Vector Graphics

'Vector Graphics'

Vector graphics store the information about the picture to be displayed in the form of geometric objects described by coordinates. The description ‘vector’ arises from the fact that each coordinate can be thought of as a vector from the origin to the coordinate point. The geometric objects included are highly dependant upon the file format used, but can conceivably be any object which can be well defined by a small set of coordinate points. Examples of objects stored can include lines, ellipses, spline curves, text glyphs, etc.

There are also many difference forms of vector graphic file formats available. Examples include MS Windows metafiles, Autodesk DXF files and Macromedia Shockwave objects. There is no widely accepted vector graphic format available, and most are proprietary formats that are not available for incorporation into other products. The DXF format is debatably the most commonly used.

Advantages and Disadvantages

Vector graphics has several advantages over pixel graphics. Firstly, vector graphics can easily represent simple geometric objects, in file sizes that are far smaller and faster to operate on than pixel graphics. Secondly, the objects used in a vector graphic can be resized and repositioned after their creation. This is very difficult in pixel graphics. Thirdly, the entire vector graphic can be resized to any dimensions without any loss of information. The lack of resolution dependence in vector graphics is a large advantage over pixel graphics.

The disadvantages of this kind of picture are largely connected to creation and editing. It is very difficult to create a vector graphic using a scanner or digital camera, without having to ‘trace over’ a bitmap to create the picture. Consequently, most vector graphic pictures must be created by hand. Secondly, the software that renders vector graphics is usually incapable of generating effects such as the blending and blurring that are easily attainable in pixel graphics. This software is also sometimes quite expensive, and eventually the vector graphics are often converted to pixel graphics to allow them to be easily displayed on different computers.

Composite Pixel / Vector Graphics

The best of both worlds, graphics of this type incorporate both pixel and vector graphics to produce the final bitmap to be displayed on the screen. An example of this type of composite graphic is this web page. The page contains text, which is a vector graphic format (at least, if you’re viewing it using a True Type font), and has embedded pictures, some of which are vector graphics, and some of which are pixel graphics. This allows information such as text, which is described succinctly as vector graphics, to be stored efficiently alongside pixel graphics. This is not really a distinct graphical form, but is a practical convergence of two ideologies.

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