font: render dotted underlines

src/font/sprite.zig

@@ -16,6 +16,7 @@ pub const Sprite = enum(u32) {
 
     underline = start,
     underline_double = start + 1,
+    underline_dotted = start + 2,
 
     // Note: we don't currently put the box drawing glyphs in here because
     // there are a LOT and I'm lazy. What I want to do is spend more time

src/font/sprite/Face.zig

@@ -85,6 +85,7 @@ const Kind = enum {
             Sprite.start...Sprite.end => switch (@intToEnum(Sprite, cp)) {
                 .underline,
                 .underline_double,
+                .underline_dotted,
                 => .underline,
             },
 

src/font/sprite/underline.zig

@@ -69,6 +69,7 @@ const Draw = struct {
         switch (sprite) {
             .underline => self.drawSingle(canvas),
             .underline_double => self.drawDouble(canvas),
+            .underline_dotted => self.drawDotted(canvas),
         }
     }
 
@@ -98,6 +99,21 @@ const Draw = struct {
             .height = self.thickness,
         }, .on);
     }
+
+    /// Draw a dotted underline.
+    fn drawDotted(self: Draw, canvas: *font.sprite.Canvas) void {
+        const dot_width = @max(self.thickness, 3);
+        const dot_count = self.width / dot_width;
+        var i: u32 = 0;
+        while (i < dot_count) : (i += 2) {
+            canvas.rect(.{
+                .x = i * dot_width,
+                .y = self.pos,
+                .width = dot_width,
+                .height = self.thickness,
+            }, .on);
+        }
+    }
 };
 
 test "single" {

src/renderer/OpenGL.zig

@@ -1009,6 +1009,7 @@ pub fn updateCell(
             .none => unreachable,
             .single => .underline,
             .double => .underline_double,
+            .dotted => .underline_dotted,
             else => .underline,
         };