Support different kinds of underline rendering

Adds four new  modifiers that can be used in themes:

- undercurled
- underdashed
- underdotted
- double-underline

1 files changed, 13 insertions, 1 deletions

diff --git a/helix-tui/src/backend/crossterm.rs b/helix-tui/src/backend/crossterm.rs
index eff098b3..252036f3 100644
--- a/helix-tui/src/backend/crossterm.rs
+++ b/helix-tui/src/backend/crossterm.rs
@@ -153,7 +153,7 @@ impl ModifierDiff {
         if removed.contains(Modifier::ITALIC) {
             map_error(queue!(w, SetAttribute(CAttribute::NoItalic)))?;
         }
-        if removed.contains(Modifier::UNDERLINED) {
+        if removed.intersects(Modifier::ANY_UNDERLINE) {
             map_error(queue!(w, SetAttribute(CAttribute::NoUnderline)))?;
         }
         if removed.contains(Modifier::DIM) {
@@ -179,6 +179,18 @@ impl ModifierDiff {
         if added.contains(Modifier::UNDERLINED) {
             map_error(queue!(w, SetAttribute(CAttribute::Underlined)))?;
         }
+        if added.contains(Modifier::UNDERCURLED) {
+            map_error(queue!(w, SetAttribute(CAttribute::Undercurled)))?;
+        }
+        if added.contains(Modifier::UNDERDOTTED) {
+            map_error(queue!(w, SetAttribute(CAttribute::Underdotted)))?;
+        }
+        if added.contains(Modifier::UNDERDASHED) {
+            map_error(queue!(w, SetAttribute(CAttribute::Underdashed)))?;
+        }
+        if added.contains(Modifier::DOUBLE_UNDERLINED) {
+            map_error(queue!(w, SetAttribute(CAttribute::DoubleUnderlined)))?;
+        }
         if added.contains(Modifier::DIM) {
             map_error(queue!(w, SetAttribute(CAttribute::Dim)))?;
         }