Add `math.stretch` element function (#5030)

9 files changed, 72 insertions, 0 deletions

diff --git a/tests/ref/math-stretch-attach-nested-equation.png b/tests/ref/math-stretch-attach-nested-equation.png
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index 00000000..5ab4fbb5
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+++ b/tests/ref/math-stretch-attach-nested-equation.png
diff --git a/tests/ref/math-stretch-attach.png b/tests/ref/math-stretch-attach.png
new file mode 100644
index 00000000..179281a5
--- /dev/null
+++ b/tests/ref/math-stretch-attach.png
diff --git a/tests/ref/math-stretch-basic.png b/tests/ref/math-stretch-basic.png
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index 00000000..3144b11f
--- /dev/null
+++ b/tests/ref/math-stretch-basic.png
diff --git a/tests/ref/math-stretch-complex.png b/tests/ref/math-stretch-complex.png
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index 00000000..be694b71
--- /dev/null
+++ b/tests/ref/math-stretch-complex.png
diff --git a/tests/ref/math-stretch-horizontal.png b/tests/ref/math-stretch-horizontal.png
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index 00000000..9b30be59
--- /dev/null
+++ b/tests/ref/math-stretch-horizontal.png
diff --git a/tests/ref/math-stretch-nested.png b/tests/ref/math-stretch-nested.png
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index 00000000..4583cab9
--- /dev/null
+++ b/tests/ref/math-stretch-nested.png
diff --git a/tests/ref/math-stretch-shorthand.png b/tests/ref/math-stretch-shorthand.png
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index 00000000..59db832a
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+++ b/tests/ref/math-stretch-shorthand.png
diff --git a/tests/ref/math-stretch-vertical.png b/tests/ref/math-stretch-vertical.png
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index 00000000..1f60506d
--- /dev/null
+++ b/tests/ref/math-stretch-vertical.png
diff --git a/tests/suite/math/stretch.typ b/tests/suite/math/stretch.typ
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index 00000000..e6817ee5
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+++ b/tests/suite/math/stretch.typ
@@ -0,0 +1,72 @@
+// Test math stretch.
+
+--- math-stretch-basic ---
+// Test basic stretch.
+$ P -> Q stretch(->, size: #200%) R \
+  R stretch(->) S stretch(->, size: #50%)^"epimorphism" T $
+
+--- math-stretch-complex ---
+// Test complex stretch.
+$ H stretch(=)^"define" U + p V \
+  x stretch(harpoons.ltrb, size: #3em) y
+    stretch(\[, size: #150%) z \
+  f : X stretch(arrow.hook, size: #150%)_"injective" Y \
+  V stretch(->, size: #(100% + 1.5em))^("surjection") ZZ $
+
+--- math-stretch-attach ---
+// Test stretch interactions with attachments.
+#set page(width: auto)
+
+$stretch(stretch(=, size: #4em))_A$
+$stretch(arrow.hook, size: #5em)^"injective map"$
+$stretch(arrow.hook, size: #200%)^"injective map"$
+
+$ P = Q
+    stretch(=)^(k = 0)_(forall i) R
+    stretch(=, size: #150%)^(k = 0)_(forall i) S
+    stretch(=, size: #2mm)^(k = 0)_(forall i) T \
+  U stretch(equiv)^(forall i)_"Chern-Weil" V
+    stretch(equiv, size: #(120% + 2mm))^(forall i)_"Chern-Weil" W $
+
+--- math-stretch-horizontal ---
+// Test stretching along horizontal axis.
+#let ext(sym) = math.stretch(sym, size: 2em)
+$ ext(arrow.r) quad ext(arrow.l.double.bar) \
+  ext(harpoon.rb) quad ext(harpoons.ltrb) \
+  ext(paren.t) quad ext(shell.b) \
+  ext(eq) quad ext(equiv) $
+
+--- math-stretch-vertical ---
+// Test stretching along vertical axis.
+#let ext(sym) = math.stretch(sym, size: 2em)
+$ ext(bar.v) quad ext(bar.v.double) quad
+  ext(angle.l) quad ext(angle.r) quad
+  ext(paren.l) quad ext(paren.r) \
+  ext(bracket.l.double) quad ext(bracket.r.double) quad
+  ext(brace.l) quad ext(brace.r) quad
+  ext(bracket.l) quad ext(bracket.r) $
+
+--- math-stretch-shorthand ---
+// Test stretch when base is given with shorthand.
+$stretch(||, size: #2em)$
+$stretch(\(, size: #2em)$
+$stretch("⟧", size: #2em)$
+$stretch("|", size: #2em)$
+$stretch(->, size: #2em)$
+$stretch(↣, size: #2em)$
+
+--- math-stretch-nested ---
+// Test nested stretch calls.
+$ stretch(=, size: #2em) \
+  stretch(stretch(=, size: #4em), size: #50%) $
+
+#let base = math.stretch($=$, size: 4em)
+$ stretch(base, size: #50%) $
+
+#let base = $stretch(=, size: #4em) $
+$ stretch(base, size: #50%) $
+
+--- math-stretch-attach-nested-equation ---
+// Test stretching with attachments when nested in an equation.
+#let body = $stretch(=)$
+$ body^"text" $