NodeJSでPDFを画像に変換する方法

前提条件

First, make sure you have Node.js and npm (Node Package Manager) installed on your machine. You can check Node installations by running the following commands in your command prompt (cmd):

node --version
npm --version

node --version
npm --version

If it is not installed, you will need to download it from the Node.js website.

プロジェクトの設定

To get started, create a new directory for your project. For this tutorial, let's name this directory NodeJS_PDFtoImage. Next, navigate to it in the command prompt and initialize a new Node.js project by running:

npm init -y

npm init -y

Running the above command will produce a package.json file that will allow us to install our project's required dependencies.

npm install pdf-poppler

npm install pdf-poppler

Converting PDF to Image File

Once the installation is complete, create a new file in our project's root directory and name it pdfToImage.js. Open the file in your preferred text editor, and add the required modules:

const pdfPoppler = require('pdf-poppler');

A sample 28-page PDF file is shown below.

Next, define a function called convertPdfToImage that takes in the path to the PDF file (pdfPath) and the output directory path (outputPath). This function will convert our sample PDF document into images.

async function convertPdfToImage(pdfPath, outputPath) {
  const options = {
    format: 'jpeg',  // You can choose other formats like png or tiff
    out_dir: outputPath,
    out_prefix: 'page',
    page: null  // Specify the page number here to convert a specific page, otherwise null to convert all pages
  };

  try {
    await pdfPoppler.convert(pdfPath, options);
    console.log('PDF converted to image successfully!');
  } catch (error) {
    console.error('Error converting PDF to image:', error);
  }
}

The function uses the pdf-poppler package to convert the PDF to JPEG image format. We set the format option to 'jpeg' in this case, but you can choose other formats such as 'png' or 'tiff'. The out_dir option specifies the directory where the output images will be saved, and out_prefix sets a prefix for the output image files. The page option allows you to specify a particular page to convert, or you can leave it as null to convert all pages.

To convert a PDF file to images, you can call the convertPdfToImage function with the appropriate file paths. 例えば：

const pdfPath = '/path/to/input.pdf';
const outputPath = '/path/to/output/folder';

convertPdfToImage(pdfPath, outputPath);

Note: Replace pdfPath value "/path/to/input.pdf" with the actual path to the input PDF file and "/path/to/output/folder" with the desired output directory path.

完全なコードは次のとおりです。

const pdfPoppler = require('pdf-poppler');

const pdfPath = 'C:\\Users\\hp\\Desktop\\NodeJS_PDFtoImage\\pdf_files\\input.pdf';
const outputDir = 'C:\\Users\\hp\\Desktop\\NodeJS_PDFtoImage\\pdf_images';

async function convertPdfToImage(pdfPath, outputPath) {
  const opts = {
    format: 'jpeg',      // You can choose other formats like png or tiff
    out_dir: outputPath,
    out_prefix: 'page',
    page: null           // Specify the page number here to convert a specific page, otherwise null to convert all pages
  };

  try {
    await pdfPoppler.convert(pdfPath, opts);
    console.log('PDF converted to image successfully!');
  } catch (error) {
    console.error('Error converting PDF to image:', error);
  }
}

convertPdfToImage(pdfPath, outputDir);

Execute the Node.js Script

Run the Node.js script by executing the following command:

node pdfToImage.js

node pdfToImage.js

This will run the Node.js script and convert the PDF to image files using pdf-poppler.

Rasterize PDF File to Image in C#

using IronPdf;
using IronSoftware.Drawing;

var pdf = PdfDocument.FromFile("input.pdf");

// Extract all pages to a folder as image files
pdf.RasterizeToImageFiles(@"C:\image\folder\*.png");

// Dimensions and page ranges may be specified
pdf.RasterizeToImageFiles(@"C:\image\folder\example_pdf_image_*.jpg", 100, 80);

// Extract all pages as AnyBitmap objects
AnyBitmap [] pdfBitmaps = pdf.ToBitmap();

using IronPdf;
using IronSoftware.Drawing;

var pdf = PdfDocument.FromFile("input.pdf");

// Extract all pages to a folder as image files
pdf.RasterizeToImageFiles(@"C:\image\folder\*.png");

// Dimensions and page ranges may be specified
pdf.RasterizeToImageFiles(@"C:\image\folder\example_pdf_image_*.jpg", 100, 80);

// Extract all pages as AnyBitmap objects
AnyBitmap [] pdfBitmaps = pdf.ToBitmap();

Imports IronPdf
Imports IronSoftware.Drawing

Private pdf = PdfDocument.FromFile("input.pdf")

' Extract all pages to a folder as image files
pdf.RasterizeToImageFiles("C:\image\folder\*.png")

' Dimensions and page ranges may be specified
pdf.RasterizeToImageFiles("C:\image\folder\example_pdf_image_*.jpg", 100, 80)

' Extract all pages as AnyBitmap objects
Dim pdfBitmaps() As AnyBitmap = pdf.ToBitmap()

結論

In this article, we explored how to convert PDF files to images in Node.js using the pdf-poppler package. By following the steps outlined, you can integrate PDF-to-image conversion capabilities into your Node.js applications, enabling a wide range of possibilities for handling and manipulating PDF documents programmatically.

On the other hand, IronPDF is a powerful C# library that facilitates PDF manipulation and conversion tasks. Its ability to convert PDF to images offers a convenient way to extract images or generate image representations of PDF pages programmatically. By leveraging IronPDF's features, developers can seamlessly integrate PDF-to-image conversion functionality into their C# applications.

IronPDF is free for development and can be licensed for commercial use. Moreover, you can also use it in commercial mode with a free trial.