In this article Purpose Today's applications must support high-quality text rendering, resolution-independent outline fonts, and full Unicode text and layout support. A device-independent text layout system that improves text readability in documents and in UI. Hardware-accelerated text, when used with Direct2D. Support for multi-format text.
Direct2D was designed to work with the text operations of the new text API, DirectWrite. To make using the DirectWrite API simpler, render targets provide three methods for rendering DirectWrite text resources: DrawText, DrawTextLayout, and DrawGlyphRun. DirectWrite, a DirectX API, provides these features and more: A device-independent text layout system that improves text readability in documents and in UI. High-quality, sub-pixel, ClearType text rendering that can use GDI, Direct2D, or application-specific rendering technology. DirectWrite is a text layout and glyph rendering API by Microsoft. It was designed to replace GDI /GDI+ and Uniscribe for screen-oriented rendering and was shipped with Windows 7 and Windows Server R2, as well as Windows Vista and Windows Server (with Platform Update installed). .
Yi Multiple Layers of Functionality DirectWrite provides factored layers of functionality, with each layer interacting seamlessly with the next. The API design gives application developers the freedom and flexibility to adopt individual layers depending on their needs and schedule.
The following diagram shows the relationship between these layers. It directwrite api downloads services for the application to measure, display, and interact with richly formatted text strings. Text-intensive applications that implement their own layout engine may use the next layer down: The script processor breaks down a chunk of text into script blocks and handles the mapping between Unicode representations to the appropriate glyph representation in the font so the text of the script can be correctly displayed in the correct language.
The layout system used by the text layout API layer is built upon the font and script processing system. The glyph-rendering layer is the lowest layer of functionality and provides glyph-rendering functionality for applications that implement their own text layout engine.
The glyph rendering layer is also useful for applications that implement a custom renderer to modify the glyph-drawing behavior through the callback function in the DirectWrite text-formatting API.
The DirectWrite font system is available to all the DirectWrite functional layers and enables an application to access font and glyph information.
It is designed to handle common font technologies and data formats. The DirectWrite font model follows the common typographic practice of supporting any number of weights, styles, and stretches in the same font family. This model, the same model followed by WPF and CSS, specifies that fonts differing only in weight bold, light, and so onstyle upright, italic, or oblique or stretch narrow, condensed, wide, and so on are considered to be members of a single font family.
Improved Text Rendering with ClearType Improving readability on the screen is a key requirement for all Windows applications.
The evidence from research in cognitive psychology indicates that we need to be able to recognize every letter accurately and that even spacing between letters is critical for fast processing. Letters and words that are not symmetrical are perceived as ugly and degrade the reading experience.
The article is called "The Technology of Text" http: Text in DirectWrite is rendered using Microsoft ClearType, which enhances the clarity and readability of text.
Before these ClearType enhancements, text with a "reading" size of 10 or 12 points was difficult to display: Using the extra resolution in the subpixels provides us with fractional spacing, which improves the evenness and symmetry of the entire page.
The following two illustration show how glyphs may begin on any sub-pixel boundary when sub-pixel positioning is used. The following illustration is rendered using the GDI version of the ClearType renderer, which did not employ sub-pixel positioning.
The following illustration is rendered using the DirectWrite version of the ClearType renderer, which uses sub-pixel positioning. Note that the spacing between the letters h and n is more even in the second image and the letter o is spaced further from the letter n, more even with the letter l.
Also note how the stems on the letters l are more natural looking. The subpixel ClearType positioning offers the most accurate spacing of characters on screen, especially at small sizes where the difference between a sub-pixel and a whole pixel represents a significant proportion of glyph width.
It enables text to be measured in ideal resolution space and rendered at its natural position at the LCD color stripe, with subpixel granularity. Text measured and rendered using this technology is, by definition, resolution-independent, meaning that the exact same layout of text is achieved across the range of various display resolutions.
The Text String API adopts sub-pixel text rendering by default, which means it measures text at its ideal resolution independent of the current display resolution, and produces the glyph positioning result based on the truly scaled glyph advance widths and positioning offsets.
For large-sized text, DirectWrite also enables anti-aliasing along the y-axis to make the edges smoother and render letters as the font designer intended.
The following illustration shows y-direction anti-aliasing. Although DirectWrite text is positioned and rendered using sub-pixel ClearType by default, other rendering options are available. Many existing applications use GDI to render most of their UI, and some applications use system editing controls that continue to use GDI for text rendering.
When adding DirectWrite text to these applications, it may be necessary to sacrifice the reading experience improvements provided by sub-pixel ClearType so that text has a consistent appearance across the application.
To meet these requirements, DirectWrite also supports the following rendering options: Sub-pixel ClearType with anti-aliasing in both horizontal and vertical dimensions.
GDI compatible-width including East Asian embedded bitmap.You experience stability issues when you run an application that uses the DirectWrite API in Windows 7 or Windows Server R2.
Because Windows Presentation Foundation (WPF)4 uses DirectWrite APIs in Windows7, any WPF4-based application is . DirectWrite is a text layout and glyph rendering API by Microsoft.
It was designed to replace GDI /GDI+ and Uniscribe for screen-oriented rendering and was shipped with Windows 7 and Windows Server R2, as well as Windows Vista and Windows Server (with Platform Update installed). .
DirectWrite is a text layout and glyph rendering API by Microsoft. It was designed to replace GDI /GDI+ and Uniscribe for screen-oriented rendering and was shipped with Windows 7 and Windows Server R2, as well as Windows Vista and Windows Server (with Platform Update installed). . The download operation executes in the background until it completes or is cancelled by a CancelDownload call. CancelDownload Removes all download requests from the queue and cancels any active download operations. Download HarlinnWindowszip - MB; Updates. The code for Windows Development in C++, At the same time Microsoft introduced another new API, DirectWrite, supporting text rendering, resolution-independent outline fonts, and full Unicode text and layout support.
Download HarlinnWindowszip - MB; Updates. The code for Windows Development in C++, At the same time Microsoft introduced another new API, DirectWrite, supporting text rendering, resolution-independent outline fonts, and full Unicode text and layout support. Text Metrics In order to assist your layout, custom font selection, and other metric intensive operations, starting in Windows 8, DirectWrite has a number of new APIs to express all the info about fonts that you might require to develop rich text apps.
Introduction to DirectWrite.
Microsoft has added two interesting new API's to Windows 7: Direct2D and regardbouddhiste.com2D replaces GDI and GDI+. It can render more accurate results and has support for hardware acceleration on your graphics hardware. Applications can use DirectWrite to render richly formatted text for their UI and documents with the layout API.
For more complex scenarios, an application can work directly with glyphs, access fonts, and so on, and harness the power of DirectWrite to deliver high-quality typography.