hsv two way colour ramp

gistfile1.txt

#load packages
require(raster)
require(colorplaner)
require(ggplot2)


#here's some dummy data
r1<- raster(ncol=10, nrow=10)
set.seed(0)
values(r1) <- runif(ncell(r1))
r2<- raster(ncol=10, nrow=10)
values(r2) <- runif(ncell(r2))

#here I create a grid with which I can  extract information on the raster datasets
grid<-raster(ncol=10, nrow=10)
grid[] <- 1:ncell(grid)
grid.pdf<-as(grid, "SpatialPixelsDataFrame")
grid.pdf$r1<-(extract(r1,grid.pdf))
grid.pdf$r2<-(extract(r2,grid.pdf))

#here I convert the grid to a dataframe for plotting in ggplot2
grid.df<-as.data.frame(grid.pdf)
ggplot(data=grid.df,aes(x,y,fill=r1,fill2=r2))+geom_raster()+scale_fill_colourplane("")


# hsv
# Position along diagonal is value
# Distance from the diagonal is saturation
# upper triangle or lower triangle is hue.

col_func <- function(x, y, hue1 = 0.3, hue2 = 0.8, light_grey = 0, dark_grey = 1){
  
  x[x == 0] <- 0.000001
  y[y == 0] <- 0.000001
  x[x == 1] <- 0.999999
  y[y == 1] <- 0.999999
  
  # upper or lower triangle?
  u <- y > x
  hue <- ifelse(u, hue1, hue2)
  
  
  # distace from (0,0) to (x,y)
  hyp <- sqrt(x^2 + y^2) 
  
  # Angle between x axis and line to our point
  theta <- asin(y / hyp)
  
  # Angle between 45 degree line and (x,y)
  phi <- ifelse(u, theta - pi/4, pi/4 - theta)
  phi <- ifelse(phi < 0, 0, phi)
  
  # Distance from 45 degree line and (x,y)
  s <- hyp * sin(phi) / sqrt(2)
  
  # Draw line from (x, y) to 45 degree line that is at right angles.
  # How far along 45 degree line, does that line join.
  v <- (hyp * cos(phi) / sqrt(2))
  scaled_v <- v * (dark_grey - light_grey) + light_grey
  # Get hsv values.
  sapply(seq_along(x), function(i) hsv(hue[i], s[i], scaled_v[i]))
  
}



ggplot(data=grid.df,aes(x,y,fill=r1,fill2=r2))+
  geom_raster()+
  scale_fill_colourplane(name = "",
                         na.color = "white",
                         color_projection = col_func,
                         limits_y = c(0,1),limits=c(0,1),
                         hue1 = 0.5, hue2 = 0.1,
                         dark_grey = 0.8,
                         light_grey = 0.2)