Golang golang-image (snippet)

Go programming example 'golang-image'

golang-image

Golang beginners example: golang-image

package main

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

type ImageSet interface {
    Set(x, y int, c color.Color)
}

func main() {
    file, err := os.Open("./images/selfcss.png")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    img, err := png.Decode(file)
    if err != nil {
        log.Fatal(os.Stderr, "%s: %v\n", "./images/selfcss.png", err)
    }

    b := img.Bounds()

    imgSet := img.(ImageSet)
    for y := b.Min.Y; y < b.Max.Y; y++ {
        for x := b.Min.X; x < b.Max.X; x++ {
            oldPixel := img.At(x, y)
            r, g, b, a := oldPixel.RGBA()
            fmt.Println(r, g, b, a)
            pixel := color.RGBA{uint8(g), uint8(g), uint8(g), uint8(a)}
            imgSet.Set(x, y, pixel)
        }
    }

    fd, err := os.Create("./images/gray.png")
    if err != nil {
        log.Fatal(err)
    }

    err = png.Encode(fd, img)
    if err != nil {
        log.Fatal(err)
    }

    err = fd.Close()
    if err != nil {
        log.Fatal(err)
    }

    file, err = os.Open("./images/selfcss.png")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    img, err = png.Decode(file)
    if err != nil {
        log.Fatal(os.Stderr, "%s: %v\n", "./images/selfcss.png", err)
    }

    b = img.Bounds()

    imgSet = img.(ImageSet)
    for y := b.Min.Y; y < b.Max.Y; y++ {
        for x := b.Min.X; x < b.Max.X; x++ {
            oldPixel := img.At(x, y)
            r, g, b, a := oldPixel.RGBA()
            //fmt.Println(r, g, b, a)
            r = 65535 - r
            g = 65535 - g
            b = 65535 - b
            pixel := color.RGBA{uint8(r), uint8(g), uint8(b), uint8(a)}
            imgSet.Set(x, y, pixel)
        }
    }

    fd, err = os.Create("./images/inv.png")
    if err != nil {
        log.Fatal(err)
    }

    err = png.Encode(fd, img)
    if err != nil {
        log.Fatal(err)
    }

    err = fd.Close()
    if err != nil {
        log.Fatal(err)
    }
}

Useful links

• Learn Go: https://golangr.com
• Download Go: https://golang.org