Generate PDFs from a template on Android

Nutrient Android SDK enables you to create a new PDF document from a template. Our SDK ships with a predefined list of page patterns.

In addition to these built-in patterns, you can use the PagePattern constructors, which can take either a DataProvider or a file Uri to build customized page templates from your own PDF documents.

ℹ️ Note: This feature requires the Document Editor component to be enabled in your license.

The PageTemplate class

PageTemplate has two constructors you can use depending on what you’re trying to achieve:

• PageTemplate(PdfDocument sourceDocument, int pageIndex, String templateName, Drawable previewImage) will instantiate a template that takes the source document’s page at the provided index.

• PageTemplate(PagePattern pagePattern, String templateName, Drawable previewImage) will instantiate a template that’s intended to be used as a tiled pattern. If you want to add a page with a repeating pattern to a document, this is the initializer you’ll use.

ℹ️ Note: Creating a tiled pattern page template requires the source document to be exported correctly. This means that the source PDF needs to contain a pattern itself. If a PageTemplate is instantiated using the tiled pattern initializer and the source document doesn’t contain a pattern, the rendering will fail silently.

Check out CustomPageTemplatesExample.java in the Catalog app to see PageTemplate in action.

Custom tiled templates

Many use cases for page templates require the background being tiled (or patterned).

A page is considered tiled if there are one or more images repeated on the page.

For a PDF to be able to work as a source for a tiled page template using PageTemplate(PagePattern pagePattern, String templateName, Drawable previewImage), it has to have actual pattern path information embedded.

To accomplish this, you can use Adobe Illustrator or any other vector editing tool.

When creating your own patterns, consider the following points:

1. What’s rendered on the page is the path information embedded in the PDF and not the actual PDF.

2. If your custom pattern needs certain spacing between tiles, that information needs to be included within the pattern information as well. Currently, there’s no way to specify spacing between tiles from the Nutrient API.

Click here to download a custom sample template.

Using PageTemplate

Create a NewPage object using the emptyPage method of its builder. The NewPage.Builder type allows you to customize various properties of the page, such as the background color or page size:

// Create a configuration for an empty A4 size page with a white background color.
val newPage = NewPage
    .emptyPage(NewPage.PAGE_SIZE_A4)
    .backgroundColor(Color.WHITE)
    .build()

// Create a configuration for an empty A4 size page with a white background color.
final NewPage newPage = NewPage
    .emptyPage(NewPage.PAGE_SIZE_A4)
    .backgroundColor(Color.WHITE)
    .build();

Using PdfProcessor

The PdfProcessor class allows you to use PdfProcessorTasks to perform many types of operations on PDF documents. These operations include document creation, merging, and modification.

After configuring a page as described in the first section, you can create a PdfProcessor and add the NewPage to it. Feeding that task into the PdfProcessor will then generate the actual PDF.

The example below shows how to generate a PDF using the PdfProcessor API:

val outputFile: File = ...
val pdfProcessorTask = PdfProcessorTask.newPage(newPage)
val disposable = PdfProcessor.processDocumentAsync(pdfProcessorTask, outputFile)
    .subscribe { progress ->  }

final File outputFile = ...
final PdfProcessorTask pdfProcessorTask = PdfProcessorTask.newPage(newPage);
final Disposable disposable = PdfProcessor.processDocumentAsync(pdfProcessorTask, outputFile)
    .subscribe(progress -> { });