Add fields and methods to several primitives (#790)

2 files changed, 22 insertions, 0 deletions

diff --git a/crates/typst-library/src/layout/align.rs b/crates/typst-library/src/layout/align.rs
index bbfe9f7e..fecc7e33 100644
--- a/crates/typst-library/src/layout/align.rs
+++ b/crates/typst-library/src/layout/align.rs
@@ -33,10 +33,23 @@ pub struct AlignElem {
     /// - `horizon`
     /// - `bottom`
     ///
+    /// You may use the `axis` method on a single-axis alignment to obtain
+    /// whether it is `{"horizontal"}` or `{"vertical"}`. You may also use the
+    /// `inv` method to obtain its inverse alignment. For example,
+    /// `{top.axis()}` is `{"vertical"}`, while `{top.inv()}` is equal to
+    /// `{bottom}`.
+    ///
     /// To align along both axes at the same time, add the two alignments using
     /// the `+` operator to get a `2d alignment`. For example, `top + right`
     /// aligns the content to the top right corner.
     ///
+    /// For 2d alignments, you may use the `x` and `y` fields to access their
+    /// horizontal and vertical components, respectively. Additionally, you may
+    /// use the `inv` method to obtain a 2d alignment with both components
+    /// inverted. For instance, `{(top + right).x}` is `right`,
+    /// `{(top + right).y}` is `top`, and `{(top + right).inv()}` is equal to
+    /// `bottom + left`.
+    ///
     /// ```example
     /// #set page(height: 6cm)
     /// #set text(lang: "ar")
diff --git a/crates/typst-library/src/layout/stack.rs b/crates/typst-library/src/layout/stack.rs
index 97305ddf..8d536638 100644
--- a/crates/typst-library/src/layout/stack.rs
+++ b/crates/typst-library/src/layout/stack.rs
@@ -26,6 +26,15 @@ pub struct StackElem {
     /// - `{rtl}`: Right to left.
     /// - `{ttb}`: Top to bottom.
     /// - `{btt}`: Bottom to top.
+    ///
+    /// You may use the `start` and `end` methods to obtain the initial and
+    /// final points (respectively) of a direction, as `alignment`. You may
+    /// also use the `axis` method to obtain whether a direction is
+    /// `{"horizontal"}` or `{"vertical"}`. Finally, the `inv` method returns
+    /// its inverse direction.
+    ///
+    /// For example, `{ttb.start()}` is `top`, `{ttb.end()}` is `bottom`,
+    /// `{ttb.axis()}` is `{"vertical"}` and `{ttb.inv()}` is equal to `btt`.
     #[default(Dir::TTB)]
     pub dir: Dir,