Shiny App clickable points not working with log scale y axis - r

Question

For the first time I really can't find this answer here already, so I hope you all can help me, I'm sure there is a pretty easy fix.
I am making a Shiny volcano plot with clickable points to give me a table with the data about that point. If I use a trans function (that I found here, thank you helpful stranger) within scale_y_continuous() in my plot, points in the scaled region are no longer clickable. How can I scale the axis this way and still be able to have the clickable points?
My code, with some fake data that has the same problem:
## Read in necessary libraries, function, and data
library(shiny)
library(ggplot2)
library(dplyr)
library(scales)
reverselog_trans <- function(base = exp(1)) {
trans <- function(x) -log(x, base)
inv <- function(x) base^(-x)
trans_new(paste0("reverselog-", format(base)), trans, inv,
log_breaks(base = base),
domain = c(1e-100, Inf))
}
pretend_data <- tibble(data=1:5, estimate = runif(5, min = -1, max = 2), plot = c(1e-50, 2e-35, 5e-1, 1, 50))
# Define UI for application that draws a volcano plot
ui <- fluidPage(
# Application title
titlePanel("Pretend Plot"),
plotOutput("plot", click = "plot_click"),
tableOutput("data")
)
# Define server logic required to draw a volcano plot
server <- function(input, output, session) {
output$plot <- renderPlot({
ggplot(data = pretend_data, aes(x=estimate, y=plot)) +
geom_vline(xintercept=c(-1, 1), linetype=3) +
geom_hline(yintercept=0.01, linetype=3) +
geom_point() +
scale_y_continuous(trans = reverselog_trans(10))
}, res = 96)
output$data <- renderTable({
req(input$plot_click)
nearPoints(pretend_data, input$plot_click)
})
}
# Run the application
shinyApp(ui = ui, server = server)

Answer 1

The problem is that input$plot_click returns the coordinates on the transformed scale. nearPoints tries then to match those to the original scale which does not work.
You have a couple of options though:
Transform the data yourself and adapt y axis ticks via scale_y_continuous
Adapt pretend_data in the nearPoints call.
Option 1
This requires that you control y axis tick marks yourself and would need some more fiddling to get the exact same reuslts as in your example.
pretend_data_traf <- pretend_data %>%
mutate(plot = reverselog_trans(10)$transform(plot))
# Define UI for application that draws a volcano plot
ui <- fluidPage(
# Application title
titlePanel("Pretend Plot"),
plotOutput("plot", click = "plot_click"),
tableOutput("data")
)
# Define server logic required to draw a volcano plot
server <- function(input, output, session) {
output$plot <- renderPlot({
ggplot(data = pretend_data_traf, aes(x=estimate, y=plot)) +
geom_vline(xintercept=c(-1, 1), linetype=3) +
geom_hline(yintercept=0.01, linetype=3) +
geom_point() +
## would need to define breaks = to get same tick mark positions
scale_y_continuous(labels = reverselog_trans(10)$inverse)
}, res = 96)
output$data <- renderTable({
req(input$plot_click)
nearPoints(pretend_data_traf, input$plot_click)
})
}
# Run the application
shinyApp(ui = ui, server = server)
Option 2
pretend_data_traf <- pretend_data %>%
mutate(plot = reverselog_trans(10)$transform(plot))
# Define UI for application that draws a volcano plot
ui <- fluidPage(
# Application title
titlePanel("Pretend Plot"),
plotOutput("plot", click = "plot_click"),
tableOutput("data")
)
# Define server logic required to draw a volcano plot
server <- function(input, output, session) {
output$plot <- renderPlot({
ggplot(data = pretend_data, aes(x=estimate, y=plot)) +
geom_vline(xintercept=c(-1, 1), linetype=3) +
geom_hline(yintercept=0.01, linetype=3) +
geom_point() +
scale_y_continuous(trans = reverselog_trans(10))
}, res = 96)
output$data <- renderTable({
req(input$plot_click)
nearPoints(pretend_data_traf, input$plot_click) %>%
mutate(plot = reverselog_trans(10)$inverse(plot))
})
}
# Run the application
shinyApp(ui = ui, server = server)