共查询到20条相似文献,搜索用时 140 毫秒
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在当前颇具竟争性的商业环境中,程序的界面已不仅仅是装饰物,而成为一个软件成功的重要的因素之一。 编写界面的基本原则是实用,也就是说不必说明,从界面上直观地就告诉了用户,这个程序是干什么用的,怎么用。方便用户是程序设计的目标。图形界面或图形和文本的结合应用能较好地解决这一问题。本文介绍了使用PASCAL语言实现图形界面设计和控制的一种方法。 实现图形界面设计需要做两件事:一件事是画出图形界面;另一件事是对这视口进行控制。解决第一件事就是利用色彩的明暗对比,来产生 相似文献
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针对当前各种嵌入式系统开发中存在的图形界面开发较难的现状,介绍了一种新型的具有简便的图形界面开发功能的嵌入式系统--QNX;通过其自带的PhAB开发工具,可以方便地开发出用户所需的良好界面;根据QNX强实时性和高可靠性的特点,结合无人机地面控制台嵌入式系统的开发,论述了QNX下嵌入式系统的开发过程以及图形界面的开发方法.叙述了控制台软件的设计思想,给出了软件图形界面,对用户定制其它的带有图形界面的嵌入式系统具有一定的指导意义;通过实时性测试分析可以看出,系统实时响应时间在1~28ms之间,完全满足实时系统的要求. 相似文献
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嵌入式Linux下Qt/Embedded的应用 总被引:5,自引:3,他引:5
随着嵌入式系统的发展,用于实现与用户交流功能的嵌入式GUI成为研究中的一个重点。嵌入式Linux下,如粜图形界面接口采用的是Qt/Embedded,则必须采用Linux的帧缓冲设备来处理相关的底层命令。帧缓冲是Linux为图形设备提供的一个抽象接口.是Qt/Embcdded的底层图形引擎。文中介绍了Linux帧缓冲设备驱动程序框架,基于三星公司的S3C2410x处理器的开发平台,系统给出了嵌入式圆形界面GUI的移植,包括编译环境的建立,编译参数的设置等。 相似文献
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新一代的税控收款机对图形界面的交互能力有很高的要求.开发满足市场特点的图形开发系统也势在必行,本文在嵌入式系统μClinux的环境下,采用LCD Framebuffer和MiniGUI设计并实现了新一代税控机图形界面的开发.此系统也对其它嵌入式图形系统的开发提供了很好的借鉴作用。 相似文献
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嵌入式Linux下Qt/Embedded的应用 总被引:1,自引:0,他引:1
随着嵌入式系统的发展,用于实现与用户交流功能的嵌入式GUI成为研究中的一个重点。嵌入式Linux下,如果图形界面接口采用的是Qt/Embedded,则必须采用Linux的帧缓冲设备来处理相关的底层命令。帧缓冲是Linux为图形设备提供的一个抽象接口,是Qt/Embedded的底层图形引擎。文中介绍了Linux帧缓冲设备驱动程序框架,基于三星公司的S3C2410x处理器的开发平台,系统给出了嵌入式图形界面GUI的移植,包括编译环境的建立,编译参数的设置等。 相似文献
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Hierarchical graphs and clustered graphs are useful non-classical graph models for structured relational information. Hierarchical graphs are graphs with layering structures; clustered graphs are graphs with recursive clustering structures. Both have applications in CASE tools, software visualization and VLSI design. Drawing algorithms for hierarchical graphs have been well investigated. However, the problem of planar straight-line representation has not been solved completely. In this paper we answer the question: does every planar hierarchical graph admit a planar straight-line hierarchical drawing? We present an algorithm that constructs such drawings in linear time. Also, we answer a basic question for clustered graphs, that is, does every planar clustered graph admit a planar straight-line drawing with clusters drawn as convex polygons? We provide a method for such drawings based on our algorithm for hierarchical graphs. 相似文献
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We present a graph-basedmodel of a generic type system for an OO language. The type system supports the features of recursive types, generics and interfaces, which are commonly found in modern OO languages such as Java. In the classical graph theory, we define type graphs, instantiation graphs and conjunction graphs that naturally illustrate the relations among types, generics and interfaces within complex OO programs. The model employs a combination of nominal and anonymous nodes to represent respectively types that are identified by names and structures, and defines graph-based relations and operations on types including equivalence, subtyping, conjunction and instantiation. Algorithms based on the graph structures are designed for the implementation of the type system. We believe that this type system is important for the development of a graph-based logical foundation of a formal method for verification of and reasoning about OO programs. 相似文献
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The problem of counting the number of spanning trees is an old topic in graph theory with important applications to reliable network design. Usually, it is desirable to put forward a formula of the number of spanning trees for various graphs, which is not only interesting in its own right but also in practice. Since some large graphs can be composed of some existing smaller graphs by using the product of graphs, the number of spanning trees of such large graph is also closely related to that of the corresponding smaller ones. In this article, we establish a formula for the number of spanning trees in the lexicographic product of two graphs, in which one graph is an arbitrary graph G and the other is a complete multipartite graph. The results extend some of the previous work, which is closely related to the number of vertices and Lapalacian eigenvalues of smaller graphs only. 相似文献
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Automatic graph layout is an important and long-studied problem. The basic straight-edge graph layout problem is to find spatial positions for the nodes of an input graph that maximize some measure of desirability. When graph layout is intended for human consumption, we call this measure of desirability an aesthetic. We seek an algorithm that produces graph layouts of high aesthetic quality not only for general graphs, but also for specific classes of graphs, such as trees and directed acyclic graphs. The Aesthetic Graph Layout (AGLO) approach described in this paper models graph layout as a multiobjective optimization problem, where the value of a layout is determined by multiple user-controlled layout aesthetics. The current AGLO algorithm combines the power and flexibility of the simulated annealing approach of Davidson and Harel (1989) with the relative speed of the method of Fruchterman and Reingold (1991). In addition, it is more general, and incorporates several new layout aesthetics to support new layout styles. Using these aesthetics, we are able to produce pleasing displays for graphs on which these other methods flounder. 相似文献
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The problem of counting the number of spanning trees is an old topic in graph theory with important applications to reliable network design. Usually, it is desirable to put forward a formula of the number of spanning trees for various graphs, which is not only interesting in its own right but also in practice. Since some large graphs can be composed of some existing smaller graphs by using the product of graphs, the number of spanning trees of such large graph is also closely related to that of the corresponding smaller ones. In this article, we establish a formula for the number of spanning trees in the lexicographic product of two graphs, in which one graph is an arbitrary graph G and the other is a complete multipartite graph. The results extend some of the previous work, which is closely related to the number of vertices and Lapalacian eigenvalues of smaller graphs only. 相似文献
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《Computers & Education》1986,10(1):149-153
One problem with research on how students learn (using new technology) is that it is usually concerned with a specific topic, i.e. it has rather a narrow domain and it is not clear to what extent the findings are applicable to other domains. This paper discusses research in two rather different domains: novices learning programming and school pupils interpreting cartesian graphs. We discuss the findings in each domain but our main focus is to examine the extent to which general principles and issues apply across both domains. Finally, we discuss some of the implications from our research, for instructional design.In the case of novices learning programming we are concerned with the development of instructional materials for teaching computer concepts. In the case of graph interpretation the research shows that interpreting trends in graphs is a complex skill which is often performed badly by pupils—but which teachers often assume they can do. Here we are concerned with how computers can be used to help pupils to develop graph interpretation skills and basic concepts.In order to gain a detailed understanding of the learning processes involved in both domains we are using Artificial Intelligence techniques to model the cognitive processes. We shall, therefore, also discuss how such techniques can help us improve instructional design. 相似文献
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M. Ferrer Author Vitae E. Valveny Author Vitae Author Vitae H. Bunke Author Vitae 《Pattern recognition》2010,43(4):1642-1655
The median graph has been presented as a useful tool to represent a set of graphs. Nevertheless its computation is very complex and the existing algorithms are restricted to use limited amount of data. In this paper we propose a new approach for the computation of the median graph based on graph embedding. Graphs are embedded into a vector space and the median is computed in the vector domain. We have designed a procedure based on the weighted mean of a pair of graphs to go from the vector domain back to the graph domain in order to obtain a final approximation of the median graph. Experiments on three different databases containing large graphs show that we succeed to compute good approximations of the median graph. We have also applied the median graph to perform some basic classification tasks achieving reasonable good results. These experiments on real data open the door to the application of the median graph to a number of more complex machine learning algorithms where a representative of a set of graphs is needed. 相似文献
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Many problems can be cast as statistical inference on an attributed random graph. Our motivation is change detection in communication graphs. We prove that tests based on a fusion of graph-derived and content-derived metadata can be more powerful than those based on graph or content features alone. For some basic attributed random graph models, we derive fusion tests from the likelihood ratio. We describe the regions in parameter space where the fusion improves power, using both numeric results from selected small examples and analytic results on asymptotically large graphs. 相似文献
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设计一个实用的程序控制流分析工具需要解决非结构程序中goto等语句的控制流图构造问题。C语言程序控制流图生成器CfgGen的设计采用基于基本块标识的控制流图构造方法解决该问题。CfgGen程序基于规则,通过语法制导翻译标识基本块、构造控制流图,易移植和维护。CfgGen构造的控制流图标识了基本块,可以很方便地用于程序分析和优化。 相似文献