Fills area of canvas with current fill color starting at point [X, Y] and coloring its neighbors.

public procedure FloodFill(X: Integer; 
                           Y: Integer; 
                           BoundaryFillMode: Boolean = False);

Default flood fill mode changes color of all neighbors with the same color as pixel [X, Y]. With BoundaryFillMode set to True neighbors are recolored regardless of their old color, but area which will be recolored has boundary (specified by current pen color).