Learn go language 0x04: Code of exercises sliced in go language journey

* Exercises ： operation slice display picture

Exercise location ： https://tour.go-zh.org/moretypes/18

practice ： section
Realization Pic. It should return a length of dy The section of , Each of these elements is a length of dx, Element type is uint8 The section of . When you run this program , It interprets each integer as a grayscale value （ ok , It's actually the blue value ） And display its corresponding image .

The choice of image is up to you . Several interesting functions include (x+y)/2, xy, x^y, xlog(y) and x%(y+1).

（ Tips ： You need to use a loop to allocate [][]uint8 Each of the []uint8; Please use uint8(intValue) Convert between types ; You may use math Functions in packages .）

* Code

package main

import "golang.org/x/tour/pic"

func Pic(dx, dy int) [][]uint8 {
    
    img := make([][]uint8, dy)
    for i := 0; i < dx; i++ {
    
        img[i] = make([]uint8, dx)
    }
    for i := 0; i < dy; i++ {
    
        for j := 0; j < dx; j++ {
    
            img[i][j] = (uint8)((i+j)/2)
        }
    }
    return img
}

func main() {
    
    pic.Show(Pic)
}

Run on website , The display effect is ：

If you run it on the command line , The result is ：
notes ： I am here cygwin Running in .

$ ./slice02.exe
IMAGE:iVBORw0KGgoAAAANSUhEUgAAAQAAAAEACAIAAADTED8xAAADKElEQVR4nOzVoRHAMAzAQCfX/VduxjDQk8di+mb+mTlnyKB3vYBc9K4XkIs6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANO+AAAA//9hKgMPVczXbQAAAABJRU5ErkJggg==

On the base64 decode , You can get pictures ：

$ echo -n "iVBORw0KGgoAAAANSUhEUgAAAQAAAAEACAIAAADTED8xAAADKElEQVR4nOzVoRHAMAzAQCfX/VduxjDQk8di+mb+mTlnyKB3vYBc9K4XkIs6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANM6ANO+AAAA//9hKgMPVczXbQAAAABJRU5ErkJggg==" | base64.exe -d > pic.png

• (i+j)/2 According to the effect ：
  

• i*j Display effect of ：
  

• i^j The effect of ：
  

• i*log（y） The effect of ：
  
  i*log（y）, The code needs to be changed like this ：

package main

import "golang.org/x/tour/pic"
import "math"

func Pic(dx, dy int) [][]uint8 {
    
	img := make([][]uint8, dy)
	for i := 0; i < dy; i++ {
    
		img[i] = make([]uint8, dx)
	}
	for i := 0; i < dy; i++ {
    
		for j := 0; j < dx; j++ {
    
			img[i][j] = (uint8)(i*int(math.Log(float64(j))))
		}
	}
	return img
}

func main() {
    
	pic.Show(Pic)
}

• i%(j+1) The effect of ：