Legend for multi surface plot with specific colors
问题 Take the example for plot_ly function: library("plotly") z <- c( c(8.83,8.89,8.81,8.87,8.9,8.87), c(8.89,8.94,8.85,8.94,8.96,8.92), c(8.84,8.9,8.82,8.92,8.93,8.91), c(8.79,8.85,8.79,8.9,8.94,8.92), c(8.79,8.88,8.81,8.9,8.95,8.92), c(8.8,8.82,8.78,8.91,8.94,8.92), c(8.75,8.78,8.77,8.91,8.95,8.92), c(8.8,8.8,8.77,8.91,8.95,8.94), c(8.74,8.81,8.76,8.93,8.98,8.99), c(8.89,8.99,8.92,9.1,9.13,9.11), c(8.97,8.97,8.91,9.09,9.11,9.11), c(9.04,9.08,9.05,9.25,9.28,9.27), c(9,9.01,9,9.2,9.23,9.2), c(8.99