Aspose.Words.Shaping.HarfBuzz 24.11.1

Aspose.Words.Shaping.Harfbuzz

Aspose.Words.Shaping.Harfbuzz is an add-on for Aspose.Words for .NET, a widely used document processing library. It utilizes the HarfBuzz text shaping engine to improve the rendering of OpenType fonts within documents.

Text shaping is crucial for properly displaying languages that require intricate glyph positioning and substitution, such as Arabic, Thai, Hebrew and others. By integrating HarfBuzz, Aspose.Words.Shaping.Harfbuzz allows Aspose.Words for .NET to provide more accurate text rendering and better support for OpenType fonts, ensuring that documents are displayed correctly across different platforms.

Please note: Aspose.Words.Shaping.Harfbuzz uses P/Invoke technology for invoking unmanaged functions from HarfBuzz.

Functionality

Shaping is an essential process getting text ready for display. Before rendering a Unicode sequence, the code points must be mapped to the corresponding glyphs from the font, and these glyphs need to be correctly positioned relative to each other.

As mentioned above, shaping is critical for displaying languages that require intricate glyph positioning and substitution. But for other languages based on the Latin or Cyrillic scripts, shaping is also necessary.

For correct display of fonts, shaping implements the following features:

• kerning – changing the spacing between glyphs depending on their shape

  

• ligatures (standard, contextual, historical, discretionary)

  

• number forms (lining, oldstyle)

  

• number spacing (proportional, tabular)

  

• stylistic sets – feature that allows you to apply alternative designs or styles to specific characters or groups of characters within a font

  

How to Enable Text Shaping in Aspose.Words?

Text shaping is a non-trivial task, so Aspose.Words currently offers users to choose the third-party library that best suits their needs when implementing shaping. Aspose.Words provides the ITextShaper and ITextShaperFactory interfaces and expects that a third-party library implements them.

To enable shaping in Aspose.Words, it is needed to initialize the Document.LayoutOptions.TextShaperFactory property with an instance of a class that implements the ITextShaperFactory interface.

How to Aspose.Words.Shaping.Harfbuzz Works?

Aspose.Words.Shaping.Harfbuzz implements the ITextShaper interface, using the harfbuzz.dll library underhood. In fact, Aspose.Words.Shaping.Harfbuzz is just an adapter that allows to use the harfbuzz.dll text shaping library in Aspose.Words.

The package provides class HarfBuzzTextShaperFactory which implements ITextShaperFactory and also BasicTextShaperCache which just wraps up HarfBuzzTextShaperFactory and supports caching and reusing of the loaded font files.

Aspose.Words.Shaping.Harfbuzz exposes a static property Aspose.Words.Shaping.HarfBuzz.HarfBuzzTextShaperFactory.Instance which is an instance of the shaper factory supporting caching. Actually, to use Aspose.Words.Shaping.HarfBuzz you just need to initialize the Document.LayoutOptions.TextShaperFactory property with this static field:

Document.LayoutOptions.TextShaperFactory = Aspose.Words.Shaping.HarfBuzz.HarfBuzzTextShaperFactory.Instance;

Getting Started

Would you like to give it a try? Let us guide you through the process in just a few simple steps. For Windows platforms, no additional efforts are required to install HarfBuzz, as Aspose.Words.Shaping.Harfbuzz already includes the compiled HarfBuzz library.

For other systems, Aspose.Words.Shaping.Harfbuzz relies on the already installed HarfBuzz library. For instance, on many Linux-based systems, HarfBuzz is installed system-wide by default. If not, there is usually a package available for installation through the package manager.

You can run the following code snippets in C# to see how our library works. Also feel free to check out the GitHub Repository for other common use cases.

// Load a Word file from the local drive.
Document doc = new Document("InputWordDocument.docx");

// Initialize TextShaper factory with predefined instance.
doc.LayoutOptions.TextShaperFactory = Aspose.Words.Shaping.HarfBuzz.HarfBuzzTextShaperFactory.Instance;

// Save it to HTML format.
doc.Save("OutputHtmlDocument.pdf");