具有透明度的重叠条形图答案

【问题标题】：Overlap bar charts with transparency具有透明度的重叠条形图
【发布时间】：2015-10-02 11:07:39
【问题描述】：

我创建了两个图表，如下所示。我想将它们一起显示在一个图表上，条形具有一定的透明度，以便两个系列都可见。如何做到这一点（如果有帮助，我可以使用 ggplot）？

widths1 = c(0.023,0.0507,0.0107,0.1148,0.0623,0.0173,0.0083,0.0189,0.0409,0.072,0.0341,0.0125,0.1083,0.0379,0.0504,0.1426,0.0372,0.0713,0.0932,0.0424,0.0822,0.0511)
heights1 = c(5.1,7.5,8.4,8.5,9.2,10.4,12.4,12.5,13.3,13.8,14.6,15.1,15.8,17.2,17.6,18,19.4,20.1,21,21.4,24.3,26)

widths2 = c(0.0716,0.0205,0.0568,0.0658,0.0261,0.0611,0.0313,0.0654,0.0644,0.0294,0.0448,0.0306,0.031,0.0454,0.0891,0.0181,0.0883,0.0765,0.0336,0.0396,0.0315,0.0227,0.0604,0.0394,0.0545)
heights2 =  c(8.3,9.7,11.5,11.8,13.8,14.3,15,15.4,15.8,16.5,17.1,17.1,18.1,19.9,19.9,20.4,21.2,21.6,21.8,24,24.5,24.9,26.6,28.2,29.9)

barplot(heights1, widths1, space=0, col=c("blue"))
barplot(heights2, widths2, space=0, col=c("red"))

所以我怀疑两个条出现的区域都是紫色的。

注意：我见过类似 here 的东西，看起来与我所追求的很接近，但我不确定如何使其适应我的用例（该示例中的图表显示计数，而我想要显示高度系列的值）。

【问题讨论】：

标签： r plot transparency bar-chart

【解决方案1】：

您可以使用rgb 的alpha 参数来创建具有透明度的颜色。在barplot 中额外使用add=TRUE 将条形图添加到现有的：

blue <- rgb(0, 0, 1, alpha=0.5)
red <- rgb(1, 0, 0, alpha=0.5)

barplot(heights1, widths1, space=0, col=blue)
barplot(heights2, widths2, space=0, col=red, add=TRUE)

【讨论】：