Dev Center
Table of contents

Thanks for Downloading Dynamic Web TWAIN 30-Day Trial!

Your download will start shortly. If your download does not begin, click here to retry.

PDF Handling

PDFs are widely used in many and various industries, and presently are the only non-image file type that Dynamic Web TWAIN supports. In this next section, we will address all the input and output operations that allow the user to properly handle PDF files.


Including the PDF addon

To include the PDF addon, simply add a reference to the corresponding JavaScript file, included in the resources folder.

<script src="Resources/addon/dynamsoft.webtwain.addon.pdf.js"></script>

If you are using the dwt package, the pdf addon is already included in the main JavaScript file ( dynamsoft.webtwain.min.js or dynamsoft.webtwain.min.mjs ) which means you can skip this step.


Open an image-only PDF file

When loading in a PDF file, Dynamic Web TWAIN tries to extract images from that file, which is why the SDK can handle image-based PDF documents by default.

Open a searchable PDF file

However, most existing PDF files contain much more than just images. For image-and-text PDF files, we need to make use of the PDF Rasterizer (PDFR for short), the main component of the PDF addon.

How PDFR works: As the name suggests, PDFR rasterizes a PDF file page by page much like a scanner. You set a resolution, and you get the resulting images in that resolution after the rasterization.

The following code shows the basic usage

var onSuccess = function() {
    console.log("Loaded a file successfully!");
var onFailure = function(errorCode, errorString) {
DWObject.IfShowFileDialog = true;
// PDF Addon is used here to ensure text-based PDF support
    convertMode: Dynamsoft.DWT.EnumDWT_ConvertMode.CM_RENDERALL,
        renderAnnotations: true;
DWObject.LoadImageEx("", Dynamsoft.DWT.EnumDWT_ImageType.IT_ALL, onSuccess, onFailure);

The method SetReaderOptions() configures how a PDF will be rasterized when being loaded into Dynamic Web TWAIN.

Other methods

Output as PDF

Save images as image-based PDFs

Dynamic Web TWAIN can output one or multiple images in the buffer as image-based PDF file(s). This feature is built into the core module, and no addon is required as was covered in the output section.

PDF save settings

However, some advanced features are only possible with the help of the PDF addon. At present, that means configuring the resulting file(s) with the API Write.Setup() as shown below

    author: "Dynamsoft-Support-Team",
    compression: Dynamsoft.DWT.EnumDWT_PDFCompressionType.PDF_JP2000,
    creator: "DWT",
    creationDate: "D:20200930",
    keyWords: "TWAIN, DWT, Dynamsoft",
    modifiedDate: "D:20200930",
    producer: "Dynamsoft Corporation",
    subject: "Demoing File",
    title: "Sample PDF Made by DWT",
    version: 1.5,
    quality: 80
DWObject.IfShowFileDialog = true;
DWObject.SaveAllAsPDF(' ', function() {}, function() {})

Note: Only the core module license is required to use this method.

Is this page helpful?

YesYes NoNo

In this article:

latest version

    • Latest Version (18.4)
    • Version 18.3
    • Version 18.1
    • Version 18.0
    • Version 17.3
    • Version 17.2.1
    • Version 17.1.1
    • Version 17.0
    • Version 16.2
    • Version 16.1.1
    Change +