Author: Benjamin Guiastrennec

# Plots with multiple pages

#### Benjamin Guiastrennec

#### 02 March, 2026

# Bases of plot faceting

Panels (or faceting) can be created by using the `facets` argument as follows:

- If `facets` is a string e.g `facets = "SEX"`, facets will be created using `ggforce::``facet_wrap_paginate`
- If `facets` is a formula e.g `facets = SEX~MED1`, facets will be created using `ggforce::``facet_grid_paginate`

    # Example with a string
    dv_vs_ipred(xpdb, facets = c('SEX', 'MED1'))

    # Example with a formula
    dv_vs_ipred(xpdb, facets = SEX~MED1, margins = TRUE)

All xpose plot functions accept arguments for `facet_wrap_pagninate` and `facet_grid_paginate` (e.g. `ncol = 2`, `labeller = 'label_both'`, etc.). With the default xpose theme scales are set to `'free'` from one panel to another (`scales = 'free'`), this behavior can be changed with `scales = 'fixed'`, `'free_y'` or `'free_x'`.

# Faceting over multiple pages

## Setting the layout

When the arguments `ncol` and `nrow` are set and under the condition that they are more panels to be drawn that can fit on a single page given the selected layout, the multiple page functionality will automatically be enabled.

    dv_vs_ipred(xpdb, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1)

## Selecting pages

By default all pages will be shown but this can be time consuming. To select only specific pages to be drawn, use the argument `page`.

    dv_vs_ipred(xpdb, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1, page = 1)

It is also possible to change the page(s) to be drawn from an already existing `xpose_plot` object via the `print()` function.

    # Create an xpose_plot, by default page = 1
    p1 <- dv_vs_ipred(xpdb, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1)

    # Change the page to be drawn
    print(p1, page = 2)

## Numbering pages

To number pages the keywords `@page` and `@lastpage` can be used to respectively indicate the current page and the total number of pages.

    dv_vs_ipred(xpdb, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1, page = 1, caption = 'Page @page of @lastpage')

To systematically number all generated plots a caption suffix can be defined in the `xp_theme`.

    xpdb_numbered <- update_themes(xpdb, xp_theme = list(caption_suffix = ', page @page of @lastpage'))

    dv_vs_ipred(xpdb_numbered, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1, page = 2)

# Saving multiple pages plots

Multiple pages graphs can simply be saved by using the `xpose_save()` function.

    dv_vs_ipred(xpdb_numbered, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1) %>%
    xpose_save(file = 'dv_vs_ipred_multiple.pdf')

The `pdf` format can conveniently store multiple pages within a single document. However other graphical devices (e.g. `'png'`, `'jpg'`) can also be used, simply ensure to have a page counter (i.e. `'%03d'`) added the file name.

    dv_vs_ipred(xpdb_numbered, facets = c('SEX', 'MED1'), ncol = 2, nrow = 1) %>%
    xpose_save(file = '@run_@plotfun_%03d.png')