Golang image.DecodeConfig function example

package image
 func DecodeConfig(r io.Reader) (Config, string, error)
  
DecodeConfig decodes the color model and dimensions of an image that has been encoded in a registered format. The string returned is the format name used during format registration. Format registration is typically done by an init function in the codec-specific package.

Golang image.DecodeConfig function usage example

 package main

 import (
 "fmt"
 "image"
 "image/png"
 "io/ioutil"
 "os"
 "bytes"
 )

 func init() {
 image.RegisterFormat("png", "png", png.Decode, png.DecodeConfig)
 }

 func main() {
 imgBuffer, err := ioutil.ReadFile("./img.png")

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

 reader := bytes.NewReader(imgBuffer)

 iconf, formatname, err := image.DecodeConfig(reader)

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }

 //test

 fmt.Println("Format : ", formatname)

 fmt.Println("Width : ", iconf.Width)

 fmt.Println("Height : ", iconf.Height)

 fmt.Println("ColorModel : ", iconf.ColorModel)

 }

Sample output (depending on image file ) :