An answer of the exercise: Slices on a tour of Go

answer_pic.go

package main

import "code.google.com/p/go-tour/pic"

func Pic(dx, dy int) [][]uint8 {
	// Allocate two-dimensioanl array.
	a := make([][]uint8, dy)
	for i := 0; i < dy; i++ {
		a[i] = make([]uint8, dx)
	}
	
	// Do something.
	for i := 0; i < dy; i++ {
		for j := 0; j < dx; j++ {
			switch {
			case j % 15 == 0:
				a[i][j] = 240
			case j % 3 == 0:
				a[i][j] = 120
			case j % 5 == 0:
				a[i][j] = 150
			default:
				a[i][j] = 100
			}
		}
	}	
	return a
}

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

package main

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

func pointValue1(x, y int) uint8 {
	return uint8((x + y) / 2)
}

func pointValue2(x, y int) uint8 {
	return uint8(x * y)
}

func pointValue3(x, y int) uint8 {
	return uint8(x ^ y)
}

func Pic(dx, dy int) [][]uint8 {
	// initialize slice rows with dy length
	var matrix [][]uint8
	
	// initialize the i'th element of rows with dx length slice
	for i := 0; i < dy; i ++ {
		// var array_rows [dx]uint8
		var array_rows []uint8
		// update the value of each point
		for j := 0; j < dx; j ++ {
			// array_rows[j] = pointValue1(i, j)
			array_rows = append(array_rows, pointValue3(i, j))
		}
		// matrix = append(matrix, array_rows[0:])
		matrix = append(matrix, array_rows)
	}
	
	// fmt.Println(matrix)
	return matrix
}

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

package main

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

func Pic(dx, dy int) [][]uint8 {
	result := make([][]uint8, dy)
	for y := range result {
		result[y] = make([]uint8, dx)
		for x := range result[y] {
			result[y][x] = uint8((x + y) / 2)
		}
	}
	return result
}

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

package main

import (
	"math"

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

func Pic(dx, dy int) [][]uint8 {
	pic := make([][]uint8, dy, dy)

	for y := range pic {
		pic[y] = make([]uint8, dx)

		for x := range pic[y] {
			pic[y][x] = uint8(float64(x^y-y^x) / math.Pi)
		}
	}

	return pic
}

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

package main

import (
	"math"

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

func Pic(dx, dy int) [][]uint8 {
	pic := make([][]uint8, dy, dy)
	i := 10
	for y := range pic {
		pic[y] = make([]uint8, dx)

		for x := range pic[y] {

			i++
			pic[y][x] = uint8(float64((x+y)*i) / math.Pi)
		}
	}

	return pic
}

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

package main

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

func Pic(dx, dy int) [][]uint8 {
	var image [][]uint8

	for y := 0; y < dy; y++ {
		var row []uint8

		for x := 0; x < dx; x++ {
			row = append(row, uint8(x*10 + y*100))
		}

		image = append(image, row)
	}

	return image
}

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

 package main

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

 func Pic(dx, dy int) [][]uint8 {

 slice:= make([][]uint8, dy, dy)
 for y, _ := range slice {
	slice[y] = make([]uint8, dx)
	for x:= range slice {
		i := uint8(y)
		j := uint8(x)
		slice[i][j] = (j * j * 100) + (i * i * 100)
	}
}
 return slice
} 
func main() {
      pic.Show(Pic)
}

package main

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

func Pic(dx, dy int) [][]uint8 {
    bitmap := make([][]uint8, dy)
    
    for i := 0; i < dy; i++ {
	bitmap[i] = make([]uint8, dx)
    }
	
    for i := 0; i < dy; i++ {
	for j := 0; j < dx; j++ {
	    bitmap[i][j] = uint8(math.Sqrt(float64(i)) * .01 * float64(i * j)) >> 2
	}
    }
	
    return bitmap
}

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

package main

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

func Pic(dx, dy int) [][]uint8 {
	img := make([][]uint8, dy)
	
	for y := range dy {
		row := make([]uint8, dx)
		for x := range dx {
			row[x] = uint8(x * y)
		}
		img[y] = row
	}
	
	return img
}

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