Use a for loop to find out if point B is away from point A by a known amount

I have point A and point B. (In the figure only two pairs of A and B.)

condition: I want to find out if point B is far from point A by an amount between -2 and 2 in the X and Y direction (the -2 and 2 are included).

I need to create a for loop for all points (all rows) of the "sortedmat" matrix so that:

• if the condition is verified, I have to redo the loop.
• if the condition is not verified, I have to save the array with the points that were within the two intervals.

I started in the following way but I don't know how to go about it.

sortedmat = importdata("sortedmat.txt");

positive_distance_X = 2;
negative_distance_X = -2;

positive_distance_Y = 2;
negative_distance_Y = -2;

row_used_A = 1;
% row_used_A = 309;
point_A_direction_X = sortedmat(row_used_A,1);
point_A_direction_Y = sortedmat(row_used_A,2);

row_used_B = row_used_A + 1;
point_B_direction_X = sortedmat(row_used_B,1);
point_B_direction_Y = sortedmat(row_used_B,2);

distance_X_direction = point_B_direction_X - point_A_direction_X;   % must be between negative_distance_X & positive_distance_X
distance_Y_direction = point_B_direction_Y - point_A_direction_Y;   % must be between negative_distance_Y & positive_distance_Y

Answer 1

[Karim]

Hi see below for a demonstration of such a loop.

% load the data
sortedmat = importdata("sortedmat.txt");
% set the allowed delta
delta = 2;
% figure out the number of points
numPoints = size(sortedmat,1);

for i = 1:(numPoints-1)
    
    % get the points we are now looking at
    Point_A = sortedmat(i  ,:);
    Point_B = sortedmat(i+1,:);
    
    % check the condition
    MyCondition = Point_A(1) >= Point_B(1)-delta && Point_A(1) <= Point_B(1)+delta && ...
          Point_A(2) >= Point_B(2)-delta && Point_A(2) <= Point_B(2)+delta;
    
    % if the condition is false, stop the loop
    if ~MyCondition
        break
    end
    
end

% get some info about the result
disp("The first "+num2str(i)+" consecutive points are within a delta of "+num2str(delta)+" pixels")

The first 313 consecutive points are within a delta of 2 pixels

figure
plot(sortedmat(1:i,1),sortedmat(1:i,2),'r')
grid on
title('consecutive points within delta')