Hi Jun Zhang,
You can store the face color of each bar in the above figure and then use these color in future plots. As an example, you can use the 'FaceColor' property to extract the color of each bar as follows:
>> y = [2 2 3; 2 5 6; 2 8 9; 2 11 12];
>> h = bar(y);
>> colors = get(h, 'FaceColor');
And then you can set these colors as the FaceColor property of future bar plots.
Hope this helps.
