getgoodsubrect

GETGOODSUBRECT extracts a grid subset of the input grid such that the output grid does not contain any bad points.
 
 GETGOODSUBRECT takes as input a MxNx2 matrix acting a chessboard grid.
 It also takes two vectors containing the x and y coordinates of the bad
 points. The two vectors must be the same size.
 
 The result returned is suboptimal. Optimal algorithms introduce
 complexity beyond our basic requirements.
 
 USAGE:
     gridout=getgoodsubrect(grid,badptsx,badptsy);
 
 INPUTS:
     grid: MxNx2 chessboard grid
 
     badptsx: x coordinates of the bad points
 
     badptsy: y coordinates of the bad points
 
 OUTPUTS:
     gridout: a subset of the input grid without any bad points

0001 function gridout=getgoodsubrect(grid,badptsx,badptsy)
0002 %GETGOODSUBRECT extracts a grid subset of the input grid such that the output grid does not contain any bad points.
0003 %
0004 % GETGOODSUBRECT takes as input a MxNx2 matrix acting a chessboard grid.
0005 % It also takes two vectors containing the x and y coordinates of the bad
0006 % points. The two vectors must be the same size.
0007 %
0008 % The result returned is suboptimal. Optimal algorithms introduce
0009 % complexity beyond our basic requirements.
0010 %
0011 % USAGE:
0012 %     gridout=getgoodsubrect(grid,badptsx,badptsy);
0013 %
0014 % INPUTS:
0015 %     grid: MxNx2 chessboard grid
0016 %
0017 %     badptsx: x coordinates of the bad points
0018 %
0019 %     badptsy: y coordinates of the bad points
0020 %
0021 % OUTPUTS:
0022 %     gridout: a subset of the input grid without any bad points
0023 
0024 
0025 xmin=1;
0026 xmax=size(grid,1);
0027 ymin=1;
0028 ymax=size(grid,2);
0029 
0030 for i=1:length(badptsx)
0031     dist=[badptsx(i)-1,badptsy(i)-1,size(grid,1)-badptsx(i),size(grid,2)-badptsy(i)];
0032     [minval,minindx]=min(dist);
0033     switch minindx
0034         case 1
0035             if badptsx(i)>=xmin
0036                 xmin=badptsx(i)+1;
0037             end
0038         case 2
0039             if badptsy(i)>=ymin
0040                 ymin=badptsy(i)+1;
0041             end
0042         case 3
0043             if badptsx(i)<=xmax
0044                 xmax=badptsx(i)-1;
0045             end
0046         case 4
0047             if badptsy(i)<=ymax
0048                 ymax=badptsy(i)-1;
0049             end
0050     end
0051 end
0052 
0053 gridout=grid(xmin:xmax,ymin:ymax,:);