How to render and display PDF layers using advanced rendering settings

Introduction

Sometimes you need to display only a part of the actual content contained on the PDF doc’s page, or maybe just working on a custom PDF viewer with support for layers for different types of content. E.g. you may want to separate images, text, annotations, graphics paths etc. and allow users to switch between them. 

In this article we’ll show how to use rendering settings of Apitron PDF Rasterizer engine and get the desired layered rendering done. An advanced and complete code sample can be downloaded from our github repo, it’s called WpfPdfViewer.

 

The code

It’s very easy to turn desired layers of content on and off while rendering the PDF page, the only thing you need is to use the corresponding setting of the RenderingSettings class. See below:

RenderingSettings renderingSettings = new RenderingSettings();

renderingSettings.DrawText = true;

renderingSettings.DrawImages = true;

renderingSettings.DrawPaths = true;

renderingSettings.DrawAnotations = true;

renderingSettings.AnnotationRenderingSettings = new RenderingSettings();

renderingSettings.AnnotationRenderingSettings.DrawText = true;

//render the page using the settings created above

page.Render(72,72, renderingSettings);

As you can see, there’s nothing difficult here, you just set the corresponding boolean value and pass the settings object to the rendering function. It’s also possible to use separate rendering settings for annotations’ content, e.g. you can turn off the text rendering for annotations while leaving other textual context shown. A few images below demonstrate the effects of these settings.

Pic. 1 A completely rendered page

Pic. 2 Images turned off

 

Pic. 3 Text turned off

Pic. 4 Graphics paths turned on

Pic. 5 Graphics paths turned off

 

Summary

As you could see from the examples shown, the Apitron PDF Rasterizer for .NET is a very versatile tool allowing you to handle all rendering task related to PDF rendering and also navigation (see the bookmarks tab on the left, it was created using rasterizer’s API). Contact us if you have any questions, we’re always ready to help you.