How to merge multiple images into one image using Golang

How to use Golang to merge multiple pictures into one picture

In many application scenarios, we need to merge multiple pictures into one picture, such as photo album production, Image processing, etc. This article will introduce how to use Golang language to implement this function.

First, we need to import Golang’s image processing package image and image/jpeg or image/png. We also need to import the os module to read and save image files.

Code example:

package main

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

func main() {
    // 读取图片文件
    imgFiles := []string{"image1.jpg", "image2.jpg", "image3.jpg"}

    // 创建一个画布，大小为合并后的图片大小
    totalWidth := 0
    totalHeight := 0
    images := make([]image.Image, len(imgFiles))

    for i, file := range imgFiles {
        // 打开图像文件
        f, err := os.Open(file)
        if err != nil {
            log.Fatal(err)
        }
        defer f.Close()

        // 读取图像文件
        img, format, err := image.Decode(f)
        if err != nil {
            log.Fatal(err)
        }

        images[i] = img

        // 累计图片宽度和高度
        totalWidth += img.Bounds().Dx()
        if img.Bounds().Dy() > totalHeight {
            totalHeight = img.Bounds().Dy()
        }
    }

    // 创建一个画布，大小为所有图片的宽度之和和其中最高的一张图片的高度
    result := image.NewRGBA(image.Rect(0, 0, totalWidth, totalHeight))

    // 将图片绘制到画布上
    offsetX := 0

    for _, img := range images {
        // 计算图片在画布上的位置
        r := image.Rect(offsetX, 0, offsetX+img.Bounds().Dx(), img.Bounds().Dy())

        // 绘制图片
        draw.Draw(result, r, img, img.Bounds().Min, draw.Src)

        // 更新下一张图片的位置
        offsetX += img.Bounds().Dx()
    }

    // 保存合并后的图片
    outFile, err := os.Create("merged.jpg")
    if err != nil {
        log.Fatal(err)
    }
    defer outFile.Close()

    // 使用jpeg格式保存图片
    err = jpeg.Encode(outFile, result, &jpeg.Options{Quality: 100})
    if err != nil {
        log.Fatal(err)
    }
}

In the above code, we first define a string slice imgFiles to store the image file names to be merged. In the main function, we traverse imgFiles, opening, reading and drawing each image in turn.

We read the image file through the image.Decode function. The decoded img object represents all the pixel information of an image. Use the img.Bounds method to get the width and height of the image. We add up the width and height of each image to calculate the size of the merged image.

After that, we use the image.NewRGBA function to create a new RGBA format canvas result. The width is the sum of the widths of all pictures, and the height is the tallest among them. The height of an image. We then use the draw.Draw function to draw each image onto the canvas. By calculating the position and offset of each image, we can draw the image to the correct location.

Finally, we use the jpeg.Encode function to save the merged image to a file.

It should be noted that the above code only provides examples for jpeg format. If you need to process images in other common formats such as png, you only need to modify the imported image processing package and the format of the saved image.

Through the above examples, we learned how to use Golang to merge multiple pictures into one picture. This technology can be widely used in photo album production, image processing, web page generation and other scenarios, and has great practicality and application value.

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