Basic HTML pretty-printing (#5533)

Co-authored-by: Laurenz <laurmaedje@gmail.com>

1 files changed, 54 insertions, 1 deletions

diff --git a/crates/typst-library/src/html/dom.rs b/crates/typst-library/src/html/dom.rs
index ee94279f..3d558fb0 100644
--- a/crates/typst-library/src/html/dom.rs
+++ b/crates/typst-library/src/html/dom.rs
@@ -470,6 +470,59 @@ pub mod tag {
         wbr
     }
 
+    /// Whether nodes with the tag have the CSS property `display: block` by
+    /// default.
+    ///
+    /// If this is true, then pretty-printing can insert spaces around such
+    /// nodes and around the contents of such nodes.
+    ///
+    /// However, when users change the properties of such tags via CSS, the
+    /// insertion of whitespace may actually impact the visual output; for
+    /// example, <https://www.w3.org/TR/css-text-3/#example-af2745cd> shows how
+    /// adding CSS rules to `<p>` can make it sensitive to whitespace. In such
+    /// cases, users should disable pretty-printing.
+    pub fn is_block_by_default(tag: HtmlTag) -> bool {
+        matches!(
+            tag,
+            self::html
+                | self::head
+                | self::body
+                | self::article
+                | self::aside
+                | self::h1
+                | self::h2
+                | self::h3
+                | self::h4
+                | self::h5
+                | self::h6
+                | self::hgroup
+                | self::nav
+                | self::section
+                | self::dd
+                | self::dl
+                | self::dt
+                | self::menu
+                | self::ol
+                | self::ul
+                | self::address
+                | self::blockquote
+                | self::dialog
+                | self::div
+                | self::fieldset
+                | self::figure
+                | self::figcaption
+                | self::footer
+                | self::form
+                | self::header
+                | self::hr
+                | self::legend
+                | self::main
+                | self::p
+                | self::pre
+                | self::search
+        )
+    }
+
     /// Whether the element is inline-level as opposed to being block-level.
     ///
     /// Not sure whether this distinction really makes sense. But we somehow
@@ -480,7 +533,7 @@ pub mod tag {
     /// <https://www.w3.org/TR/html401/struct/global.html#block-inline>
     /// <https://developer.mozilla.org/en-US/docs/Glossary/Inline-level_content>
     /// <https://github.com/orgs/mdn/discussions/353>
-    pub fn is_inline(tag: HtmlTag) -> bool {
+    pub fn is_inline_by_default(tag: HtmlTag) -> bool {
         matches!(
             tag,
             self::abbr