摘 要
伴隨著信息家電，手持設(shè)備，無線設(shè)備等的迅速發(fā)展，相應(yīng)的硬件和軟件也得到迅速發(fā)展。許多設(shè)備都配有 Intel，MIPS，摩托羅拉等公司生產(chǎn)的32位微處理器，甚至還使用了液晶顯示器。許多開發(fā)商也開始為這些設(shè)備提供界面友好的嵌入式操作系統(tǒng)。
利用Linux搭建嵌入式操作系統(tǒng)是近年來出現(xiàn)的最令人振奮的方案。這有多方面的原因。首先，運行在嵌入式系統(tǒng)上的Linux能夠提供全功能的桌面計算（Desktop Computing），且由于其開放代碼，定制變得非常方便。其次，Linux 已經(jīng)支持大多數(shù)嵌入式系統(tǒng)上使用的芯片，包括 StrongARM , MIPS 和 PowerPC。 最后，Linux是免費的，使用Linux 不需要付出任何費用。所以利用 Linux 作為底層操作系統(tǒng), 其上使用一個 GUI 系統(tǒng)成為現(xiàn)在日益流行的嵌入式操作系統(tǒng)的解決方案。
市場上常見的 PDA 等小型手持式設(shè)備上，以前由于硬件條件等的限制，我們看到的用戶界面都非常簡單，幾乎看不到 PC 機上華麗美觀的 GUI 界面。但最近出現(xiàn)的 Palm 等手持式電腦或者在 Windows CE 等面向嵌入式系統(tǒng)的操作系統(tǒng)上，我們已經(jīng)看到了完整的圖形用戶界面支持。隨著手持式設(shè)備的硬件條件的提高，估計嵌入式系統(tǒng)對輕量級 GUI 的需求會越來越迫切。近來的市場需求也顯示，越來越多的嵌入式系統(tǒng)，包括 PDA、機頂盒、DVD/VCD 播放機、WAP 手機等等系統(tǒng)均要求提供全功能的 Web 瀏覽器。這包括 HTML 4.0 的支持、JavaScript 的支持，甚至包括 Java 虛擬機的支持。而這一切均要求有一個高性能、高可靠的 GUI 系統(tǒng)的支持。
受導(dǎo)師的影響，本人長期以來對以Linux 操作系統(tǒng)比較感興趣，并從研二開始加入由魏永明先生發(fā)起的 MiniGUI 項目，對整個MiniGUI系統(tǒng)及同類系統(tǒng)如 Microwindows 等進行了一定的研究，并對 MiniGUI 進行了一定的改進和功能擴充。本論文基于這些事實，對面向嵌入式系統(tǒng)的 GUI 系統(tǒng)的體系結(jié)構(gòu)和一些技術(shù)內(nèi)幕做了較深入的探討。
論文首先概述了嵌入式系統(tǒng)及用戶界面的發(fā)展情況，接著介紹了幾種嵌入式系統(tǒng)下的圖形用戶界面，通過相互比較，指出和通用的圖形用戶界面系統(tǒng)相比，嵌入式系統(tǒng)下的圖形用戶界面需要有輕型、占用資源少，高性能，高可靠性，可配置等特點。第三章介紹了典型系統(tǒng)MiniGUI，第四章介紹了本人實現(xiàn)的MiniGUI對Type1 字體的支持。本文的第五章將介紹 MiniGUI 輸入和圖形輸入/輸出引擎的設(shè)計，實現(xiàn)難點及相關(guān)的一些技術(shù)細節(jié)。MiniGUI的私有輸入和圖形輸入/輸出引擎為本人設(shè)計實現(xiàn)，在這些過程中獲得的一些寶貴經(jīng)驗將一并介紹。第六章給出MiniGUI的一些應(yīng)用實例。最后是一點感想和展望。

關(guān)鍵詞： 圖形用戶界面； 嵌入式系統(tǒng)；私有輸入和圖形輸入/輸出引擎。

Abstract
In the fast-changing world of embedded, handheld and wireless devices, there are many hardware and software design changes taking place. Many devices now feature 32-bit microprocessors from Intel, MIPS and Motorola, as well as larger LCD graphical displays. In order to leverage the significant results gained in the last ten years, many developers are turning to using friendly user interface operating systems with these new embedded designs.
One of the most promising emerging areas seems to be running Linux in these environments, for a couple of good reasons: Linux on embedded systems brings with it the entire power of desktop computing, along with many solutions already running. Linux, being open source, allows any aspect of the solution to be fully understood and then customized for a particular application. Linux also supports all the new microprocessors typically included in embedded designs, including StrongARM, MIPS and PowerPC. Finally, Linux is free, with no royalty payments required for it’s use.So using linux as operating system , with a GUI system built on, seems to be a good solution.
For the handled devices on the market such as PDA, as to the poor hardware in old days, the user interface was very simple, we could hardly see the colorful GUI which was supported by PC. But recently we found that some embedded operating systems such as Windows CE and Palm OS, have supported complete GUI features. With the great performance improvement of the hardware, we think that the need for mini GUI systems is urgent.
Under the influence of my tutor , Professor Li, I got interest with Linux operating system several years ago. And from Grade 2, I took part in project MiniGUI, initiated by Wei Yongming, a former teacher of Tsinghua University. I soon got familiar with it, and also its opponent Microwindows. Then I did some optimization for MiniGUI and also wrote a native low-level engine for it. Based on these facts, this thesis demonstrate architecture and internals of GUI system used on embedded systems.
At first, the thesis outlines the history of embedded systems and user interface, then we compare several GUI systems under embedded systems, point out the peculiarity of GUI on embedded systems, that is, lightness, less resource requirement, quicker response, high reliability and easy configuration. In chapter 3, we introduce typical system MiniGUI. In chapter 4, we introduce supporting for Type 1 font on MiniGUI. The native engine of MiniGUI is developed by the author, in chapter 5, the design and implementation of native engine is introduced. Also some experience gained in the coding process is included. Chapter 6 give some examples, and the last chapter gives some conclusion and foresight.

Keywords: GUI; Embedded System; Native Input & Graphics I..