How to use guide_colourbar()?

In this vignette, I’d like to explain how to use guide_colourbar() function to control color bar.

Prerequisite

If you are not familiar with the R package ggplotAssist, please read the following REAME file of the ggplotAssist package.

https://cran.r-project.org/web/packages/ggplotAssist/README.html

Install package

You can install developmental version of ggplotAssist package from github.

#install.packages("devtools")
devtools::install_github("cardiomoon/ggplotAssist")

guide_colourbar() function

You can see help file for guide_colourvar() function by typing ?guide_colourbar in R console. This function has so many arguments.

guide_colourbar(title = waiver(), title.position = NULL,
  title.theme = NULL, title.hjust = NULL, title.vjust = NULL,
  label = TRUE, label.position = NULL, label.theme = NULL,
  label.hjust = NULL, label.vjust = NULL, barwidth = NULL,
  barheight = NULL, nbin = 20, raster = TRUE, ticks = TRUE,
  draw.ulim = TRUE, draw.llim = TRUE, direction = NULL,
  default.unit = "line", reverse = FALSE, order = 0, ...)

Example in R help file

We are going to make this plot.

require(ggplot2)
df <- reshape2::melt(outer(1:4, 1:4), varnames = c("X1", "X2"))
ggplot(df, aes(X1, X2)) + 
    geom_tile(aes(fill = value)) +
    guides(fill = guide_colorbar(barwidth = 0.5, barheight = 10, title="Value"))

Preprocessing

Launch the ggplotAssist Add-in from RStudio. Type the following R code in preprocesing textInput(1).

df <- reshape2::melt(outer(1:4, 1:4), varnames = c("X1", "X2"))

Turn on the preprocessing(2). Enter df as a data name(3). Select x among Aesthetics and select X1 among mapping. And then select y and X2 to make R code for ggplot(5).

Make geom_tile() layer

Select geom among layers(1). Select geom_tile function(2). Select mapping radioButton(3). Select fill among aesthetics(4) and assign value(5). Confirm the R code for layer(6) and press Add Layer button(7).

Adjust guide_colorbar() function

Select guides among layers(1). Select guides function(2). Select fill aesthetics(3). select guide_colorbar among fill selectInput(4). You can see the arguments of the function guide_colourbar()(scarlet rectangle). Enter 0.5 as barwidth(5) and 12 as barheight(6). Enter Value as title(7). You can see the R code for this layer(8).

You can see the plot preview. Please compare colorbars of two figures.

Please do not hesistate to change the arguments of this function guide_colourbar() with your mouse. Happy ggplot!!