feat: ensure min/max height args on value_box() and column layouts

NEWS.md

@@ -34,6 +34,8 @@
 
 * We increased the spacing between elements just slightly in the Shiny preset. This change is most noticeable in the `layout_columns()` or `layout_column_wrap()` component. In these and other components, you can use `gap` and `padding` arguments to choose your own values, or you can set the `$bslib-spacer` (Sass) or `--bslib-spacer` (CSS) variable. (#998)
 
+* `value_box()`, `layout_columns()` and `layout_column_wrap()` now all have `min_height` and `max_height` arguments. These are useful in filling layouts, like `page_fillable()`, `page_sidebar(fillable = TRUE)` or `page_navbar(fillable = TRUE)`. For example, you can use `layout_columns(min_height = 300, max_height = 500)` to ensure that a set of items (likely arranged in a row of columns) are always between 300 and 500 pixels tall. (#1016)
+
 ## Bug fixes
 
 * `layout_columns()` now always uses a 12-unit grid when the user provides an integer value to `col_widths` for any breakpoint. For example, `breakpoints(md = 3, lg = NA)` will pick a best-fitting layout for large screen sizes using the 12-column grid. Previously, the best fit algorithm might adjust the number of columns as a shortcut to an easy solution. That shortcut is only taken when an auto-fit layout is requested for every breakpoint, e.g. `col_widths = breakpoints(md = NA, lg = NA)` or `col_widths = NA`. (#928)

R/layout.R

@@ -37,6 +37,10 @@
 #' @param fillable Whether or not each element is wrapped in a fillable container.
 #' @param height_mobile Any valid CSS unit to use for the height when on mobile
 #'   devices (or narrow windows).
+#' @param min_height,max_height The maximum or minimum height of the layout container.
+#'   Can be any valid [CSS unit][htmltools::validateCssUnit] (e.g.,
+#'   `max_height="200px"`). Use these arguments in filling layouts to ensure that a
+#'   layout container doesn't shrink below `min_height` or grow beyond `max_height`.
 #' @inheritParams card
 #' @inheritParams card_body
 #'
@@ -74,6 +78,8 @@ layout_column_wrap <- function(
   fillable = TRUE,
   height = NULL,
   height_mobile = NULL,
+  min_height = NULL,
+  max_height = NULL,
   gap = NULL,
   class = NULL
 ) {
@@ -137,7 +143,9 @@ layout_column_wrap <- function(
       # doesn't get inherited in a scenario like layout_column_wrap(height=200, ..., layout_column_wrap(...))
       "--bslib-grid-height" = validateCssUnit(height %||% "auto"),
       "--bslib-grid-height-mobile" = validateCssUnit(height_mobile %||% "auto"),
-      gap = validateCssUnit(gap)
+      gap = validateCssUnit(gap),
+      min_height = validateCssUnit(min_height),
+      max_height = validateCssUnit(max_height)
     ),
     !!!attribs,
     children,
@@ -252,7 +260,9 @@ layout_columns <- function(
   fillable = TRUE,
   gap = NULL,
   class = NULL,
-  height = NULL
+  height = NULL,
+  min_height = NULL,
+  max_height = NULL
 ) {
   args <- separate_arguments(...)
   attribs <- args$attribs
@@ -274,6 +284,8 @@ layout_columns <- function(
     style = css(
       height = validateCssUnit(height),
       gap = validateCssUnit(gap),
+      min_height = validateCssUnit(min_height),
+      max_height = validateCssUnit(max_height)
     ),
     # We don't enable the next option by default, but users could add this
     # attribute to hide the internal elements until after the custom element

R/value-box.R

@@ -55,9 +55,11 @@
 #'   `"text-light"`) to customize the background/foreground colors.
 #' @param fill Whether to allow the value box to grow/shrink to fit a fillable
 #'   container with an opinionated height (e.g., `page_fillable()`).
-#' @param max_height The maximum height of the value box or the showcase area.
-#'   Can be any valid [CSS unit][htmltools::validateCssUnit] (e.g.,
-#'   `max_height="200px"`).
+#' @param max_height The maximum height of the `value_box()` or the showcase
+#'   area when used in a `showcase_layout_*()` function. Can be any valid [CSS
+#'   unit][htmltools::validateCssUnit] (e.g., `max_height="200px"`).
+#' @param min_height The minimum height of the values box. Can be any valid [CSS
+#'   unit][htmltools::validateCssUnit] (e.g., `min_height="200px"`).
 #' @inheritParams card
 #' @param theme_color `r lifecycle::badge("deprecated")` Use `theme` instead.
 #'
@@ -97,6 +99,7 @@ value_box <- function(
   theme = NULL,
   height = NULL,
   max_height = NULL,
+  min_height = NULL,
   fill = TRUE,
   class = NULL,
   id = NULL,
@@ -163,6 +166,7 @@ value_box <- function(
     full_screen = full_screen,
     height = height,
     max_height = max_height,
+    min_height = min_height,
     fill = fill,
     style = css(
       color = theme$fg,