Windows Presentation Foundation

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WPF（Windows Presentation Foundation）是美國微软公司推出.NET Framework 3.0的组成部分之一，它是一套基于XML、.NET Framework、向量绘图（vector graphic）技术的表现层（presentation layer）开发框架，微软视其为下一代用户界面（user interface）技术，将广泛被用于下一代的Windows平台（Windows Vista）的界面开发。

WPF使用一种新的XAML（Extensible Application Markup Language）语言来开发界面，这将把界面开发以及后台逻辑很好的分开，降低了耦合度，使用户界面设计师与程序开发者能更好的合作，降低维护和更新的成本。

WPF/E 是WPF的子集合，全名是：Windows Presentation Foundation Everywhere。在基於XAML與JavaScript之下，可跨越各種平台。

目录 1 特徵 1.1 繪圖服務 1.2 佈署 1.3 互操作性 1.4 媒體播放 1.5 資料鏈結 1.6 使用者介面 1.7 文件 2 工具 3 WPF/E 4 WPF 應用程式 5 外部链接

[编辑] 特徵

This article is part of the Windows Vista series.

New features

Overview

Technical and core system

Security and safety

Management and administration

Removed features

Other articles

Editions and pricing

Development history

Criticism

List of Windows Vista topics

WPF 部份之特徵如下：

[编辑] 繪圖服務

• 所有的圖形皆可由Direct3D產生。
  • 目標在於統一各種顯示圖形。
  • Windows可以透過Direct3D 來減輕在繪圖任務上的負荷，這項技術乃基於電腦繪圖卡（graphics card）的 繪圖處理單元（en:Graphics Processing Unit）。
  • 支援向量繪圖（vector graphic）。
  • 支援3D透視圖並且影響2D應用程式。

[编辑] 佈署

• WPF 不僅僅是建立傳統的獨立程式（standalone applications）。其部署方式可分成兩類 standalone 與XAML Browser Applications（XBAP）觀點。這些佈署方式在程式的撰寫上大致類似。
  • 獨立程式之安裝方式可以借由 ClickOnce 或微軟安裝器（Microsoft Installer）（MSI）完成。獨立程式可被視為完全信任（full trust）具有完全存取系統資源的優點。
  • XAML Browser Application （XBAPs）是一種寄宿於網頁瀏覽器上的程式，像是Internet Explorer。寄宿的程式可取得部份信任（partial trust）的沙箱（sandbox）環境之下，且無法取得完整的系統資源，WPF的功能亦無法完全發揮。寄宿的環境必須有意地防衛惡意的程式碼。從網頁上執行XBAP（讀音 "ex-bap"）必須是毫無破綻的（沒有安全性或安裝提示）。雖然這樣的寄宿程式在感觀上與傳統微軟的DLL（out of process）有相異處。

[编辑] 互操作性

• WPF可與Win32互相操作：經由主導（hosting）機制，可以在Win32碼之下使用 Windows Presentation Foundation, 或是在Windows Presentation Foundation環境下使用Win32程式碼。^[1]
• Windows Forms 的互操作性亦可利用 ElementHost（繼承自System.Windows.Forms.ContainerControl）以及 WindowsFormsHost（繼承自System.Windows.Forms.Integration）等類別達成，同時提供了Host Avalon Element的能力。

[编辑] 媒體播放

• WPF 針對2D圖形提供形狀基元（shape primitives），內建有刷布（brushes）、畫筆（pens）、幾何（geometries），與變形 （transforms）。
• WPF 以Direct3D提供完整的3D功能。. However, WPF 提供更完整的整合性在於使用者介面上（UI）、文件（documents）, 與媒體 （media）。這使得儘可以實現 3D UI, 3D 文件, 和 3D 媒體。
• 支援了大量的圖片格式（image formats）。
• WPF 支援大量影音格式，如： WMV, MPEG 以及某些 AVI 檔。
• WPF supports time-based animations, in contrast to the frame-based approach. This delinks the speed of the animation from how the system is performing.
• 文件的呈現支援ClearType，這提供一種次像數（sub-pixel）定位功能，強化其自然風格。WPF 同時支援 OpenType字型樣式。

[编辑] 資料鏈結

• WPF 有內建資料服務結合，可以讓應用程式發展者在應用程式內鏈結並處理資料。一共有三種資料鏈接方式：
  • one time: 客戶端（client）必須忽略伺服端（server）的更新動作。
  • one way: 客戶端僅被准許讀取資料（read-only）。
  • two way: 客戶端可讀取並讀進伺服端。
• 資料連結在展示層並無太大負擔。WPF 提供有資料樣板（data templates）來控制這些資料。

[编辑] 使用者介面

• WPF提供了內建元件控制項集合，包括有按鈕（button）、選單（menu）、列表盒（list box）。內建元件缺乏DataGrid但第三協力廠商已有支援。
• WPF 的邏輯層與外觀展示層已形成強力的分離模式。
  • 元件的外貌樣品可以被完全改寫。
  • A control can contain any other control or layout, allowing for unprecedented control over composition.

[编辑] 文件

WPF includes a number of text rendering features that were not available in GDI. This is the first Windows programming interface to expose OpenType features to software developers, supporting both OpenType, TrueType, and OpenType CFF (Compact Font Format) fonts.

對 OpenType 的支援包括：

• 縛（Ligatures）
• 舊式數碼（Old-style numerals） (for example, parts of the glyph hang below the text baseline)
• Swash variants
• 碎形（Fractions）
• Superscript and Subscript
• Small caps

Other typography features provided by WPF include line-level justification and Ruby characters.

WPF text rendering takes advantage of advances in ClearType technology, such as sub-pixel positioning, y-direction anti-aliasing, hardware-accelerated text rendering, as well as aggressive caching of pre-rendered text in video memory.^[2] The extent to which this is supported is dependent on the video card. DirectX 10 cards will be able to cache the font glyphs in video memory, then perform the composition (assembling of character glyphs in the correct order, with the correct spacing), alpha-blending (application of anti-aliasing), and RGB blending (ClearType's sub-pixel color calculations), entirely in hardware. This means that only the original glyphs need to be stored in video memory once per font (Microsoft estimates that this would require 2MB of video memory per font), and other operations such as the display of anti-aliased text on top of other graphics – including video – can also be done with no computation effort on the part of the CPU. DirectX 9 cards are only able to cache the alpha-blended glyphs in memory, thus requiring the CPU to handle glyph composition and alpha-blending before passing this to the video card. Caching these partially-rendered glyphs requires significantly more memory (Microsoft estimates 5MB per process). Cards that don't support DirectX 9 have no hardware-accelerated text rendering capabilities. ClearType font smoothing however cannot be optionally turned off.

Animated text is also supported; this refers to animated glyphs, as well as real-time changes in position, size, color, and opacity of the text.

[编辑] 工具

WPF（Windows Presentation Foundation）的開發工具數量相當可觀，目前大部份仍處於開發階級，少部份已釋出。

• Microsoft Cider 是一種內插（add-in）Visual Studio 2005 designer 的工具，用於建立Windows Presentation Foundation 應用程式。. Meant to be used by application developers.
• Microsoft Expression Blend is a designer-oriented tool that provides a canvas for the creation of WPF applications with 2D and 3D graphics, text and forms content. It generates XAML that may be exported into other tools.
• Microsoft Expression Design 可將點矩陣（bitmap）與 2D-vector graphics 匯出成 XAML.
• Electric Rain ZAM 3D provides an interactive graphical design environment for constructing 3D models that can be exported into XAML.
• Mobiform Aurora provides an alternative tool for constructing WPF user interfaces.
• Xceed DataGrid for WPF free full-featured DataGrid control for WPF.

[编辑] WPF/E

主条目：WPF/E和Windows Presentation Foundation/Everywhere

Windows Presentation Foundation/Everywhere 是一種可跨平台的 XAML-based WPF 技術^[3] that provides features such as video, vector graphics, and animations to multiple operating systems including Windows Vista, Windows XP, and Mac OS X. Specifically, WPF/E is provided as an add-on for Mozilla Firefox, Internet Explorer 6 and above, and Apple Safari. WPF/E and WPF only share XAML presentation layer.

These extensions will allow browsers to use WPF/E graphics capabilities. The browser extensions will be similar to Adobe Flash, a highly popular graphic plug-in available for most browsers. Internet Explorer will have native support for WPF in Windows Vista, and will support WPF/E in older versions.

WPF/E will work in concert with XAML and will be scriptable with JavaScript. Version 2.0 will also contain a version of the Common Language Runtime so it can execute VB.Net and C# code in a sandbox with no local file access.

Commonly mentioned as alternatives to WPF/E are Adobe Flex, Nexaweb, OpenLaszlo, and Ajax.

The first CTP of WPF/E was released in December 2006. Microsoft aims to have a final release by mid-2007.

[编辑] WPF 應用程式

WPF 是下一代圖形API 在桌面上的延伸。以WPF 撰寫應用程式，具有更高的視覺品質。下表列出微軟自家的產品或是第三協力廠商的主力產品：

主条目：List of WPF applications

• Microsoft Expression Design
• Microsoft Expression Blend
• Yahoo! Messenger
• New York Times Reader

[编辑] 外部链接

• WPF - .Net Framework 3.0 官方社区 （英文）
• The Windows Presentation Foundation community portal -- The WPF section of the .NET Framework 3.0 community site.
• MSDN Windows Presentation Foundation SDK -- Software Development Kit for WPF.
• WPFwiki.org -- The largest WPF FAQ question and answer repository & Wiki.
• Getting Started (WPF) -- Roadmap to information for developers new to WPF.
• WPF SDK Blog -- Active blog maintained by the WPF SDK team.
• Windows Presentation Foundation Unleashed -- The first WPF book to market, written by the lead developers Adam Nathan.
• Essential Windows Presentation Foundation -- An online WPF tutorial and reference, written by Chris Anderson.
• Microsoft Expression Blend -- Visual tool for creating Windows Presentation Foundation applications.
• wpf made simple -- Provides info/samples on WPF.
• XAML.net Information on XAML and XBAPs, the Windows Presentation Foundation (WPF), .NET Framework 3.0 and Windows Vista]].
• A Guided Tour of Windows Presentation Foundation -- Microsoft's overview of Windows Presentation Foundation.
• Windows Presentation Foundation Security Sandbox -- An overview of the sandbox in which WPF browser applications run.
• MSDN Forums for Windows Presentation Foundation -- Active discussion forum for WPF developers.
• WPF/E Google Group -- Discussion group and list of examples.
• Microsoft goes cross-platform with WPF/E -- WPF/E explained in an interview with Microsoft's Director of Developer Tools.
• More than meets the eye in Microsoft's plans -- News.com's article on WPF/E
• WPF page on NetFXGuide.com
• A Five Mile Overview of WPF -- A high-level overview of WPF for software developers.
• xbap.org -- Comprehensive information on XBAP applications.
• DirectX 10 Wiki - Wiki covering WPF and DirectX 10 Tutorials, Samples, Effect, News.