# Introduction to inshiny

`inshiny` provides a basic set of compact Shiny input widgets that are designed to be displayed within surrounding text without breaking the spacing between lines. You can use `inshiny` to integrate Shiny input within text paragraphs, or just to get user input for your Shiny app without taking up as much space on the page compared to standard Shiny inputs.

By default, Shiny uses Bootstrap 3 for layouts and styling. `inshiny` requires Bootstrap 5, which just means that you will need to use the `bslib` package (which enables updating to Bootstrap 5) in addition to `shiny` for `inshiny` to work.

    library(shiny)
    #> Warning: package 'shiny' was built under R version 4.5.2
    library(bslib)
    #> Warning: package 'bslib' was built under R version 4.5.2
    library(inshiny)

To use Bootstrap 5, when building your UI, you should use one of `bslib`’s page layout functions instead of Shiny’s built-in page layouts. In other words, use

- `bslib::page()` instead of `shiny::basicPage()` or `bootstrapPage()`
- `page_fluid()` instead of `fluidPage()`
- `page_fixed()` instead of `fixedPage()`
- `page_fillable()` instead of `fillPage()`
- `page_sidebar()` instead of `sidebarLayout()` within `fluidPage()`
- `page_navbar()` instead of `navbarPage()`.

You should also set a theme using `bslib::bs_theme()`; this allows you to specify `version = 5` so that your app will continue to use Bootstrap 5 even after Bootstrap 6 is released and `bslib` starts to support it. (We may add support for Bootstrap 6 to `inshiny` in the future, but better to make sure your app stays future-proof either way!)

All `inshiny` widgets should be wrapped in a call to `inline()`, which creates a “paragraph” or “line” of text in which you can mix in widgets and arbitrary HTML elements. You can then use widgets such as `inline_text()` or `inline_slider()` within this element. Here is a simple demo of a Shiny UI that uses most of the widgets provided by `inshiny`:

    ui <- page_fixed(
        theme = bs_theme(version = 5, preset = "quartz"),

        h1("Temperature plot"),

        plotOutput("plot", width = 480, height = 320),

        br(),

        inline("Start on ", inline_date("start_date", "2025-01-01"),
            " and plot for ", inline_number("num_days", 365), " days."),

        inline("Average temperature: ", inline_slider("avg_temp", 20, 0, 40),
            " °C. Range: ±", inline_select("temp_range", c(5, 10, 15), 10), " °C."),

        inline("Hemisphere: ", inline_switch("southern", FALSE,
            on = "Southern", off = "Northern")),

        inline(inline_button("colour", "Change colour"), " ",
            inline_link("reset", "Reset"))
    )

The page starts with a title (`h1`) and a `shiny::plotOutput()` that we’ll use to plot average temperatures according to the settings below. There’s a line break (`br`) to space things out, then four `inline` lines containing the `inline_*` widgets provided by `inshiny`. It looks something like this:

Compare this to a similar layout with basic Shiny inputs:

    ui <- page_fixed(
        theme = bs_theme(version = 5, preset = "quartz"),

        h1("Temperature plot"),

        plotOutput("plot", width = 480, height = 320),

        br(),

        dateInput("start_date", "Start date", "2025-01-01"),
        numericInput("num_days", "Number of days", 365),
        sliderInput("avg_temp", "Average temperature (°C)", 0, 40, 20),
        selectInput("temp_range", "Temperature range (± °C)", c(5, 10, 15), 10),
        checkboxInput("southern", "Southern hemisphere", FALSE),
        actionButton("colour", "Change colour"),
        actionLink("reset", "Reset"),
    )

The controls for this version take up far more space:

Of course, you could save some vertical space by laying out the elements in a grid, but they are still rather large compared to the `inshiny` widgets.

We complete the app using server code to handle the inputs:

    server <- function(input, output, session)
    {
        output$plot <- renderPlot({
            date <- input$start_date + seq_len(input$num_days) - 1;
            xpts <- as.POSIXlt(date)$yday; # day number, 0-365
            temperature <- cos(2 * pi * xpts / 364) *
                ifelse(input$southern, 1, -1) * as.numeric(input$temp_range) +
                input$avg_temp;
            oldpar <- par(mar = c(5, 5, 1, 2))
            plot(date, temperature, type = "l", ylim = c(-15, 55),
                col = input$colour %% 16 + 1, lwd = 3)
            abline(h = 0, col = 8, lty = 2)
            par(oldpar)
        })

        observeEvent(input$reset, {
            update_inline("start_date", value = "2025-01-01")
            update_inline("num_days", value = 365)
            update_inline("avg_temp", value = 20)
            update_inline("temp_range", value = "10")
            update_inline("southern", value = FALSE)
        })
    }

This illustrates the use of `update_inline()` to reset the widgets to their original values. You would then launch the app with `shinyApp(ui, server)`.