Not able to show Regression Line Equation using ggplotly #1687

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1. cpsievert commented on Feb 4, 2020

   

   cpsievert

   on Feb 4, 2020

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   Added to #566
2. cpsievert

   closed this as completedon Feb 4, 2020
3. aphalo commented on Jun 24, 2023

   

   aphalo

   on Jun 24, 2023

   Last edited by aphalo

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   Layer function stat_poly_equation() is flexible enough to work with 'ggplotly' if some defaults are overriden. One needs to be careful about the positioning of the text labels as some manual tweaking is required.

   library(ggplot2)
   library(ggpmisc)
   library(plotly)

   df <- data.frame(x = c(1:100))
   df$y <- 2 + 3 * df$x + rnorm(100, sd = 40)

   The geom used by default is geom_text_npc() from 'ggpp', which is unknown to 'ggplotly', so we need to use geom_text() instead. 'ggplotly' does not seem to understand character strings that are meant to be parsed into expressions or even respect justification in geom_text(). However, there are workarounds available for all these limitations. The pure-text labels lack italics and super- and subscripts, as stat_poly_eq() currently uses the ASCII character set for equations formatted with output.type = "text".

   my.formula <- y ~ x
   p <-
     ggplot(data = df, aes(x = x, y = y)) +
     geom_smooth(method = "lm", se=FALSE, color="black", formula = my.formula) +
     stat_poly_eq(geom = "text", # override default "text_npc"
                          output.type = "text",  # override default "expression"
                          formula = my.formula,
                          aes(label = paste(..eq.label.., ..rr.label.., sep = ",  ")), # use for sep plain text
                          label.x = 20) + # override default "left"
     geom_point()
   
   ggplotly(p)

   This PNG is downloaded from the plotly plot.

   
4. aphalo commented on Jun 24, 2023

   

   aphalo

   on Jun 24, 2023

   Last edited by aphalo

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   @cpsievert I think the best way to enhance 'ggplotly' would be to implement support for geom_richtext() from package 'ggtext'.