SVG应用中的图层处理算法

Map-layer management arithmetic of SVG application

目前点阵图像依然是Web环境下表现图形的主要方式,由于其固有的弱点,难以满足实际应用需要。而少量的几种能够在Web环境下表现矢量图形的软件也存在着通用性差、可维护性差、开放性差等问题,不利于推广应用。基于SVG(sca-lable vector graphics)规范,构建具有多图层描述能力和开放式特征的矢量图形数据结构,设计并实现能够识别多层次结构的矢量图形变换算法,是解决Web环境下复杂图形处理任务的可行途径。利用G元素的可嵌套容器性质构建了支持多图层/图块的矢量图形数据结构;依托图形对象拾取与对象属性控制机制设计了图形对象的变换算法,据此通过脚本语言和DOM(document object model)编程实现了支持多图层结构的矢量图形表现与变换功能的方法。

Presently, lattice graphics is still the primary mode of graphic object expression under the web circumstances. Because of inherent weakness, it is difficult to satisfy practical application. And a few vector graphics software under web has a series of problems, such as bad generality, maintainability and open peculiarity and so forth, which make against to its further application. Based on SVG （scalable vector graphics） criterion, vector graphics data structure is constructed with descriptive capability of much layer and open characteristic, and transformational arithmetic is designed and achieved which can identify the vector graphics with much layer. It is feasible to resolve the management of complex graphics under web environment. Using G element in possession of nested property, vector graphic data structure is framed, which support much layer and much block. And relying on graphics object catch and attribute control mechanism, graphic object transformational arithmetic is projected. So, by means of script language and DOM （document object model） program, the method is completed which support the representation and transformation function of much layer vector graphics.