Golang golang-image2 (snippet)

Go programming example 'golang-image2'

golang-image2

Golang beginners example: golang-image2

package main

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

type Circle struct {
    X, Y, Radius float64
}

func (c *Circle) Brightness(x, y float64) uint8 {
    var dx, dy float64 = c.X - x, c.Y - y
    d := math.Sqrt(dx*dx+dy*dy) / c.Radius
    if d > 1 {
        return 0
    } else {
        return uint8((1 - math.Pow(d, 12)) * 255)
    }
}

func main() {
    var width, height int = 300, 300
    var hwidth, hheight float64 = float64(width / 2), float64(height / 2)
    var radius float64 = 42

    p := 2 * math.Pi / 3
    circleRed := &Circle{hwidth - radius*math.Sin(0), hheight - radius*math.Cos(0), 60}
    circleGreen := &Circle{hwidth - radius*math.Sin(p), hheight - radius*math.Cos(p), 60}
    circleBlue := &Circle{hwidth - radius*math.Sin(-p), hheight - radius*math.Cos(-p), 60}

    m := image.NewRGBA(image.Rect(0, 0, width, height))
    for x := 0; x < width; x++ {
        for y := 0; y < height; y++ {
            col := color.RGBA{
                circleRed.Brightness(float64(x), float64(y)),
                circleGreen.Brightness(float64(x), float64(y)),
                circleBlue.Brightness(float64(x), float64(y)),
                255,
            }
            m.Set(x, y, col)
        }
    }

    f, err := os.OpenFile("./images/rgb.png", os.O_WRONLY|os.O_CREATE, 0600)
    if err != nil {
        fmt.Println(err)
        return
    }
    defer f.Close()
    png.Encode(f, m)
}

Useful links

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