SCAN CONVERSION

In computer graphics, an image is displayed by illuminating (drawing) the pixels at appropriate locations on the picture information in the refresh buffer of the display device which is read by video controller circuitry of the computer and accordingly. Voltages applied to the control grid and deflection plates are varied to get ‘on’ the desired pixel. The process of plotting the object on the screen is called scan conversion.

The Random and Raster display devices a sense can taken as compared of various basic geometric structure called primitives, straight line, circle ellipse.

The process f representing continues graphics object as a collection of discrete pixels is called scan conversion.

The random or raster display devices a scene can be taken as compared various basic geometric structure called output primitives. They are point, line, circle, ellipse and other surface.

SCAN CONVERTING A POINT

A screen is compared of a 2-D array of pixel positions with the origin at upper left corner of the screen. Every co-ordinate position is referred to as a (x, y) coordinate pair with X-value corresponding to the column positions, where as the Y-value corresponding to the Y- values. Corresponding to the row position and there initial zero values at the origin.

POINT:- A point is called scan converting point is the fundamental elements of picture representation. It is nothing, but the position in a plane, x, y, or x, y, z would represent a point either two or three dimensional space. Two points represent a line or edge and a collection of three or more points a polygon.

2. LINE SEGMENTS: – When we say the line, it extends forever both forward and backward. In graphics, we need to display only piece of lines. When we consider the piece of line, i.e. only those points which lay between two end points then this is called a line segment.

3.VECTOR:- A vector has a single direction and a length. A vector may be indicated by [Dx, Dy] where Dx denotes the distance on x-axis direction and Dy denotes the distance on Y-axis direction. When we consider a line segment, it has a fixed position in space but vector does not have a fixed position in space. The vector does not tell us the starting to move and in which direction.