Golang image.NRGBA(64).SubImage function example

package image

 func (p *NRGBA) SubImage(r Rectangle) Image
  

SubImage returns an image representing the portion of the image p visible through r. The returned value shares pixels with the original image.

Golang image.NRGBA(64).SubImage function usage example

 package main

 import (
 "fmt"
 "image"
 "image/png"
 "os"
 )

 func init() {
 // without this register .. At(), Bounds() functions will
 // caused memory pointer error!!
 image.RegisterFormat("png", "png", png.Decode, png.DecodeConfig)
 }

 func main() {
 imgfile, err := os.Open("./img.png")

 if err != nil {
 fmt.Println("img.png file not found!")
 os.Exit(1)
 }

 defer imgfile.Close()

 img, _, err := image.Decode(imgfile)

 bounds := img.Bounds()

 nrgba := image.NewNRGBA(bounds)

 rect := image.Rect(0, 0, 100, 100)

 subimg := nrgba.SubImage(rect)

 fmt.Println(subimg.Bounds())
 fmt.Println(subimg.At(10, 10))
 }

Reference :

http://golang.org/pkg/image/#NRGBA.SubImage