MATLAB中bar3()函数画柱状图时按高度显示颜色

在利用MATLAB的bar3()函数画一个矩阵的柱状图时，如何改变显示的颜色，让它根据数据大小的不同显示不同的颜色，比如数据越大颜色越深，而不是bar3内置的颜色那样沿x轴或y轴渐变。

M=rand(30,20);
figure
subplot(1,2,1)
h=bar3(M);
for n=1:numel(h)
    cdata=get(h(n),'zdata');
    set(h(n),'cdata',cdata,'facecolor','interp')
end

subplot(1,2,2)
h=bar3(M);
for n=1:numel(h)
    cdata=get(h(n),'zdata');
    cdata=repmat(max(cdata,[],2),1,4);
    set(h(n),'cdata',cdata,'facecolor','flat')
end 

Color 3-D Bars by Height

http://cn.mathworks.com/help/matlab/creating_plots/color-3-d-bars-by-height-1.html

This example shows how to modify a 3-D bar plot by coloring each bar according to its height.

Create a 3-D bar graph of data from the magic function. Return the surface objects used to create the bar graph in array b. Add a colorbar to the graph.

Z = magic(5);
b = bar3(Z);
colorbar

For each surface object, get the array of z-coordinates from the ZData property. Use the array to set the CData property, which defines the vertex colors. Interpolate the face colors by setting the FaceColor properties of the surface objects to 'interp'.

Note: Starting in R2014b, you can use dot notation to query and set properties. If you are using an earlier release, use the get and set functions instead, such as zdata = get(b(k),'ZData').

for k = 1:length(b)
    zdata = b(k).ZData;
    b(k).CData = zdata;
    b(k).FaceColor = 'interp';
end

The height of each bar determines its color. You can estimate the bar heights by comparing the bar colors to the colorbar.