layout

Provides access to the current outer container's (or page's, if none) dimensions (width and height).

Accepts a function that receives a single parameter, which is a dictionary with keys width and height, both of type length. The function is provided context, meaning you don't need to use it in combination with the context keyword. This is why measure can be called in the example below.

#let text = lorem(30)
#layout(size => [
  #let (height,) = measure(
    block(width: size.width, text),
  )
  This text is #height high with
  the current page width: \
  #text
])

Note that the layout function forces its contents into a block-level container, so placement relative to the page or pagebreaks are not possible within it.

If the layout call is placed inside a box with a width of 800pt and a height of 400pt, then the specified function will be given the argument (width: 800pt, height: 400pt). If it is placed directly into the page, it receives the page's dimensions minus its margins. This is mostly useful in combination with measurement.

You can also use this function to resolve ratio to fixed lengths. This might come in handy if you're building your own layout abstractions.

#layout(size => {
  let half = 50% * size.width
  [Half a page is #half wide.]
})

Note that the width or height provided by layout will be infinite if the corresponding page dimension is set to auto.