# How to clear this plot?

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han han on 22 Jun 2020
Edited: Rik on 22 Jun 2020
As shown in the picture, what about the ellipse in the lower left corner?
My code wants to express that the size of the two ellipses can be changed by myself.
I want to present an ellipse and a regular circle.
xUECenter=5;
yUECenter=5;
a = 3;
b = 3;
r = a;
hEllipse = imellipse(gca,[-a, -b, 2*a, 2*b]);
disp(hEllipse);
xy = hEllipse.getVertices();
axesHandlesToChildObjects = findobj(gca, 'Type', 'line');
if ~isempty(axesHandlesToChildObjects)
delete(axesHandlesToChildObjects);
end
x = xy(:,1);
y = xy(:,2);
xy = [x y];
for k = 1 : length(angles_Panel_0)
theta = angles_Panel_0(k);
rotationArray = [cosd(theta) sind(theta); -sind(theta) cosd(theta)];
rotated_xy = xy * rotationArray;
xCenter2 = xUECenter + (r - 0.25) * cosd(theta);
yCenter2 = yUECenter + (r - 0.25) * sind(theta);
x = rotated_xy(:,1) + xCenter2;
y = rotated_xy(:,2) + yCenter2;
plot(x, y, 'b');
if k == 1
grid on;
hold on;
end
end
hold on;
xNodeCenter=6;
yNodeCenter=6;
a = 3;
b = 0.5;
r = a;
hEllipse1 = imellipse(gca,[-a, -b, 2*a, 2*b]);
xy = hEllipse1.getVertices();
axesHandlesToChildObjects = findobj(gca, 'Type', 'line');
x = xy(:,1);
y = xy(:,2);
xy = [x y];
for k = 1 : length(angles)
theta = angles(k);
rotationArray = [cosd(theta) sind(theta); -sind(theta) cosd(theta)];
rotated_xy = xy1 * rotationArray;
xCenter3 = xNodeCenter + (r - 0.25) * cosd(theta);
yCenter3 = yNodeCenter + (r - 0.25) * sind(theta);
x1 = rotated_xy(:,1) + xCenter3;
y1 = rotated_xy(:,2) + yCenter3;
plot(x1, y1, 'm');
if k == 1
grid on;
hold on;
end
end

Rik on 22 Jun 2020
Edited: Rik on 22 Jun 2020
You should probably make your code into a function instead of copy-pasting it. That would highlight that you didn't define angles_Panel_0 or angles and used xy1 where you probably meant xy.
It would also show you that you forgot to do
delete(hEllipse1)
So the ellipse is still there.
You can use the code below, although you should add documentation for that function, and you should expain what you code is doing with comments.
angles_Panel_0=0;
xUECenter=5;
yUECenter=5;
a = 3;
b = 3;
r = a;
LineSpec='b';
plot_ellipse(a,b,r,xUECenter,yUECenter,angles_Panel_0,LineSpec)
angles=0;
xNodeCenter=6;
yNodeCenter=6;
a = 3;
b = 0.5;
r = a;
LineSpec='m';
hold on;
plot_ellipse(a,b,r,xNodeCenter,yNodeCenter,angles,LineSpec)
hold off;
function plot_ellipse(a,b,r,xNodeCenter,yNodeCenter,angles,LineSpec)
%write documentation here explaing inputs and usage
hEllipse = imellipse(gca,[-a, -b, 2*a, 2*b]); %#ok<IMELLPS>
xy = hEllipse.getVertices();
delete(hEllipse)
x = xy(:,1);
y = xy(:,2);
xy = [x y];
for k = 1 : length(angles)
theta = angles(k);
rotationArray = [cosd(theta) sind(theta); -sind(theta) cosd(theta)];
rotated_xy = xy * rotationArray;
xCenter = xNodeCenter + (r - 0.25) * cosd(theta);
yCenter = yNodeCenter + (r - 0.25) * sind(theta);
x = rotated_xy(:,1) + xCenter;
y = rotated_xy(:,2) + yCenter;
plot(x, y, LineSpec);
if k == 1
grid on;
hold on;
end
end
end