Concept:
In raster scan system, electron beam move across the screen one row at a time from top to bottom.
In this, electron beam intensity is turned on and off to produce illumination on the screen.
Explanation:
There are two approaches used in area filling on raster systems: one is scan line algorithm and
another is seed fill algorithm.
1) Scan line algorithm: determine the overlap intervals for scan lines that cross the area or scan
line. A scan line is a line of pixels that are plotted on display device when electron beam scans the
display area horizontally.
2) Seed fill algorithm: It starts from interior position and point outward from this point until the
boundary condition reached. In this, a point is selected and then four or eight connected
approaches is used to fill it.