Scan Line Polygon Fill Algorithm - Raster Graphics

In such algorithm, the information for a solid body is stored in the frame buffer and utilizing that information each pixel that is, of both interior region and boundary are considered and, are so plotted. This time we are going to perform scan conversion of solid regions; here the areas are bounded through polygonal lines.  Pixels are considered for the interior of the polygonal area and are then filled plotted along with the predefined colour. Now let us discuss the algorithm briefly and then we will further discuss details on the similar.

This algorithm checks and modifies the attributes (that is parameters and characteristics) of the pixels only with the current raster scan line. Immediately it crosses over from the outside to the inside of a boundary of the particular polygon it begins resetting the colour or as gray attribute. In filling effect the region along that scans line. Such changes back to the initial attribute while it crosses the boundary again. In following figure, shows variations of this basic idea.

Figure: Concept of scan line polygon filling

Hence as to understand Scan Line Polygon Fill Algorithm in detail consider in following figure:

Figure: Scan line polygon filling