Shiny中Crosstalk联动Plotly条形图点击仅半条高亮问题求解

该半高亮异常是Plotly与Crosstalk联动时的默认样式适配问题导致：

• Plotly条形图默认包含填充色、描边两层渲染样式，Crosstalk的highlight功能默认仅修改填充色的透明度，未同步调整描边的透明度属性，两种样式叠加后就会出现选中条形仅部分区域高亮的视觉效果。
• Plotly自带的点击选中交互效果和Crosstalk的高亮效果叠加，也会进一步加重显示异常。

在highlight函数中显式指定选中、未选中状态的完整marker样式，同步控制填充和描边的透明度即可解决问题，修改后的代码如下：

library(shiny)
library(crosstalk)
library(plotly)
require(dplyr)

df <- tibble(names = LETTERS[1:5], x = runif(5,10,20), y = runif(5,50,100))

ui <- fluidPage(
  fluidRow(
    column(4, plotlyOutput("outp1")),
    column(4, plotlyOutput("outp2"))
  )
)

server <- function(input, output, session) {
  
  hd <- highlight_key(df, ~names)
  
  output$outp1 <- renderPlotly({
    plot_ly(
      hd,
      x = ~names,
      y = ~x,
      type = "bar",
      source = "p1"
    ) %>% highlight(
      on = "plotly_click", 
      off = "plotly_doubleclick",
      # 统一未选中元素的透明度，填充和描边同步降低
      opacityDim = 0.2,
      # 显式指定选中元素的完整样式，填充和描边均保持完全不透明
      selected = attrs_selected(
        marker = list(
          opacity = 1,
          line = list(opacity = 1)
        )
      )
    )
  })
  
  output$outp2 <- renderPlotly({
    plot_ly(
      hd,
      x = ~names,
      y = ~y,
      type = "bar",
      source = "p2"
    ) %>% highlight(
      on = "plotly_click", 
      off = "plotly_doubleclick",
      opacityDim = 0.2,
      selected = attrs_selected(
        marker = list(
          opacity = 1,
          line = list(opacity = 1)
        )
      )
    )
  })
  
}

shinyApp(ui, server)

如果仍存在显示异常，可在plot_ly的参数中显式定义条形的描边样式，覆盖默认渲染规则：

plot_ly(
  hd,
  x = ~names,
  y = ~x,
  type = "bar",
  source = "p1",
  # 统一设置条形描边样式，避免默认样式干扰
  marker = list(line = list(width = 1, color = "#ffffff"))
)

内容的提问来源于stack exchange，提问作者sedsiv