MATLAB: Question regarding impoly restraint to move about a specified path

impolyMATLAB

Lets say I have an implicit equation in x and y f(x,y)=x^2 + y^2 -5*x +12*y +24 which is an example. I construct an impoly with three or n number of vertices over the curve.My question is how can I restrict the movement of vertices of impoly to be restricted to follow the path of the curve.

Best Answer

Use setPositionConstraintFcn function
function main
clc,clear
x = 0:.05:10;
y = sin(x);
plot(x,y,'.-r')
h = impoly(gca,[0:2; sin(0:2)]');       % create impoly on the curve
setPositionConstraintFcn(h,@fcn)        % assign constraint
    function newPos = fcn(currPos)
        d = pdist2([x(:) y(:)],currPos);
        [~,ix] = min(d);                % find closest points
        newPos = [x(ix); y(ix)]';       % constrained position
    end
end
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