How to convert picture to black and white and halftone effect using Golang

How to use Golang to convert pictures to black and white and halftone effects

With the continuous development of technology, image processing has become an increasingly important field. In image processing, converting color pictures into black and white or halftone effects is a common operation. This article will introduce how to use the Golang programming language to convert pictures into black and white and halftone effects.

First, we need to import the necessary packages. In Golang, you can use the image and image/color packages to perform image processing operations. The code is as follows:

package main

import (
    "image"
    "image/color"
    "image/jpeg"
    "log"
    "os"
)

Next, we can define a function to read the image file. The code is as follows:

func loadImage(filename string) (image.Image, error) {
    file, err := os.Open(filename)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    img, err := jpeg.Decode(file)
    if err != nil {
        return nil, err
    }

    return img, nil
}

Then, we can define a function to convert the color picture to black and white effect. This can be achieved by processing each pixel of the image. The code is as follows:

func toGrayscale(img image.Image) *image.Gray {
    bounds := img.Bounds()
    gray := image.NewGray(bounds)

    for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
        for x := bounds.Min.X; x < bounds.Max.X; x++ {
            oldColor := img.At(x, y)
            grayColor := color.GrayModel.Convert(oldColor)
            gray.Set(x, y, grayColor)
        }
    }

    return gray
}

Next, we can define a function to convert the color picture into a halftone effect. The halftone effect can be achieved by processing each pixel of the image and converting it into a limited set of color values. The code is as follows:

func toHalftone(img image.Image) *image.Gray16 {
    bounds := img.Bounds()
    halftone := image.NewGray16(bounds)

    for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
        for x := bounds.Min.X; x < bounds.Max.X; x++ {
            oldColor := img.At(x, y)
            halftoneColor := color.Gray16Model.Convert(oldColor)
            halftone.Set(x, y, halftoneColor)
        }
    }

    return halftone
}

Finally, we can define a function to save the converted image. The code is as follows:

func saveImage(img image.Image, filename string) error {
    file, err := os.Create(filename)
    if err != nil {
        return err
    }
    defer file.Close()

    err = jpeg.Encode(file, img, nil)
    if err != nil {
        return err
    }

    return nil
}

Now, we can write a main function to call the above function and test it. The code is as follows:

func main() {
    // 读取图片文件
    img, err := loadImage("input.jpg")
    if err != nil {
        log.Fatal(err)
    }

    // 转换为黑白效果
    gray := toGrayscale(img)
    err = saveImage(gray, "output_gray.jpg")
    if err != nil {
        log.Fatal(err)
    }

    // 转换为半色调效果
    halftone := toHalftone(img)
    err = saveImage(halftone, "output_halftone.jpg")
    if err != nil {
        log.Fatal(err)
    }

    log.Println("图片转换完成")
}

By running the above code, we can convert the input image file to black and white and halftone effects, and save it as output_gray.jpg and output_halftone.jpg files.

The above is how to use Golang to convert pictures into black and white and halftone effects. With these simple code examples, we can easily implement image processing functions in Golang. Hope this article is helpful to you!

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