Tipologia no WPF

This topic introduces the major typographic features of WPF. These features include improved quality and performance of text rendering, OpenType typography support, enhanced international text, enhanced font support, and new text application programming interfaces (APIs).

Este tópico contém as seguintes seções.

• Improved Quality and Performance of Text
• Rich Typography
• Enhanced International Text Support
• Enhanced Font Support
• New Text Application Programming Interfaces (APIs)
• Tópicos relacionados

Improved Quality and Performance of Text

Texto em WPF é processado usando Microsoft ClearType, que aprimora a clareza e legibilidade do texto. ClearTypeé uma tecnologia de software desenvolvida pela Microsoft que melhora a legibilidade do texto existentes LCDs (telas de cristal), como telas de laptop, Pocket PC telas e monitores de tela plana. ClearTypeusa o processamento de sub-pixel que permite que o texto a ser exibido com uma maior fidelidade à sua forma verdadeira por alinhamento de caracteres em uma parte fracionária de um pixel. The extra resolution increases the sharpness of the tiny details in text display, making it much easier to read over long durations. Another improvement of ClearType in WPF is y-direction anti-aliasing, which smoothes the tops and bottoms of shallow curves in text characters. For more details on ClearType features, see Visão Geral de ClearType.

Text with ClearType y-direction antialiasing

The entire text rendering pipeline can be hardware-accelerated in WPF provided your machine meets the minimum level of hardware required. Rendering that cannot be performed using hardware falls back to software rendering. Hardware-acceleration affects all phases of the text rendering pipeline—from storing individual glyphs, compositing glyphs into glyph runs, applying effects, to applying the ClearType blending algorithm to the final displayed output. For more information on hardware acceleration, see Níveis de Renderização Gráfica.

Diagram of the text rendering pipeline

In addition, animated text, whether by character or glyph, takes full advantage of the graphics hardware capability enabled by WPF. This results in smooth text animation.

Rich Typography

The OpenType font format is an extension of the TrueType® font format. The OpenType font format was developed jointly by Microsoft and Adobe, and provides a rich assortment of advanced typographic features. The Typography object exposes many of the advanced features of OpenType fonts, such as stylistic alternates and swashes. The Windows SDK provides a set of sample OpenType fonts that are designed with rich features, such as the Pericles and Pescadero fonts. For more information, see Pacote Exemplo de fontes OpenType.

The Pericles OpenType font contains additional glyphs that provide stylistic alternates to the standard set of glyphs. The following text displays stylistic alternate glyphs.

Text using OpenType stylistic alternate glyphs

Swashes are decorative glyphs that use elaborate ornamentation often associated with calligraphy. The following text displays standard and swash glyphs for the Pescadero font.

Text using OpenType standard and swash glyphs

For more details on OpenType features, see Recursos de fontes OpenType.

Enhanced International Text Support

WPF provides enhanced international text support by providing the following features:

• Automatic line-spacing in all writing systems, using adaptive measurement.

• Broad support for international text. For more information, see Globalização para WPF.

• Language-guided line breaking, hyphenation, and justification.

Enhanced Font Support

WPF provides enhanced font support by providing the following features:

• Unicode for all text. Font behavior and selection no longer require charset or codepage.

• Font behavior independent of global settings, such as system locale.

• Separate FontWeight, FontStretch, and FontStyle types for defining a FontFamily. This provides greater flexibility than in Win32 programming, in which Boolean combinations of italic and bold are used to define a font family.

• Writing direction (horizontal versus vertical) handled independent of font name.

• Font linking and font fallback in a portable XML file, using composite font technology. Composite fonts allow for the construction of full range multilingual fonts. Fontes compostas também fornecem um mecanismo que evita a exibição de glifos ausentes. For more information, see the remarks in the FontFamily class.

• International fonts built from composite fonts, using a group of single-language fonts. This saves on resource costs when developing fonts for multiple languages.

• Composite fonts embedded in a document, thereby providing document portability. For more information, see the remarks in the FontFamily class.

New Text Application Programming Interfaces (APIs)

WPF provides several text APIs for developers to use when including text in their applications. These APIs are grouped into three categories:

• Layout and user interface. The common text controls for the graphical user interface (GUI).

• Lightweight text drawing. Allows you to draw text directly to objects.

• Advanced text formatting. Allows you to implement a custom text engine.

Layout and User Interface

No nível mais alto de funcionalidade, o texto APIs fornecer comuns user interface (UI) controles, como Label, TextBlock, e TextBox. These controls provide the basic UI elements within an application, and offer an easy way to present and interact with text. Controls such as RichTextBox and PasswordBox enable more advanced or specialized text-handling. And classes such as TextRange, TextSelection, and TextPointer enable useful text manipulation. These UI controls provide properties such as FontFamily, FontSize, and FontStyle, which enable you to control the font that is used to render the text.

Using Bitmap Effects, Transforms, and Text Effects

WPF allows you to create visually interesting uses of text by uses features such as bitmap effects, transforms, and text effects. The following example shows a typical type of a drop shadow effect applied to text.

Text with a drop shadow

The following example shows a drop shadow effect and noise applied to text.

Text with a drop shadow and noise

The following example shows an outer glow effect applied to text.

Text with an outer glow effect

The following example shows a blur effect applied to text.

Text with a blur effect

The following example shows the second line of text scaled by 150% along the x-axis, and the third line of text scaled by 150% along the y-axis.

Text using a ScaleTransform

The following example shows text skewed along the x-axis.

Text using a SkewTransform

A TextEffect object is a helper object that allows you to treat text as one or more groups of characters in a text string. O exemplo a seguir mostra um caractere individual seja girado. Each character is rotated independently at 1-second intervals.

Example of a rotating text effect animation

Using Flow Documents

In addition to the common UI controls, WPF offers a layout control for text presentation—the FlowDocument element. O FlowDocument elemento, em conjunto com o DocumentViewer elemento, fornece um controle para grandes quantidades de texto com variados requisitos de layout. Layout controls provide access to advanced typography through the Typography object and font-related properties of other UI controls.

The following example shows text content hosted in a FlowDocumentReader, which provides search, navigation, pagination, and content scaling support.

Text hosted in a FlowDocumentReader

For more information, see Documentos no WPF.

Lightweight Text Drawing

You can draw text directly to WPF objects by using the DrawText method of the DrawingContext object. To use this method, you create a FormattedText object. This object allows you to draw multi-line text, in which each character in the text can be individually formatted. The functionality of the FormattedText object contains much of the functionality of the DrawText flags in the Win32 API. In addition, the FormattedText object contains functionality such as ellipsis support, in which an ellipsis is displayed when text exceeds its bounds. The following example shows text that has several formats applied to it, including a linear gradient on the second and third words.

Displayed text using FormattedText object

You can convert formatted text into Geometry objects, allowing you to create other types of visually interesting text. For example, you could create a Geometry object based on the outline of a text string.

Text outline using a linear gradient brush

The following examples illustrate several ways of creating interesting visual effects by modifying the stroke, fill, and highlight of converted text.

Example of setting stroke and fill to different colors

Example of an image brush applied to the stroke

Example of an image brush applied to the stroke and highlight

For more information on the FormattedText object, see Drawing Formatted Text.

Advanced Text Formatting

At the most advanced level of the text APIs, WPF offers you the ability to create custom text layout by using the TextFormatter object and other types in the System.Windows.Media.TextFormatting namespace. The TextFormatter and associated classes allow you to implement custom text layout that supports your own definition of character formats, paragraph styles, line breaking rules, and other layout features for international text. There are very few cases in which you would want to override the default implementation of the WPF text layout support. No entanto, se você estivesse criando um controle ou aplicativo de edição de texto, você pode exigir uma implementação diferente do padrão WPF de implementação.

Unlike a traditional text API, the TextFormatter interacts with a text layout client through a set of callback methods. It requires the client to provide these methods in an implementation of the TextSource class. The following diagram illustrates the text layout interaction between the client application and TextFormatter.

Interaction between application and TextFormatter

For more details on creating custom text layout, see Formatação de Texto Avançada.

Consulte também

Referência

FormattedText

TextFormatter

Conceitos

Visão Geral de ClearType

Recursos de fontes OpenType

Drawing Formatted Text

Formatação de Texto Avançada

Otimização de desempenho: Texto

Outros recursos

Microsoft Typography