R: ggplot better gradient color

Question

I am using ggplot to plot Proportional Stacked Bar plot. And the Plot I am getting is something like this:

Answer 1

Borrowing some code from @SimonO101

library(ggplot2)
library(reshape2)
library(RColorBrewer)
mypal <- colorRampPalette( brewer.pal( 9 , "Set1" ) ) #you can try using different palete instead
#of "Set1" until it looks good to you

intercalate <- function(n){ #my crude attempt to shuffle the colors
  c(rbind(1:(n/2), n:(n/2+1))) #it will only work for even numbers
}

PropBarPlot<-function(df, mytitle=""){
  melteddf<-melt(df, id=names(df)[1], na.rm=T)
  ggplot(melteddf, aes_string(x=names(df)[1], y="value", fill="variable")) + 
    geom_bar(position="fill") + 
    theme(axis.text.x = element_text(angle=90, vjust=1)) + 
    labs(title=mytitle)+
    scale_fill_manual( values = mypal(8)[intercalate(8)] )
  #better would be to calculate the different number of categories
  #you have and put that instead of the number 8
}

df <- data.frame(id=letters[1:3],
                 val0=1:3,
                 val1=4:6,
                 val2=7:9, 
                 val3=2:4, 
                 val4=1:3, 
                 val5=4:6, 
                 val6=10:12, 
                 val7=12:14)

print(PropBarPlot(df))

See if that works better for your needs.