Render EBooks as HTML, PDF, and image files Leave feedback

GroupDocs.Viewer for Node.js via Java allows you to render your EBooks (EPUB, MOBI) in HTML, PDF, PNG, and JPEG formats. You do not need to use any book reader to load and view EBooks within your Node.js application (web or desktop).

To start using the GroupDocs.Viewer API, create a Viewer class instance. Pass a book you want to view to the class constructor. You can load the book from a file or stream. Call one of the Viewer.view method overloads to convert the EBook to HTML, PDF, or image format.

View EBooks online View demos and examples on GitHub

GroupDocs.Viewer supports the following EBooks file formats:

• EPUB (.EPUB)
• MOBI (.MOBI)

Create an HtmlViewOptions class instance and pass it to the Viewer.view method to convert an EBook file to HTML. The HtmlViewOptions class properties allow you to control the conversion process. For instance, you can embed all external resources in the generated HTML file, minify the output file, and optimize it for printing. Refer to the following documentation section for details: Rendering to HTML.

To save all elements of an HTML page (including text, graphics, and stylesheets) into a single file, call the HtmlViewOptions.forEmbeddedResources method and specify the output file name.

const viewer = new groupdocs.viewer.Viewer("abook.epub")
// Create an HTML file for the drawing.
// {0} is replaced with the current page number in the file name.
const viewOptions = groupdocs.viewer.HtmlViewOptions.forEmbeddedResources("page_{0}.html")
viewer.view(viewOptions)

The following image demonstrates the result:

If you want to store an HTML file and additional resource files (such as fonts, images, and stylesheets) separately, call the HtmlViewOptions.forExternalResources method and pass the following parameters:

• The output file path format
• The path format for the folder with external resources
• The resource URL format

const viewer = new groupdocs.viewer.Viewer("abook.epub")
// Create an HTML file for each page.
// Specify the HTML file names and location of external resources.
// {0} and {1} are replaced with the current page number and resource name, respectively.
const viewOptions = groupdocs.viewer.HtmlViewOptions.forExternalResources("page_{0}.html", "page_{0}/resource_{0}_{1}", "page_{0}/resource_{0}_{1}")
viewer.view(viewOptions)

The image below demonstrates the result. External resources are placed in a separate folder.

Create a PdfViewOptions class instance and pass it to the Viewer.view method to convert an EBook file to PDF. The PdfViewOptions class properties allow you to control the conversion process. For instance, you can protect the output PDF file, reorder its pages, and specify the quality of document images. Refer to the following documentation section for details: Rendering to PDF.

const viewer = new groupdocs.viewer.Viewer("abook.epub")
// Create a PDF file for the document.
// Specify the PDF file name.
const viewOptions = groupdocs.viewer.PdfViewOptions("output.pdf")
viewer.view(viewOptions)

The following image demonstrates the result:

Create a PngViewOptions class instance and pass it to the Viewer.view method to convert an EBook file to PNG. Use the PngViewOptions.setHeight and PngViewOptions.setWidth methods to specify the output image size in pixels.

const viewer = new groupdocs.viewer.Viewer("abook.epub")
// Create a PNG image for each document page.
// {0} is replaced with the current page number in the image name.
const viewOptions = groupdocs.viewer.PngViewOptions("output_{0}.png")
// Set width and height.
viewOptions.setWidth(950)
viewOptions.setHeight(550)
viewer.view(viewOptions)

Create a JpgViewOptions class instance and pass it to the Viewer.view method to convert an EBook file to JPEG. Use the JpgViewOptions.setHeight and JpgViewOptions.setWidth methods to specify the output image size in pixels.

const viewer = new groupdocs.viewer.Viewer("abook.epub")
// Create a JPG image for each document page.
// {0} is replaced with the current page number in the image name.
const viewOptions = groupdocs.viewer.PngViewOptions("output_{0}.jpg")
// Set width and height.
viewOptions.setWidth(950)
viewOptions.setHeight(550)
viewer.view(viewOptions)