遮蔽曲线所包围的区域 [英] Shading an area boundered by a curve

问题描述

例如，在曲线y = x ^ 2下方的plot()中，对阴影(或阴影；或与其他阴影不同的任何东西)进行着色的最简单方法是什么?

What would be the easiest way to lightly shade (or hatch; or anything to set it different from the rest) an area in a plot(), below a curve y=x^2, for example ?

x = 0:pi/10:2*pi;  
y = x.^2.;
plot(x,y);

推荐答案

area(x,y) should do the trick. I'm not sure if that class has a FaceAlpha property though.

编辑:不幸的是，区域类没有FaceAlpha属性.但是您可以解决该问题并直接编辑补丁:

Unfortunately, the area class doesn't have a FaceAlpha property. But you can work around that and edit the patch directly:

x=0:pi/10:2*pi;
y=x.^2;
H=area(x,y);
h=get(H,'children');
set(h,'FaceAlpha',0.5); %#Tada!

EDIT2 :要对曲线上方的区域进行阴影处理，可以使用带有白色填充的第二个区域图.这有点像鞭打，但它应该起作用.重新开始:

To shade the area above the curve, you could use a second area plot with a white fill. It's kind of a kludge, but it should work. Starting over:

x=0:pi/10:2*pi;
y=x.^2;
y2=max(y)*ones(size(y));
hold on
H1=area(x,y2);
H2=area(x,y);
set(H2,'FaceColor',[1 1 1]);
axis tight

或基于Jason S的解决方案，使用baseval输入在曲线上方绘制阴影:

or building on Jason S's solution, use the baseval input to shade above the curve:

x=0:pi/10:2*pi;
y=x.^2;
baseval=max(y);
H=area(x,y,baseval);
h=get(H,'children');
set(h,'FaceAlpha',0.5,'FaceColor',[0 1 0]);
axis tight

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