SVG Essentials

Chapter 1. Getting Started

SVG, which stands for Scalable Vector Graphics, is an application of XML that makes it possible to represent graphic information in a compact, portable form. Interest in SVG is growing rapidly, and tools to create and view SVG files are already available from major companies. This chapter begins with a description of the two major systems of computer graphics, and describes where SVG fits into the graphics world. The chapter concludes with a brief example that uses many of the concepts that we will explore in detail in the following chapters.

Graphics Systems

The two major systems for representing graphic information on computers are raster and vector graphics.

Raster Graphics

In raster graphics, an image is represented as a rectangular array of picture elements or pixels (see Figure 1-1). Each pixel is represented either by its RGB color values or as an index into a list of colors. This series of pixels, also called a bitmap, is often stored in a compressed format. Since most modern display devices are also raster devices, displaying an image requires a viewer program to do little more than uncompress the bitmap and transfer it to the screen.

Figure 1-1. Raster graphic rectangle

Vector Graphics

In a vector graphic system, an image is described as a series of geometric shapes (see Figure 1-2). Rather than receiving a finished set of pixels, a vector viewing ...