Skip to content

Reworded load-pdf-files.md #959

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
tony-xlh merged 2 commits into from
Dec 11, 2025
Merged

Reworded load-pdf-files.md #959

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
771f582
Update load-pdf-files.md to clarify PDF/A loading requirements and ra…
lyzhang0113 Dec 11, 2025
e7ac4ed
Update _articles/faq/load-pdf-files.md
lyzhang0113 Dec 11, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
40 changes: 19 additions & 21 deletions _articles/faq/load-pdf-files.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,39 +7,43 @@ keywords: Dynamic Web TWAIN, Addon, load pdf/a
breadcrumbText: How can I load PDF/A files into the Dynamic Web TWAIN SDK?
description: How can I load PDF/A files into the Dynamic Web TWAIN SDK?
date: 2021-12-01 01:09:41 +0800
last_modified: 2025-12-10 15:53:54 +0800
last_modified: 2025-12-11 14:20:54 +0800
---

# Addon

## How can I load PDF/A files into the Dynamic Web TWAIN SDK?

Dynamic Web TWAIN can load PDF/A files, but whether the PDF Rasterizer add-on is required depends on the content of the PDF/A file:
Dynamic Web TWAIN can load PDF/A files. Whether you need the **[PDF Rasterizer Add-on (PDFR)](https://www.dynamsoft.com/web-twain/pdf-to-image-javascript/)** depends entirely on the contents of the PDF/A document:

- If the PDF/A contains text or vector graphics, it must be rasterized, and therefore requires the PDF Rasterizer add-on.
- If the PDF/A contains only raster images, it can be loaded without the PDF Rasterizer.
- If the PDF/A contains **text or vector graphics**, rasterization is required → **PDFR license needed**.
- If the PDF/A contains **only raster images**, the file can be loaded **without** the PDFR add-on.

You can programmatically check whether a file needs rasterization using [`IsRasterizationRequired()`](/_articles/info/api/Addon_PDF.html#israsterizationrequired):
> [!NOTE]
> **Looking for information about generating PDF/A files?**
>
> Starting from Dynamic Web TWAIN 19.3, PDF/A creation is supported.
>
> See: [How can I generate PDF/A files?](/_articles/faq/generate-pdf-files.md)

### How to check whether rasterization is required

You can programmatically detect whether a given PDF/A file requires rasterization before loading it:

```javascript
DWTObject.Addon.PDF.IsRasterizationRequired(path); // returns true or false
```

When enabled, the add-on automatically rasterizes PDF/A documents into images when they are loaded into the viewer.

> [!NOTE]
> **Looking for information about generating PDF/A files?**
> Starting from Dynamic Web TWAIN 19.3, PDF/A creation is supported.
> See: [How can I generate PDF/A files?](/_articles/faq/generate-pdf-files.md)
If this method returns **`true`**, the SDK will need the PDFR to process the file.

### When rasterization actually happens

### When is PDF Rasterizer used?
Dynamic Web TWAIN performs rasterization **only when necessary**. If [`IsRasterizationRequired()`](/_articles/info/api/Addon_PDF.md#israsterizationrequired) returns **`true`** and the PDF Rasterizer license is configured, the SDK automatically rasterizes the PDF into images using the reader settings you specify.

Once the PDF Rasterizer (`PDFR`) is configured, it automatically rasterizes the file *only when needed*.
If rasterization is required, the PDF is converted into one or more images at the specified resolution (default **200 DPI**).
The rasterization behavior—including resolution (default **200 DPI**) and other rendering parameters—can be customized through [`SetReaderOptions()`](/_articles/info/api/Addon_PDF.md#setreaderoptions).

Rasterization may occur when using any of the following APIs (including drag-and-drop):

Rasterization may occur when using any of these APIs (including drag-and-drop):
- [ `LoadImage()` ](/_articles/info/api/WebTwain_IO.md#loadimage)
- [ `LoadImageEx()` ](/_articles/info/api/WebTwain_IO.md#loadimageex)
- [ `LoadImageFromBase64Binary()` ](/_articles/info/api/WebTwain_IO.md#loadimagefrombase64binary)
Expand All @@ -50,9 +54,3 @@ Rasterization may occur when using any of the following APIs (including drag-and
- [ `HTTPDownloadEx()` ](/_articles/info/api/WebTwain_IO.md#httpdownloadex)
- [ `HTTPDownloadThroughPost()` ](/_articles/info/api/WebTwain_IO.md#httpdownloadthroughpost)
- [ `HTTPDownloadDirectly()` ](/_articles/info/api/WebTwain_IO.md#httpdownloaddirectly)

### Important Change in v19.3
Previous versions of Dynamic Web TWAIN did **not** support exporting PDF/A files.
As of **19.3**, you can now:
- Load PDF/A files (with or without the PDF Rasterizer, depending on content), and
- Generate PDF/A files.