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Styling and themes

This tutorial deals with styling and configuration in general and on a broader level. The following tutorials give more insight into styling of individual parts of a diagram.

At the end of this tutorial we will be looking into how to create a reusable theme or preset for diagrams. Lilaq ships a few predefined themes.

Elements for styling​

Many components of a diagram, such as title, legend, label, grid and more are element functions. In particular, diagram itself is an element function, enabling powerful customization and an intuitive way of creating themes (see below).

info

Element functions in Typst are functions that can be used with set and show rules.

warning

Since custom element functions (in the future so-called types) are not yet available in Typst, Lilaq uses elembic to provide a powerful workaround. For this reason, instead of

#set lq.diagram(width: 10cm)
#show lq.diagram: set text(0.8em)

for now, we need to write:

#show: lq.set-diagram(width: 10cm)
#show lq.selector(lq.diagram): set text(0.8em)

In the following, we will configure different aspects of a diagram by means of illustrative examples.

Setting the text size​

It is common to use a slightly smaller font size for diagrams compared to the main text, especially in two-column formats. Below, we use a show-set-rule to configure the text size for all diagrams.

#show lq.selector(lq.diagram): set text(.8em)

This will affect all text nodes of the diagram, i.e., the title, axis and tick labels, legend text etc. at once. In order to apply a set rule selectively to just some of these elements, we can address them individually:

#show lq.selector(lq.legend): set text(.8em)
#show lq.selector(lq.tick-label): set text(.8em)

Title and label positions​

Although axis labels and titles are by default all centered, they are designed in a way so that they work nicely with set align() rules.

In the following example, we change the default alignment to top + right for label, so xx-labels are aligned at the right and yy-labels are aligned at the top. Furthermore, we move the title to the right.

#show lq.selector(lq.label): set align(top + right)
#show lq.selector(lq.title): set align(right)

#lq.diagram(
  title: [Title],
  xlabel: $x$,
  ylabel: $y$
)

Creating a custom preset or theme​

Suppose that all of our diagrams will use logarithmic scaling on the xx-axis. We could set this up at the start of the document instead of repeating xscale: "log" for each diagram:

#show: lq.set-diagram(xscale: "log")

#lq.diagram()

This is great, but we might have different types of diagrams in our document and would like to apply these styles only to some plots. This is where presets/themes come into play.

Let's imagine we want to draw a series of spectra, all featuring the same axis labels and a logarithmic yy-scaling. To avoid repeating the same information over and over (and also to make future changes easier), we want to create a reusable preset/theme. This will be just a function that can be used in a document-level show rule for transforming content.

#let spectrum-plot = it => {
  // <- insert set and show rules here
  it
}

To use the theme, we create a scope (to avoid applying the theme to all following plots) and apply the theme with a show rule.

#{
  show: spectrum-plot
  lq.diagram()
}

Let us now fill this theme with some configuration!

#let spectrum-plot = it => {
  show: lq.set-diagram(
    title: [Spectrum], 
    yscale: "log",
    ylabel: [Intensity],
    xlabel: [Wavelength],
    xaxis: (subticks: none)
  )
  show: lq.set-tick(
    outset: 2pt, inset: 0pt
  )
  it
}


#{
  show: spectrum-plot

  lq.diagram(
    lq.plot((1, 3), (1, 100))
  )
}

This is exactly how the built-in themes shipped with Lilaq are constructed.