29-09-2016, 09:43 AM
POLYGON FILLING
Polygon filling is the process of filling the area of a polygon either completely or by some desire pattern.
Completely filling or colouring the polygon is called solid filling.
Filling the polygon by some desire pattern is known as Pattern Filling.
The area of a polygon is describes as the total number of pixels . It contains by the bounding that outline the filling can be done in boundary or interior region , Hance the colouring of boundary and pattern algorithm is called Boundary fill or floodfill algorithm.
FLOOD FILL ALGORITHM
• Flood fill colors an entire area in an enclosed figure through interconnected pixels using a single color. It is an easy way to fill color in the graphics. One just takes the shape and starts flood fill. The algorithm works in a manner so as to give all the pixels inside the boundary the same color leaving the boundary and the pixels outside.
• Flood fill algorithm is used for filling the interior of a polygon .
• Used when an area defined with multiple color boundaries
• Start at a point inside a region− Replace a specified interior color (old color) with fill color
• Fill the 4−connected or 8−connected region until all interior points being replaced.
4−CONNECTED REGIONS
From a given pixel, the region that you can get to by a series of 4 way moves (north, south, east, west)
8−CONNECTED REGIONS
From a given pixel, the region that you can get to by a series of 8-way moves (north, south, east, west, NE, NW, SE, SW)
Cinque Terre
ADVANTAGE
• Flood fill algorithm is simplest algorithm.
DISADVANTAGE
• Flood fill algorithm is slow.
• For large polygon flood fill algorithm is fail because it requires a large frame.
BOUNDARY FILL ALGORITHM
• In boundary fill algirithm area gets colored with pixels of a chosen color as boundary this giving the technique its name.
• Boundary fill fills the chosen area with a color until the given colored boundary is found.
• Boundary fill algorithm is also called SEED FILLAlgorithm.
• In boundary fill algorithm Recursive method is used to fill the whole boundary .
• Start at a point inside a region
• Paint the interior outward toward the boundary
• The boundary is specified in a single color
• Fill the 4−connected or 8−connected region