Can I have round corners with PATCH?

I use the following to create a rectangular box using PATCH,

patch([7 7 5 5], [5 7 7 5], 'r')
axis([0 10 0 10])

I want round corners. I have tried the property LineJoin but it does not do anything.

h.LineJoin = 'round';

So is this possible?

Answer 1

[Matt J]

You can with polyshape,

h=polybuffer( polyshape([7 7 5 5], [5 7 7 5]),0.5);

plot(h,'FaceColor','r', 'FaceAlpha',0.5)

[Kevin]

Great. Thank you.

Also I can control transparency.

plot(h, 'FaceAlpha', 0.1)

Answer 2

[Les Beckham]

Try this. Adjust the 'curvature' value to adjust the ratio of the round corners to the size of the rectangle (1.0 will result in a circle).

rectangle('position', [5 5 2 2], 'curvature', 0.2, 'facecolor', 'r')
axis equal
axis([0 10 0 10])

[Kevin]

Actually I also want to adjust transparency (i.e. alpha).

I can adjust alpha property with patch but not with rectangle.

[Les Beckham]

Actually, you can. Use a four element color specification. The fourth element is the alpha.

r = rectangle('position', [5 5 2 2], 'curvature', 0.2, 'facecolor', [1 0 0 0.2]);
axis equal
axis([0 10 0 10])

[Kevin]

I see. But the forth element is not mentioned in the DOC.

I am hoping that this is not an undocumented feature and it may get removed in the future.

But thanks for mentioning this. I have learnt something new today. Great.

[Les Beckham]

You are welcome.

I did too! I wasn't aware of polyshape or polybuffer. Apparently those were added during the several years that I didn't have a copy of Matlab.