config: add remaining font modifiers

src/Surface.zig

@@ -231,6 +231,10 @@ pub fn init(
             if (config.@"adjust-cell-width") |m| try set.put(alloc, .cell_width, m);
             if (config.@"adjust-cell-height") |m| try set.put(alloc, .cell_height, m);
             if (config.@"adjust-font-baseline") |m| try set.put(alloc, .cell_baseline, m);
+            if (config.@"adjust-underline-position") |m| try set.put(alloc, .underline_position, m);
+            if (config.@"adjust-underline-thickness") |m| try set.put(alloc, .underline_thickness, m);
+            if (config.@"adjust-strikethrough-position") |m| try set.put(alloc, .strikethrough_position, m);
+            if (config.@"adjust-strikethrough-thickness") |m| try set.put(alloc, .strikethrough_thickness, m);
             break :set set;
         };
 

src/config/Config.zig

@@ -138,6 +138,10 @@ const c = @cImport({
 @"adjust-cell-width": ?MetricModifier = null,
 @"adjust-cell-height": ?MetricModifier = null,
 @"adjust-font-baseline": ?MetricModifier = null,
+@"adjust-underline-position": ?MetricModifier = null,
+@"adjust-underline-thickness": ?MetricModifier = null,
+@"adjust-strikethrough-position": ?MetricModifier = null,
+@"adjust-strikethrough-thickness": ?MetricModifier = null,
 
 /// Background color for the window.
 background: Color = .{ .r = 0x28, .g = 0x2C, .b = 0x34 },

src/font/face/Metrics.zig

@@ -26,6 +26,18 @@ pub fn apply(self: *Metrics, mods: ModifierSet) void {
     var it = mods.iterator();
     while (it.next()) |entry| {
         switch (entry.key_ptr.*) {
+            // We clamp these values to a minimum of 1 to prevent divide-by-zero
+            // in downstream operations.
+            inline .cell_width,
+            .cell_height,
+            => |tag| {
+                const original = @field(self, @tagName(tag));
+                @field(self, @tagName(tag)) = @max(
+                    entry.value_ptr.apply(original),
+                    1,
+                );
+            },
+
             inline else => |tag| {
                 @field(self, @tagName(tag)) = entry.value_ptr.apply(@field(self, @tagName(tag)));
             },

src/font/sprite/underline.zig

@@ -171,8 +171,9 @@ const Draw = struct {
         // wave. This constant is arbitrary, change it for aesthetics.
         const pos = pos: {
             const MIN_HEIGHT = 7;
-            const height = y_max - self.pos;
+            const clamped_pos = @min(y_max, self.pos);
-            break :pos if (height < MIN_HEIGHT) self.pos -| MIN_HEIGHT else self.pos;
+            const height = y_max - clamped_pos;
+            break :pos if (height < MIN_HEIGHT) clamped_pos -| MIN_HEIGHT else clamped_pos;
         };
 
         // The full heightof the wave can be from the bottom to the

src/renderer/Metal.zig

@@ -211,7 +211,8 @@ pub fn init(alloc: Allocator, options: renderer.Options) !Metal {
     options.font_group.group.sprite = font.sprite.Face{
         .width = metrics.cell_width,
         .height = metrics.cell_height,
-        .thickness = 2 * @as(u32, if (options.config.font_thicken) 2 else 1),
+        .thickness = metrics.underline_thickness *
+            @as(u32, if (options.config.font_thicken) 2 else 1),
         .underline_position = metrics.underline_position,
     };
 

src/renderer/OpenGL.zig

@@ -548,7 +548,7 @@ fn resetFontMetrics(
     font_group.group.sprite = font.sprite.Face{
         .width = metrics.cell_width,
         .height = metrics.cell_height,
-        .thickness = 2 * @as(u32, if (font_thicken) 2 else 1),
+        .thickness = metrics.underline_thickness * @as(u32, if (font_thicken) 2 else 1),
         .underline_position = metrics.underline_position,
     };