plot ellipses by clicking points?

How to plot ellipses by clicking on the points. I have a 100*100 cm grid and I would like to generate ellipses in it by clicking different positions. Is there a way to do it? The ellipses can intersect and thereby I need to detect the high region of intersection.

[KSSV]

You want to click and make the center? Do you have minor, major axis data? Or you want to click the entire ellipse?

[Ramesh Bala]

function gridplot

axis([0 100 0 100])

rectangle('Position',[0 0 100 100]) grid on

hold on

X = [10 90 90 20 50 90 40 20 90 ];

Y = [10 10 20 30 50 60 70 80 90 ];

% Create plot plot(X,Y,'MarkerFaceColor',[0.847058832645416 0.160784319043159 0],...

'Marker','o',...

'LineStyle','none',... 'Color',[1 0 0]);

txt1 = ' 7';

text(X(1),Y(1),txt1)

txt2 = ' 2'; text(X(2),Y(2),txt2) txt3 = ' 3';

text(X(3),Y(3),txt3)

txt4 = ' 4'; text(X(4),Y(4),txt4) txt5 = ' 5';

text(X(5),Y(5),txt5)

txt6 = ' 6'; text(X(6),Y(6),txt6) txt7 = ' 1';

text(X(7),Y(7),txt7)

txt8 = ' 8'; text(X(8),Y(8),txt8) txt9 = ' 9';

text(X(9),Y(9),txt9)

xlabel({'Length','(cm)'})

ylabel({'Width', '(cm)'})

ax = gca; ax.XRuler.Axle.LineWidth = 2; ax.YRuler.Axle.LineWidth = 2;

GridLineWidth = 2;

end

This is my code, I would like to select marker points and create ellipses from it.

[Ramesh Bala]

[Ramesh Bala]

whether imellipse or drawellipse works in this case?

[Ramesh Bala]

I believe imellipse is already a preloaded one where one just clicks and drag the ellipse, can it be modified based on the above case?

Answer 1

[KSSV]

figure
hold on
axis equal

t=-pi:0.01:pi;
for i = 1:10
    a=10; % horizontal radius
    b=5; % vertical radius
    [x0,y0] = getpts() ;    
    x=x0(1)+a*cos(t);
    y=y0(1)+b*sin(t);
    plot(x,y)
    drawnow
end

[Ramesh Bala]

Thanks KSSV,I'm expecting to do it in another way with user interface by direct clicks

[KSSV]

Edited answer....double click at a point, when figure is prompted

[Ramesh Bala]

That's interesting good option drawnow ,never knew that.Thanks.But the picture obtained looked like this with varying thickness?

[KSSV]

There is a problem with clicking....you should double click ..fast...edited the code...

[Ramesh Bala]

thanks, lemme have a check.Is there any reason for keeping a,b constant. Can't it be like

a = (x0(1)+x0(2))./2;

b = (y0(1)+y0(2))./2;

or do you have other choices?

[KSSV]

That is your choice..you should be knowing....they determine the size/ radii of ellispes.

[Ramesh Bala]

Thanks for the comments; this is the overall script created. But the problem is that it's moving away from the boundary. Of course, I know it's based on the radii size as we mention, but is there any way to constrain that within boundary ??

function ellipsedrawon

clear

close uiopen

t=-pi:0.01:pi;

for i = 1:20

%getting the points

    [x0,y0] = ginput(2) ;

% a =10;

% b =5;

% a = (x0(1)+x0(2))./2; % horizontal radii

    b = (y0(1)+y0(2))./2; % vertical radii

% x,y ellipse plot

    x=x0(1)+a*cos(t);

    y=y0(1)+b*sin(t);

    plot(x,y)

    drawnow

end