Step by Step solution about How to resolve the algorithm Draw a pixel step by step in the Go programming language

This Go program demonstrates basic image manipulation by creating an image with a green background and setting the color of a specific pixel to red. Here's how it works:

1. package main: Specifies that this is the main package of the program.

2. import statements: Import necessary packages for image manipulation.

   • image: Provides the core image types and operations.
   • image/color: Defines color types and constants.
   • image/draw: Contains functions for drawing and compositing images.

3. main function: This is the entry point of the program.

4. Creating the Image:

   • rect := image.Rect(0, 0, 320, 240): Defines the dimensions of the image. It creates a rectangle from point (0, 0) to point (320, 240), resulting in a 320x240 pixel image.
   • img := image.NewRGBA(rect): Creates a new RGBA (Red, Green, Blue, Alpha) image with the specified rectangle as its bounds. Each pixel in the image has four components: red, green, blue, and alpha (transparency).

5. Setting the Background Color:

   • green := color.RGBA{0, 255, 0, 255}: Defines a green color using the RGBA type. Each component value ranges from 0 to 255, where 0 represents the minimum intensity and 255 represents the maximum intensity.
   • draw.Draw(img, rect, &image.Uniform{green}, image.ZP, draw.Src): Fills the entire image with the specified green color.
     • image.ZP: Represents the zero point (0, 0) in the image.
     • draw.Src: Indicates that the source color should be used without any blending or modification.

6. Setting a Single Pixel Color:

   • red := color.RGBA{255, 0, 0, 255}: Defines a red color using the RGBA type.
   • img.Set(100, 100, red): Sets the color of the pixel at coordinates (100, 100) to red.

7. Checking the Color of a Pixel:

   • c1 := img.At(0, 0): Obtains the color of the pixel at (0, 0).
   • c2 := img.At(100, 100): Obtains the color of the pixel at (100, 100).

8. Creating a Color Map for Output:

   • cmap := map[color.Color]string{green: "green", red: "red"}: Creates a map that maps colors (green and red) to their corresponding names.

9. Printing the Pixel Colors:

   • fmt.Println("The color of the pixel at ( 0, 0) is", cmap[c1], "\b."): Prints the color of the pixel at (0, 0) using the color map.
   • fmt.Println("The color of the pixel at (100, 100) is", cmap[c2], "\b."): Prints the color of the pixel at (100, 100) using the color map.

When you run this program, it will create an image with a green background and a single red pixel at (100, 100). It then prints a message indicating that the pixel at (0, 0) is green and the pixel at (100, 100) is red.

package main

import (
    "fmt"
    "image"
    "image/color"
    "image/draw"
)

func main() {
    rect := image.Rect(0, 0, 320, 240)
    img := image.NewRGBA(rect)

    // Use green background, say.
    green := color.RGBA{0, 255, 0, 255}
    draw.Draw(img, rect, &image.Uniform{green}, image.ZP, draw.Src)

    // Set color of pixel at (100, 100) to red
    red := color.RGBA{255, 0, 0, 255}
    img.Set(100, 100, red)

    // Check it worked.
    cmap := map[color.Color]string{green: "green", red: "red"}
    c1 := img.At(0, 0)
    c2 := img.At(100, 100)
    fmt.Println("The color of the pixel at (  0,   0) is", cmap[c1], "\b.")
    fmt.Println("The color of the pixel at (100, 100) is", cmap[c2], "\b.")
}