如何绘制实心圆? [英] How to plot a filled circle?

问题描述

下面的代码在Matlab中绘制圆圈.如何在其中指定MarkerEdgeColor和MarkerFaceColor.

The below code plots circles in Matlab. How can I specify the MarkerEdgeColor and MarkerFaceColor in it.

function plot_model
exit_agents=csvread('C:\Users\sony\Desktop\latest_mixed_crowds\December\exit_agents.csv');
%scatter(exit_agents(:,2),exit_agents(:,3),pi*.25^2,'filled');
for ii =1:size(exit_agents,1),
    circle(exit_agents(ii,2),exit_agents(ii,3),0.25);
end
end
function h = circle(x,y,r)
hold on
th = 0:pi/50:2*pi;
xunit = r * cos(th) + x;
yunit = r * sin(th) + y;
h = plot(xunit, yunit);
hold off
end

在缩放时，使用图和散点会怪异地缩放它们.这不是我想要的.

Using plot and scatter scales them weirdly when zooming. This is not what I wish for.

推荐答案

有 各种选项 绘制圆圈.最简单的方法是实际绘制> 填充的rectangle :

%// radius
r = 2;

%// center
c = [3 3];

pos = [c-r 2*r 2*r];
r = rectangle('Position',pos,'Curvature',[1 1], 'FaceColor', 'red', 'Edgecolor','none')
axis equal

随着 R2014b 图形引擎的更新，这真的很顺畅:

With the update of the graphics engine with R2014b this is really smooth:

如果您使用的Matlab版本低于 R2014b ，则需要坚持使用三角法，但是请使用

If you have an older version of Matlab than R2014b, you will need to stick with your trigonometric approach, but use fill to get it filled:

%// radius
r = 2;
%// center
c = [3 3];
%// number of points
n = 1000;
%// running variable
t = linspace(0,2*pi,n);

x = c(1) + r*sin(t);
y = c(2) + r*cos(t);

%// draw filled polygon
fill(x,y,[1,1,1],'FaceColor','red','EdgeColor','none')
axis equal

分辨率" 可以根据点数n自由缩放.

The "resolution" can be freely scaled by the number of points n.

您的函数将如下所示

function h = circle(x,y,r,MarkerFaceColor,MarkerEdgeColor)
hold on
c = [x y];
pos = [c-r 2*r 2*r];
r = rectangle('Position',pos,'Curvature',[1 1], ...
    'FaceColor', MarkerFaceColor, 'Edgecolor',MarkerEdgeColor)
hold off
end

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