The first advance in computer graphics was in the use of CRTs. There are two approaches to 2D computer graphics: vector and raster graphics. Vector graphics stores precise geometric data, topology and style such as: coordinate positions of points, the relations between points , and the color, thickness, and possible fill of the shapes. Most vector graphic systems can also use primitives of standard shapes such as circles, rectangles, etc.
Early vector-graphics displays were monochrome CRTs where the picture was drawn by the cathode ray being motivated about the screen along the required path.On a scanning display, a vector graphic image has to be transformed to a raster image to be viewed. Raster graphics is a uniform 2-dimensional grid of pixels. Each pixel has a specific value such as, for instance, brightness, color, transparency, or a combination of such values. A raster image has a finite resolution of a specific number of rows and columns. Standard computer displays shows a raster image of resolutions such as 1280 columnsx1024 rows of pixels. Today, one often combines raster and vector graphics in complex file formats.