors"
"fmt"
"golang.org/x/image/bmp"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"log"
"os"
"strings"
"github.com/nfnt/resize"
)
func main() {
src := "C:\\Users\\wg\\go\\src\\学习go语言\\预处理\\家人们.png"//"png.png" 文件名
dst := strings.Replace(src, ".", "_aa.", 1)
fmt.Println("src=", src, " dst=", dst)
fIn, _ := os.Open(src)
defer fIn.Close()
fOut, _ := os.Create(dst)
defer fOut.Close()
err := Clip(fIn, fOut, 0,0, 0, 0, 150, 150, 100)
if err != nil {
panic(err)
}
/* w, h, err := Scale(fIn, fOut, 150, 150, 100)
if err != nil {
panic(err)
}
fmt.Println(w, h)*/
}
//补上缺失的代码
//* Clip 图片裁剪
//* 入参:图片输入、输出、缩略图宽、缩略图高、Rectangle{Pt(x0, y0), Pt(x1, y1)}，精度
//* 规则:如果精度为0则精度保持不变
//*
//* 返回:error
// */
func Clip(in io.Reader, out io.Writer, wi, hi, x0, y0, x1, y1, quality int) (err error) {
err = errors.New("unknow error")
defer func() {
if r := recover(); r != nil {
log.Println(r)
}
}()
var origin image.Image
var fm string
origin, fm, err = image.Decode(in)
if err != nil {
log.Println(err)
return err
}
if wi == 0 || hi == 0 {
wi = origin.Bounds().Max.X
hi = origin.Bounds().Max.Y
}
var canvas image.Image
if wi != origin.Bounds().Max.X {
//先缩略
canvas = resize.Thumbnail(uint(wi), uint(hi), origin, resize.Lanczos3)
} else {
canvas = origin
}
switch fm {
case "jpeg":
img := canvas.(*image.YCbCr)
subImg := img.SubImage(image.Rect(x0, y0, x1, y1)).(*image.YCbCr)
return jpeg.Encode(out, subImg, &jpeg.Options{quality})
case "png":
switch canvas.(type) {
case *image.NRGBA:
img := canvas.(*image.NRGBA)
subImg := img.SubImage(image.Rect(x0, y0, x1, y1)).(*image.NRGBA)
return png.Encode(out, subImg)
case *image.RGBA:
img := canvas.(*image.RGBA)
subImg := img.SubImage(image.Rect(x0, y0, x1, y1)).(*image.RGBA)
return png.Encode(out, subImg)
}
case "gif":
img := canvas.(*image.Paletted)
subImg := img.SubImage(image.Rect(x0, y0, x1, y1)).(*image.Paletted)
return gif.Encode(out, subImg, &gif.Options{})
case "bmp":
img := canvas.(*image.RGBA)
subImg := img.SubImage(image.Rect(x0, y0, x1, y1)).(*image.RGBA)
return bmp.Encode(out, subImg)
default:
return errors.New("ERROR FORMAT")
}
return nil
}