Add support for Beam, Underline cursors

Notable about this implementation is it takes a different approach for
managing cursor cells that previously. The terminal Grid is now
borrowed *immutably*. Instead of mutating Cells in the Grid, a list is
managed within the RenderableCellsIter. The cell at the cursor location
is skipped over, and instead cells are popped off a list of cursor
cells.

It would be good in the future to share some more code between the
different cursor style implementations for populating the cursor cells
list.

Supercedes #349.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/term/cell.rs b/src/term/cell.rs
index cb966156..98d46bf2 100644
--- a/src/term/cell.rs
+++ b/src/term/cell.rs
@@ -86,6 +86,17 @@ impl Cell {
         }
     }
 
+    /// Get foreground and background colors adjusted for INVERSE flag
+    ///
+    /// First color is the foreground, second color is the background.
+    pub fn colors(&self, force_invert: bool) -> (&Color, &Color) {
+        if self.flags.contains(INVERSE) || force_invert {
+            (&self.bg, &self.fg)
+        } else {
+            (&self.fg, &self.bg)
+        }
+    }
+
     #[inline]
     pub fn is_empty(&self) -> bool {
         self.c == ' ' &&