search
HomeBackend DevelopmentGolanggolang pdf convert image
golang pdf convert imageMay 14, 2023 pm 08:27 PM

With the advent of the digital age, the use of electronic documents is becoming more and more widespread, and PDF files are widely used in various scenarios, such as academic papers, contract agreements, electronic books, etc. However, in some cases, we need to convert PDF files to image format for subsequent processing or display. This article will introduce how to use Golang to convert PDF files to image format.

In order to realize the function of converting PDF to images, we need to use a third-party library GoPdf. GoPdf is a library for processing PDF files in the Go language. It supports generating and editing PDF files, and also supports converting PDF to image formats. The installation of GoPdf is very simple, just enter the following command in the terminal:

go get github.com/signintech/gopdf/...

After the installation is complete, we can start writing programs to convert PDF files into images. A sample program is given below:

package main

import (
    "bufio"
    "flag"
    "fmt"
    "github.com/signintech/gopdf"
    "image"
    "image/jpeg"
    "image/png"
    "os"
    "path/filepath"
    "strings"
)

var (
    inputFile        string // 输入的 PDF 文件名
    outputFilePrefix string // 输出的图片文件名前缀
    outputFormat     string // 输出的图片格式
    dpi              int    // 输出图片分辨率(DPI)
)

func main() {
    flag.StringVar(&inputFile, "input", "", "Input PDF filename")
    flag.StringVar(&outputFilePrefix, "prefix", "", "Output image filename prefix")
    flag.StringVar(&outputFormat, "format", "png", "Output image format: png or jpeg")
    flag.IntVar(&dpi, "dpi", 72, "Output image resolution (DPI)")
    flag.Parse()

    if inputFile == "" {
        fmt.Println("Please specify input PDF filename using -input")
        return
    }

    if outputFilePrefix == "" {
        outputFilePrefix = strings.TrimSuffix(inputFile, filepath.Ext(inputFile))
    }

    pdf, err := gopdf.Open(inputFile)
    if err != nil {
        fmt.Println("Failed to open PDF file:", err)
        return
    }
    defer pdf.Close()

    numPages := pdf.GetPageCount()
    if numPages == 0 {
        fmt.Println("PDF file contains no page")
        return
    }

    for i := 1; i <= numPages; i++ {
        page := pdf.GetPage(i)
        if page == nil {
            continue
        }
        defer page.Close()

        img := page.Render(dpi, dpi, nil)
        if img == nil {
            fmt.Println("Failed to render page", i)
            return
        }

        outputFile := fmt.Sprintf("%s_%d.%s", outputFilePrefix, i, outputFormat)
        file, err := os.Create(outputFile)
        if err != nil {
            fmt.Println("Failed to create output file:", err)
            return
        }
        defer file.Close()

        writer := bufio.NewWriter(file)
        if outputFormat == "png" {
            if err := png.Encode(writer, img); err != nil {
                fmt.Println("Failed to encode image:", err)
                return
            }
        } else {
            if err := jpeg.Encode(writer, img, &jpeg.Options{Quality: 95}); err != nil {
                fmt.Println("Failed to encode image:", err)
                return
            }
        }

        fmt.Println("Page", i, "saved to", outputFile)
    }

    fmt.Println("Done")
}

In this sample program, we specify the input PDF file name through the command line parameter -input, and -prefix specifies the output The image file name prefix, -format specifies the output image format, -dpi specifies the resolution (DPI) of the output image. If -prefix is not specified, the input file name minus the extension is used as the prefix by default. The program first opens the input PDF file and obtains the total number of pages in it. Then iterate through each page, render it as a picture, and save it to the output file. The image format can be PNG or JPEG, which are encoded using image/png and image/jpeg respectively in the Go standard library.

Using the sample program is very simple, just enter the following command in the terminal:

go run pdf2img.go -input input.pdf

where input.pdf is the name of the PDF file to be converted. If you need to specify the prefix, format or resolution of the output file, you can add the corresponding command line parameters, for example:

go run pdf2img.go -input input.pdf -prefix output -format jpeg -dpi 300

This will convert input.pdf into a JPEG format image, The resolution is 300 DPI and saved with names such as output_1.jpeg, output_2.jpeg, output_3.jpeg, etc.

To sum up, using GoPdf and image/png and image/jpeg in the Go standard library can easily convert PDF files to image formats , to implement your own PDF processing needs.

The above is the detailed content of golang pdf convert image. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Go language pack import: What is the difference between underscore and without underscore?Go language pack import: What is the difference between underscore and without underscore?Mar 03, 2025 pm 05:17 PM

This article explains Go's package import mechanisms: named imports (e.g., import "fmt") and blank imports (e.g., import _ "fmt"). Named imports make package contents accessible, while blank imports only execute t

How to convert MySQL query result List into a custom structure slice in Go language?How to convert MySQL query result List into a custom structure slice in Go language?Mar 03, 2025 pm 05:18 PM

This article details efficient conversion of MySQL query results into Go struct slices. It emphasizes using database/sql's Scan method for optimal performance, avoiding manual parsing. Best practices for struct field mapping using db tags and robus

How to implement short-term information transfer between pages in the Beego framework?How to implement short-term information transfer between pages in the Beego framework?Mar 03, 2025 pm 05:22 PM

This article explains Beego's NewFlash() function for inter-page data transfer in web applications. It focuses on using NewFlash() to display temporary messages (success, error, warning) between controllers, leveraging the session mechanism. Limita

How can I define custom type constraints for generics in Go?How can I define custom type constraints for generics in Go?Mar 10, 2025 pm 03:20 PM

This article explores Go's custom type constraints for generics. It details how interfaces define minimum type requirements for generic functions, improving type safety and code reusability. The article also discusses limitations and best practices

How do I write mock objects and stubs for testing in Go?How do I write mock objects and stubs for testing in Go?Mar 10, 2025 pm 05:38 PM

This article demonstrates creating mocks and stubs in Go for unit testing. It emphasizes using interfaces, provides examples of mock implementations, and discusses best practices like keeping mocks focused and using assertion libraries. The articl

How to write files in Go language conveniently?How to write files in Go language conveniently?Mar 03, 2025 pm 05:15 PM

This article details efficient file writing in Go, comparing os.WriteFile (suitable for small files) with os.OpenFile and buffered writes (optimal for large files). It emphasizes robust error handling, using defer, and checking for specific errors.

How do you write unit tests in Go?How do you write unit tests in Go?Mar 21, 2025 pm 06:34 PM

The article discusses writing unit tests in Go, covering best practices, mocking techniques, and tools for efficient test management.

How can I use tracing tools to understand the execution flow of my Go applications?How can I use tracing tools to understand the execution flow of my Go applications?Mar 10, 2025 pm 05:36 PM

This article explores using tracing tools to analyze Go application execution flow. It discusses manual and automatic instrumentation techniques, comparing tools like Jaeger, Zipkin, and OpenTelemetry, and highlighting effective data visualization

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment