Better space coalescing logic 🌧

This creates a smaller state machine helper type for softness coalescing, which does not own the resulting nodes. While this creates a bit more duplication in stack and par builder, it makes it a lot easier to integrate additional logic into the paragraph builder.

Furthermore:
- Line breaks are now "hard", that is, not coalesced with each other.
- Text nodes with equal style are now merged allowing for example `f{}i` to form a ligature.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/layout/par.rs b/src/layout/par.rs
index 02e27cbd..e0b42821 100644
--- a/src/layout/par.rs
+++ b/src/layout/par.rs
@@ -23,6 +23,8 @@ pub enum ParChild {
     Text(TextNode, Align),
     /// Any child node and how to align it in its line.
     Any(AnyNode, Align),
+    /// A forced linebreak.
+    Linebreak,
 }
 
 /// A consecutive, styled run of text.
@@ -55,6 +57,7 @@ impl Layout for ParNode {
                         layouter.push_frame(frame, align);
                     }
                 }
+                ParChild::Linebreak => layouter.finish_line(),
             }
         }
         layouter.finish()