Cutting Polyshape using Y function

I need to seperate final object using Y function

Both final object and Y function will be determined by user but i added random input so you dont have to deal with that

There is the simplified code

x1:0
x2:6
y1:0
y2:8
RX1=-190
RX2=149
RY1=111
a=1
f=0
CC=[149,111]
rectangle= polyshape([RX1,RX1,RX2,RX2],[0,RY1,RY1,0]);
triangle = polyshape([RX1,0,RX1],[(RY1-((10*a)+h)),RY1,RY1]);
cirle    = polybuffer(CC,'points',((10*a)+f));
cut      = union(cirle,triangle);
final    = subtract(rectangle,cut);
plot(final)

x1=A(1,1);
y1=A(1,2);
x2=A(2,1);
y2=A(2,2);
m=((y2-y1)/(x2-x1));
Y =@(X) (m*(X-x1)+y1);

Answer 1

[Pavan Sahith]

Hello,

As per my understanding, you have a polyshape and want to separate the 'final' object using a 'Y' function.

To achieve that in MATLAB you can generate the curve using the user-provided function and then cut the polyshape using “intersect” or “subtract”.

Refer to this sample code which defines a rectangle and a 'Y' function, creates a polyshape for the region above the 'Y' function, and then finds the intersection between the rectangle and the region to obtain the 'final' shape.

% Define rectangle and Y function 
RX1 = -190; 
RX2 = 149; 
RY1 = 111; 

rectangle = polyshape([RX1, RX1, RX2, RX2], [0, RY1, RY1, 0]); 
Y = @(X) 0.5*X + 50; 

% Create polyshape for region above Y function 
x = linspace(RX1, RX2, 100); 
y = Y(x); 

% Intersect rectangle and region 
region = polyshape([x, fliplr(x)], [y, ones(size(y))*max(rectangle.Vertices(:,2))]) 
final = intersect(rectangle, region); 

% difference of two polyshape objects. 
final1 = subtract(rectangle, region); 

% Plot result 
plot(final)
plot(final1)

The “fliplr” function is used to flip the order of the elements in an array from left to right.

In this code, it's used to create a closed polygon for the region above the ‘Y’ function by concatenating the original ‘x’ values with their reversed order.

Please refer to the MathWorks documentation to know more about

“intersect”- https://in.mathworks.com/help/matlab/ref/polyshape.intersect.html

“subtract”- https://in.mathworks.com/help/matlab/ref/polyshape.subtract.html

“fliplr”-https://in.mathworks.com/help/matlab/ref/fliplr.html