Configurable font edges ⚙

Adds top-edge and bottom-edge parameters to the font function. These define how
the box around a word is computed. The possible values are:
- ascender
- cap-height (default top edge)
- x-height
- baseline (default bottom edge)
- descender

The defaults are chosen so that it's easy to create good-looking designs with
vertical alignment. Since they are much tighter than what most other software
uses by default, the default leading had to be increased to 50% of the font size
and paragraph spacing to 100% of the font size.

The values cap-height and x-height fall back to ascender in case they are zero
because this value may occur in fonts that don't have glyphs with cap- or
x-height (like Twitter Color Emoji). Since cap-height is the default top edge,
doing no fallback would break things badly.

Removes softness in favor of a simple boolean for pages and a more finegread u8
for spacing. This is needed to make paragraph spacing consume line spacing
created by hard line breaks.

2 files changed, 15 insertions, 1 deletions

diff --git a/tests/typ/library/font.typ b/tests/typ/library/font.typ
index c00bff5a..ecea303f 100644
--- a/tests/typ/library/font.typ
+++ b/tests/typ/library/font.typ
@@ -32,6 +32,20 @@ Emoji: 🐪, 🌋, 🏞
 ]
 
 ---
+// Test top and bottom edge.
+
+#page(width: 170pt)
+#let try(top, bottom) = rect(fill: #9feb52)[
+    #font(top-edge: top, bottom-edge: bottom)
+    `From `#top` to `#bottom
+]
+
+#try(ascender, descender)
+#try(ascender, baseline)
+#try(cap-height, baseline)
+#try(x-height, baseline)
+
+---
 // Ref: false
 
 // Error: 7-12 unexpected argument
diff --git a/tests/typ/library/spacing.typ b/tests/typ/library/spacing.typ
index a34840c6..6d50f0dc 100644
--- a/tests/typ/library/spacing.typ
+++ b/tests/typ/library/spacing.typ
@@ -2,7 +2,7 @@
 
 ---
 // Ends paragraphs.
-Tightly #v(-5pt) packed
+Tightly #v(0pt) packed
 
 // Eating up soft spacing.
 Inv #h(0pt) isible