how to use a polybuffer without changing the polygon's shape?

I've used polybuffer. but when the d(distance) is a largen number, the buffer is someting like circle(round).

so I used sqaure too, but it retunred hexagon, not a rectangular even i made a polygon with 4 coordinates.

This is what i want. I want the polybuffer to be as same shape as a polygon.

Thanks.

Answer 1

[Matt J]

use scale

[Sierra]

I tried scale. but unfortunately the result is not what i wanted.

I want to use polybuffer like second image.

Thanks Matt J

[Matt J]

In what way is the result "not what you wanted" and what code produced that result? If you want the expansion centered around the centroid of the polyshape, specify a 3rd argument to the scale() command.

p=nsidedpoly(4);

[cx,cy]=centroid(p);

p(2)=scale(p,2,[cx,cy]);

plot(p)