Added a dotted underline feature and changed the undercurl feature to be

more antialiased.

5 files changed, 124 insertions, 14 deletions

diff --git a/alacritty/src/display/content.rs b/alacritty/src/display/content.rs
index e5ff3780..6fef9574 100644
--- a/alacritty/src/display/content.rs
+++ b/alacritty/src/display/content.rs
@@ -278,7 +278,13 @@ impl RenderableCell {
         self.bg_alpha == 0.
             && self.character == ' '
             && self.zerowidth.is_none()
-            && !self.flags.intersects(Flags::UNDERLINE | Flags::STRIKEOUT | Flags::DOUBLE_UNDERLINE | Flags::UNDERCURL | Flags::OVERLINE)
+            && !self.flags.intersects(
+                Flags::UNDERLINE |
+                Flags::STRIKEOUT |
+                Flags::DOUBLE_UNDERLINE |
+                Flags::UNDERCURL |
+                Flags::OVERLINE |
+                Flags::DOTTED_UNDERLINE)
     }
 
     /// Apply [`CellRgb`] colors to the cell's colors.
diff --git a/alacritty/src/renderer/rects.rs b/alacritty/src/renderer/rects.rs
index 61ff91b7..25ae93d6 100644
--- a/alacritty/src/renderer/rects.rs
+++ b/alacritty/src/renderer/rects.rs
@@ -63,6 +63,17 @@ impl RenderLine {
         color: Rgb,
     ) {
         match flag {
+            Flags::UNDERCURL => {
+                Self::push_undercurl_rects(
+                    rects,
+                    size,
+                    metrics.descent,
+                    start,
+                    end,
+                    metrics.underline_position + 1.,
+                    metrics.underline_thickness,
+                    color)
+            }
             Flags::DOUBLE_UNDERLINE => {
                 // Position underlines so each one has 50% of descent available.
                 let top_pos = 0.25 * metrics.descent;
@@ -94,7 +105,7 @@ impl RenderLine {
                     metrics.descent,
                     start,
                     end,
-                    metrics.underline_position,
+                    metrics.underline_position + 1.,
                     metrics.underline_thickness,
                     color,
                 ));
@@ -104,7 +115,7 @@ impl RenderLine {
                 let end_x = (end.column.0 + 1) as f32 * size.cell_width();
                 rects.push(RenderRect::new(
                     start_x + size.padding_x(),
-                    start.line as f32 * size.cell_height(),
+                    (start.line as f32 * size.cell_height()) + (size.cell_height() / 8.),
                     end_x - start_x,
                     metrics.underline_thickness,
                     color,
@@ -122,14 +133,14 @@ impl RenderLine {
                     color,
                 ));
             },
-            Flags::UNDERCURL => {
-                Self::push_undercurl_rects(
+            Flags::DOTTED_UNDERLINE => {
+                Self::push_dotted_underline_rects(
                     rects,
                     size,
                     metrics.descent,
                     start,
                     end,
-                    metrics.underline_position,
+                    metrics.underline_position + 1.,
                     metrics.underline_thickness,
                     color)
             }
@@ -162,20 +173,94 @@ impl RenderLine {
             y = max_y;
         }
 
+        let period_div = 1.5 * (2. * std::f32::consts::PI) / size.cell_width();
+        let amplitude_mul = size.cell_height() / 10.;
+
         let mut x = start_x;
         let mut idx = 0;
         while x < end_x {
             let altr = [1., 0., -1., 0.][idx % 4];
 
-            let rect = RenderRect::new(
+            let fl = (x * period_div).sin() * amplitude_mul;
+            let al = (fl.round() - fl).abs();
+
+            rects.push(RenderRect::new(
                 x + size.padding_x(),
-                y + size.padding_y() + altr,
+                y + size.padding_y() + fl,
                 1.,
-                thickness + 1.,
+                thickness,
                 color,
+                (1. - al).powf(2.),
+            ));
+
+            let fl = (x * period_div).sin() * amplitude_mul - 0.5;
+            let al = (fl.round() - fl).abs();
+
+            rects.push(RenderRect::new(
+                x + size.padding_x(),
+                y + size.padding_y() + fl,
                 1.,
-            );
-            rects.push(rect);
+                thickness,
+                color,
+                (1. - al).powf(2.),
+            ));
+
+            let fl = (x * period_div).sin() * amplitude_mul + 0.5;
+            let al = (fl.round() - fl).abs();
+
+            rects.push(RenderRect::new(
+                x + size.padding_x(),
+                y + size.padding_y() + fl,
+                1.,
+                thickness,
+                color,
+                (1. - al).powf(2.),
+            ));
+
+            x += 1.;
+            idx += 1;
+        }
+    }
+
+    fn push_dotted_underline_rects(
+        rects: &mut Vec<RenderRect>,
+        size: &SizeInfo,
+        descent: f32,
+        start: Point<usize>,
+        end: Point<usize>,
+        position: f32,
+        mut thickness: f32,
+        color: Rgb,
+    ) {
+        let start_x = start.column.0 as f32 * size.cell_width();
+        let end_x = (end.column.0 + 1) as f32 * size.cell_width();
+
+        // Make sure lines are always visible.
+        thickness = thickness.max(1.);
+
+        let line_bottom = (start.line as f32 + 1.) * size.cell_height();
+        let baseline = line_bottom + descent;
+
+        let mut y = (baseline - position - thickness / 2.).ceil();
+        let max_y = line_bottom - thickness;
+        if y > max_y {
+            y = max_y;
+        }
+
+        let mut x = start_x;
+        let mut idx = 0;
+        while x < end_x {
+            if idx % 4 == 0 {
+              let rect = RenderRect::new(
+                  x + size.padding_x(),
+                  y + size.padding_y(),
+                  thickness + 1.,
+                  thickness + 1.,
+                  color,
+                  1.,
+              );
+              rects.push(rect);
+            }
             x += 1.;
             idx += 1;
         }
@@ -248,6 +333,7 @@ impl RenderLines {
         self.update_flag(cell, Flags::STRIKEOUT);
         self.update_flag(cell, Flags::UNDERCURL);
         self.update_flag(cell, Flags::OVERLINE);
+        self.update_flag(cell, Flags::DOTTED_UNDERLINE);
     }
 
     /// Update the lines for a specific flag.
diff --git a/alacritty_terminal/src/ansi.rs b/alacritty_terminal/src/ansi.rs
index 51a3394e..d5574f59 100644
--- a/alacritty_terminal/src/ansi.rs
+++ b/alacritty_terminal/src/ansi.rs
@@ -768,8 +768,10 @@ pub enum Attr {
     Underline,
     /// Underlined twice.
     DoubleUnderline,
-    /// Underlined twice.
+    /// Undercurl twice.
     Undercurl,
+    /// Underlined with dots.
+    DottedUnderline,
     /// Blink cursor slowly.
     BlinkSlow,
     /// Blink cursor fast.
@@ -971,6 +973,7 @@ where
                         .trim()
                         .to_owned();
                     self.handler.set_title(Some(title));
+                    
                     return;
                 }
                 unhandled(params);
@@ -1325,6 +1328,7 @@ fn attrs_from_sgr_parameters(params: &mut ParamsIter<'_>) -> Vec<Option<Attr>> {
             [4, 0] => Some(Attr::CancelUnderline),
             [4, 2] => Some(Attr::DoubleUnderline),
             [4, 3] => Some(Attr::Undercurl),
+            [4, 4] => Some(Attr::DottedUnderline),
             [4, ..] => Some(Attr::Underline),
             [5] => Some(Attr::BlinkSlow),
             [6] => Some(Attr::BlinkFast),
diff --git a/alacritty_terminal/src/term/cell.rs b/alacritty_terminal/src/term/cell.rs
index 4f5ac1e2..a393b332 100644
--- a/alacritty_terminal/src/term/cell.rs
+++ b/alacritty_terminal/src/term/cell.rs
@@ -25,7 +25,8 @@ bitflags! {
         const LEADING_WIDE_CHAR_SPACER  = 0b0000_0100_0000_0000;
         const DOUBLE_UNDERLINE          = 0b0000_1000_0000_0000;
         const UNDERCURL                 = 0b0001_0000_0000_0000;
-        const OVERLINE                  = 0b0010_0000_0000_0000;
+        const DOTTED_UNDERLINE          = 0b0010_0000_0000_0000;
+        const OVERLINE                  = 0b0100_0000_0000_0000;
     }
 }
 
@@ -125,6 +126,7 @@ impl GridCell for Cell {
                     | Flags::UNDERLINE
                     | Flags::DOUBLE_UNDERLINE
                     | Flags::UNDERCURL
+                    | Flags::DOTTED_UNDERLINE
                     | Flags::OVERLINE
                     | Flags::STRIKEOUT
                     | Flags::WRAPLINE
diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index 5a641a7b..ba170e32 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -1514,21 +1514,33 @@ impl<T: EventListener> Handler for Term<T> {
             Attr::Underline => {
                 cursor.template.flags.remove(Flags::DOUBLE_UNDERLINE);
                 cursor.template.flags.remove(Flags::UNDERCURL);
+                cursor.template.flags.remove(Flags::DOTTED_UNDERLINE);
                 cursor.template.flags.insert(Flags::UNDERLINE);
             },
             Attr::DoubleUnderline => {
                 cursor.template.flags.remove(Flags::UNDERLINE);
                 cursor.template.flags.remove(Flags::UNDERCURL);
+                cursor.template.flags.remove(Flags::DOTTED_UNDERLINE);
                 cursor.template.flags.insert(Flags::DOUBLE_UNDERLINE);
             },
             Attr::Undercurl => {
                 cursor.template.flags.remove(Flags::UNDERLINE);
                 cursor.template.flags.remove(Flags::DOUBLE_UNDERLINE);
+                cursor.template.flags.remove(Flags::DOTTED_UNDERLINE);
                 cursor.template.flags.insert(Flags::UNDERCURL);
             },
+            Attr::DottedUnderline => {
+                cursor.template.flags.remove(Flags::UNDERLINE);
+                cursor.template.flags.remove(Flags::DOUBLE_UNDERLINE);
+                cursor.template.flags.remove(Flags::UNDERCURL);
+                cursor.template.flags.insert(Flags::DOTTED_UNDERLINE);
+            },
             Attr::CancelUnderline => {
                 cursor.template.flags.remove(
-                    Flags::UNDERLINE | Flags::DOUBLE_UNDERLINE | Flags::UNDERCURL);
+                    Flags::UNDERLINE |
+                    Flags::DOUBLE_UNDERLINE |
+                    Flags::UNDERCURL |
+                    Flags::DOTTED_UNDERLINE);
             },
             Attr::Overline => {
                 cursor.template.flags.insert(Flags::OVERLINE);