feat: Allow setting the primary level for a group

Author: Muscraft

examples/elide_header.rs

@@ -9,6 +9,7 @@ def foobar(foor, bar={}):
 "#;
 
     let message = &[Group::new()
+        .primary_level(Level::NOTE)
         .element(
             Snippet::source(source)
                 .fold(false)

examples/elide_header.svg

@@ -275,14 +275,16 @@ impl Renderer {
                 if og_primary_path.is_none() && primary_path.is_some() {
                     og_primary_path = primary_path;
                 }
-                let level = group
-                    .elements
-                    .iter()
-                    .find_map(|s| match &s {
-                        Element::Title(title) => Some(title.level.clone()),
-                        _ => None,
-                    })
-                    .unwrap_or(Level::ERROR);
+                let level = group.primary_level.clone().unwrap_or_else(|| {
+                    group
+                        .elements
+                        .first()
+                        .and_then(|s| match &s {
+                            Element::Title(title) => Some(title.level.clone()),
+                            _ => None,
+                        })
+                        .unwrap_or(Level::ERROR)
+                });
                 let mut source_map_annotated_lines = VecDeque::new();
                 let mut max_depth = 0;
                 for e in &group.elements {

src/renderer/mod.rs

@@ -20,6 +20,7 @@ pub(crate) struct Id<'a> {
 /// An [`Element`] container
 #[derive(Clone, Debug)]
 pub struct Group<'a> {
+    pub(crate) primary_level: Option<Level<'a>>,
     pub(crate) elements: Vec<Element<'a>>,
 }
 
@@ -31,7 +32,10 @@ impl Default for Group<'_> {
 
 impl<'a> Group<'a> {
     pub fn new() -> Self {
-        Self { elements: vec![] }
+        Self {
+            primary_level: None,
+            elements: vec![],
+        }
     }
 
     pub fn element(mut self, section: impl Into<Element<'a>>) -> Self {
@@ -44,6 +48,14 @@ impl<'a> Group<'a> {
         self
     }
 
+    /// Set the primary [`Level`] for this [`Group`]. If not specified, the
+    /// [`Level`] of the first [`Title`] in the [`Group`] will be used, if no
+    /// [`Title`] is present, it will default to [`Level::ERROR`].
+    pub fn primary_level(mut self, level: Level<'a>) -> Self {
+        self.primary_level = Some(level);
+        self
+    }
+
     pub fn is_empty(&self) -> bool {
         self.elements.is_empty()
     }