Polygons Representation: Trapezoid method and Line and Point Method

Polygons representation by Trapezoid method:

In many graphics systems a polygon is represented by the trapezoid method. In this method a polygon is broken to many trapezoids by the use of two line segments. Each pixel in the trapezoid is then taken in to account.

Polygons Representation Trapezoid Method

Line and Point Method: In this method points are plotted and lines are drawn to represent the polygon in question. The following algorithm is used to enter data in the display file:

1. Read MX and MY of length N.
[MX and MY are arrays containing vertices and N is number of sides of polygon]
2. i=0
D_OP [i] <– N
D_x [i] <–MX [i]
D_y [i] <–MY [i]
3. do
D_OP[i] <–2
D_x [i] <– MX [i]
D_y[i] <– MY [i]
While (i<N)
4. D_OP [i] <– 2
D_x [i] <–MX [0]
D_y [i] <–MY [0]
5. Stop

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