热图。2 (gplot)如何更改颜色键的水平大小并添加一个图例

I am producing heatmaps with heatmap.2. I know how to controls many of the parameters but still I have not found a way of making the key of color only wider or putting it as a strip in a side or bottom of the plot. I am producing heatmaps with heatmap.2. I know