Initial code

src/lib.typ

@@ -0,0 +1,91 @@
+#import calc
+
+#let font-size = 11pt
+#let lead = 13pt
+
+/* This calculates the number of lines that fit on a page, ensuring that
+bottom floating figures line up with the last line on the page.
+You could have Typst calculate all of this, but unfortunately
+it cuts off the result 2 digits after the decimal. */
+#context {
+  let smaller-edge = calc.min(page.width, page.height)
+  let y = calc.floor((page.height - (2 * smaller-edge * 2.5 / 21)) / lead)
+  [Set `margin-y` to $ (page.height - #y dot.c #lead) / 2
+  approx #((page.height - y * lead)/2) . $
+  Typst is not accurate enough, please calculate it yourself.]
+}
+#let margin-y = 76.445pt
+
+#set page(
+  margin: (y: margin-y),
+)
+#set par(
+  leading: 0pt,
+  first-line-indent: lead,
+  justify: true,
+  // spacing: 0pt // Uncomment this property or set it in your main source file
+                  // ONLY if you’re on the web app or the main branch.
+                  // Don’t if you’re using the release version.
+)
+#set text(
+  top-edge: lead,
+  size: font-size
+)
+
+#set block(spacing: 0pt)
+#show quote.where(block: true): set block(spacing: lead)
+
+/* Wrapper function.
+Measures the size of its argument, calculates the appropriate spacing,
+and applies it using the `pad` function. */
+#let a(it) = context[#layout(size => [
+  #let (height,) = measure(
+    block(width: size.width, it),
+  )
+  #let pos = here().position().y
+  #let padding = lead
+  #while height > padding {
+    padding += lead
+  }
+  #if pos == margin-y [
+    #pad(bottom: (padding + lead - height), it)
+  ] else [
+    #pad(y: (padding - height + (2 * lead)) / 2, it)
+  ]
+])]
+
+/* Floats don’t work correctly when using `layout`, so we calculate
+the height of these another way. They don’t need a wrapper function,
+we’re directly applying the spacing via show rules. */
+#let float-adjustment(it) = context {
+  let body-size = measure(it.body).height
+
+  /* Unfortunately we can’t accurately measure images wider than the text column,
+  so we need to tell the user to manually set the figure body’s width. */
+  if it.kind == image {
+    layout(size => {
+      let container-width = size.width
+
+      let body-width = measure(it.body).width
+      assert(
+        body-width <= container-width,
+        message: str("Set the image's width to <=" + str(container-width/1pt) + "pt.")
+      )
+    })
+  }
+  assert(it.caption != none, message: "Please add a caption to your figure.")
+  let caption-size = measure(it.caption).height
+  let height = body-size + figure.gap.to-absolute() + caption-size
+
+  let padding = lead
+  while height > padding {
+    padding += lead
+  }
+  set place(clearance: padding - height + lead)
+
+  it
+}
+
+#show figure.where(placement: top): float-adjustment
+#show figure.where(placement: bottom): float-adjustment
+#show figure.where(placement: auto): float-adjustment