font: turn rasterization options into a struct, add thicken

src/config.zig

@@ -34,6 +34,10 @@ pub const Config = struct {
         else => 12,
     },
 
+    /// Draw fonts with a thicker stroke, if supported. This is only supported
+    /// currently on macOS.
+    @"font-thicken": bool = false,
+
     /// Background color for the window.
     background: Color = .{ .r = 0x28, .g = 0x2C, .b = 0x34 },
 

src/font/Group.zig

@@ -269,7 +269,7 @@ pub fn renderGlyph(
     atlas: *font.Atlas,
     index: FontIndex,
     glyph_index: u32,
-    max_height: ?u16,
+    opts: font.face.RenderOptions,
 ) !Glyph {
     // Special-case fonts are rendered directly.
     if (index.special()) |sp| switch (sp) {
@@ -282,7 +282,7 @@ pub fn renderGlyph(
 
     const face = &self.faces.get(index.style).items[@intCast(index.idx)];
     try face.load(self.lib, self.size);
-    const glyph = try face.face.?.renderGlyph(alloc, atlas, glyph_index, max_height);
+    const glyph = try face.face.?.renderGlyph(alloc, atlas, glyph_index, opts);
     // log.warn("GLYPH={}", .{glyph});
     return glyph;
 }
@@ -383,7 +383,9 @@ pub const Wasm = struct {
     ) !*Glyph {
         const idx = @as(FontIndex, @bitCast(@as(u8, @intCast(idx_))));
         const max_height = if (max_height_ <= 0) null else max_height_;
-        const glyph = try self.renderGlyph(alloc, atlas, idx, cp, max_height);
+        const glyph = try self.renderGlyph(alloc, atlas, idx, cp, .{
+            .max_height = max_height,
+        });
 
         var result = try alloc.create(Glyph);
         errdefer alloc.destroy(result);
@@ -427,7 +429,7 @@ test {
             &atlas_greyscale,
             idx,
             glyph_index,
-            null,
+            .{},
         );
     }
 
@@ -483,7 +485,7 @@ test "box glyph" {
         &atlas_greyscale,
         idx,
         0x2500,
-        null,
+        .{},
     );
     try testing.expectEqual(@as(u32, 36), glyph.height);
 }
@@ -514,7 +516,7 @@ test "resize" {
             &atlas_greyscale,
             idx,
             glyph_index,
-            null,
+            .{},
         );
 
         try testing.expectEqual(@as(u32, 11), glyph.height);
@@ -531,7 +533,7 @@ test "resize" {
             &atlas_greyscale,
             idx,
             glyph_index,
-            null,
+            .{},
         );
 
         try testing.expectEqual(@as(u32, 21), glyph.height);
@@ -574,7 +576,7 @@ test "discover monospace with fontconfig and freetype" {
             &atlas_greyscale,
             idx,
             glyph_index,
-            null,
+            .{},
         );
     }
 }

src/font/GroupCache.zig

@@ -122,7 +122,7 @@ pub fn renderGlyph(
     alloc: Allocator,
     index: Group.FontIndex,
     glyph_index: u32,
-    max_height: ?u16,
+    opts: font.face.RenderOptions,
 ) !Glyph {
     const key: GlyphKey = .{ .index = index, .glyph = glyph_index };
     const gop = try self.glyphs.getOrPut(alloc, key);
@@ -140,7 +140,7 @@ pub fn renderGlyph(
         atlas,
         index,
         glyph_index,
-        max_height,
+        opts,
     ) catch |err| switch (err) {
         // If the atlas is full, we resize it
         error.AtlasFull => blk: {
@@ -150,7 +150,7 @@ pub fn renderGlyph(
                 atlas,
                 index,
                 glyph_index,
-                max_height,
+                opts,
             );
         },
 
@@ -203,7 +203,7 @@ test {
             alloc,
             idx,
             glyph_index,
-            null,
+            .{},
         );
     }
 
@@ -225,7 +225,7 @@ test {
                 alloc,
                 idx,
                 glyph_index,
-                null,
+                .{},
             );
         }
     }
@@ -300,7 +300,9 @@ pub const Wasm = struct {
     ) !*Glyph {
         const idx = @as(Group.FontIndex, @bitCast(@as(u8, @intCast(idx_))));
         const max_height = if (max_height_ <= 0) null else max_height_;
-        const glyph = try self.renderGlyph(alloc, idx, cp, max_height);
+        const glyph = try self.renderGlyph(alloc, idx, cp, .{
+            .max_height = max_height,
+        });
 
         var result = try alloc.create(Glyph);
         errdefer alloc.destroy(result);
@@ -352,7 +354,7 @@ test "resize" {
             alloc,
             idx,
             glyph_index,
-            null,
+            .{},
         );
 
         try testing.expectEqual(@as(u32, 11), glyph.height);
@@ -368,7 +370,7 @@ test "resize" {
             alloc,
             idx,
             glyph_index,
-            null,
+            .{},
         );
 
         try testing.expectEqual(@as(u32, 21), glyph.height);

src/font/face.zig

@@ -58,6 +58,20 @@ pub const Metrics = struct {
     strikethrough_thickness: f32,
 };
 
+/// Additional options for rendering glyphs.
+pub const RenderOptions = struct {
+    /// The maximum height of the glyph. If this is set, then any glyph
+    /// larger than this height will be shrunk to this height. The scaling
+    /// is typically naive, but ultimately up to the rasterizer.
+    max_height: ?u16 = null,
+
+    /// Thicken the glyph. This draws the glyph with a thicker stroke width.
+    /// This is purely an aesthetic setting.
+    ///
+    /// This only works with CoreText currently.
+    thicken: bool = false,
+};
+
 pub const Foo = if (options.backend == .coretext) coretext.Face else void;
 
 test {

src/font/face/coretext.zig

@@ -102,10 +102,8 @@ pub const Face = struct {
         alloc: Allocator,
         atlas: *font.Atlas,
         glyph_index: u32,
-        max_height: ?u16,
+        opts: font.face.RenderOptions,
     ) !font.Glyph {
-        _ = max_height;
-
         var glyphs = [_]macos.graphics.Glyph{@intCast(glyph_index)};
 
         // Get the bounding rect for rendering this glyph.
@@ -205,7 +203,7 @@ pub const Face = struct {
         });
 
         ctx.setAllowsFontSmoothing(true);
-        ctx.setShouldSmoothFonts(false); // The amadeus "enthicken"
+        ctx.setShouldSmoothFonts(opts.thicken); // The amadeus "enthicken"
         ctx.setAllowsFontSubpixelQuantization(true);
         ctx.setShouldSubpixelQuantizeFonts(true);
         ctx.setAllowsFontSubpixelPositioning(true);
@@ -479,7 +477,7 @@ test {
     var i: u8 = 32;
     while (i < 127) : (i += 1) {
         try testing.expect(face.glyphIndex(i) != null);
-        _ = try face.renderGlyph(alloc, &atlas, face.glyphIndex(i).?, null);
+        _ = try face.renderGlyph(alloc, &atlas, face.glyphIndex(i).?, .{});
     }
 }
 
@@ -523,6 +521,6 @@ test "in-memory" {
     var i: u8 = 32;
     while (i < 127) : (i += 1) {
         try testing.expect(face.glyphIndex(i) != null);
-        _ = try face.renderGlyph(alloc, &atlas, face.glyphIndex(i).?, null);
+        _ = try face.renderGlyph(alloc, &atlas, face.glyphIndex(i).?, .{});
     }
 }

src/font/face/freetype.zig

@@ -124,7 +124,7 @@ pub const Face = struct {
         alloc: Allocator,
         atlas: *font.Atlas,
         glyph_index: u32,
-        max_height: ?u16,
+        opts: font.face.RenderOptions,
     ) !Glyph {
         // If our glyph has color, we want to render the color
         try self.face.loadGlyph(glyph_index, .{
@@ -188,7 +188,7 @@ pub const Face = struct {
         // and copy the atlas.
         const bitmap_original = bitmap_converted orelse bitmap_ft;
         const bitmap_resized: ?freetype.c.struct_FT_Bitmap_ = resized: {
-            const max = max_height orelse break :resized null;
+            const max = opts.max_height orelse break :resized null;
             const bm = bitmap_original;
             if (bm.rows <= max) break :resized null;
 
@@ -522,16 +522,16 @@ test {
     // Generate all visible ASCII
     var i: u8 = 32;
     while (i < 127) : (i += 1) {
-        _ = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex(i).?, null);
+        _ = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex(i).?, .{});
     }
 
     // Test resizing
     {
-        const g1 = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('A').?, null);
+        const g1 = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('A').?, .{});
         try testing.expectEqual(@as(u32, 11), g1.height);
 
         try ft_font.setSize(.{ .points = 24, .xdpi = 96, .ydpi = 96 });
-        const g2 = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('A').?, null);
+        const g2 = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('A').?, .{});
         try testing.expectEqual(@as(u32, 21), g2.height);
     }
 }
@@ -551,11 +551,13 @@ test "color emoji" {
 
     try testing.expectEqual(Presentation.emoji, ft_font.presentation);
 
-    _ = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('🥸').?, null);
+    _ = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('🥸').?, .{});
 
     // resize
     {
-        const glyph = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('🥸').?, 24);
+        const glyph = try ft_font.renderGlyph(alloc, &atlas, ft_font.glyphIndex('🥸').?, .{
+            .max_height = 24,
+        });
         try testing.expectEqual(@as(u32, 24), glyph.height);
     }
 }
@@ -610,5 +612,5 @@ test "mono to rgba" {
     defer ft_font.deinit();
 
     // glyph 3 is mono in Noto
-    _ = try ft_font.renderGlyph(alloc, &atlas, 3, null);
+    _ = try ft_font.renderGlyph(alloc, &atlas, 3, .{});
 }

src/font/face/web_canvas.zig

@@ -190,9 +190,9 @@ pub const Face = struct {
         alloc: Allocator,
         atlas: *font.Atlas,
         glyph_index: u32,
-        max_height: ?u16,
+        opts: font.face.RenderOptions,
     ) !font.Glyph {
-        _ = max_height;
+        _ = opts;
 
         var render = try self.renderGlyphInternal(alloc, glyph_index);
         defer render.deinit();
@@ -551,7 +551,7 @@ pub const Wasm = struct {
     }
 
     fn face_render_glyph_(face: *Face, atlas: *font.Atlas, codepoint: u32) !*font.Glyph {
-        const glyph = try face.renderGlyph(alloc, atlas, codepoint, null);
+        const glyph = try face.renderGlyph(alloc, atlas, codepoint, .{});
 
         const result = try alloc.create(font.Glyph);
         errdefer alloc.destroy(result);

src/renderer/Metal.zig

@@ -996,7 +996,9 @@ pub fn updateCell(
             self.alloc,
             shaper_run.font_index,
             shaper_cell.glyph_index,
-            @intFromFloat(@ceil(self.cell_size.height)),
+            .{
+                .max_height = @intFromFloat(@ceil(self.cell_size.height)),
+            },
         );
 
         // If we're rendering a color font, we use the color atlas
@@ -1031,7 +1033,7 @@ pub fn updateCell(
             self.alloc,
             font.sprite_index,
             @intFromEnum(sprite),
-            null,
+            .{},
         );
 
         const color = if (cell.attrs.underline_color) cell.underline_fg else colors.fg;
@@ -1083,7 +1085,7 @@ fn addCursor(self: *Metal, screen: *terminal.Screen) void {
         self.alloc,
         font.sprite_index,
         @intFromEnum(sprite),
-        null,
+        .{},
     ) catch |err| {
         log.warn("error rendering cursor glyph err={}", .{err});
         return;

src/renderer/OpenGL.zig

@@ -991,7 +991,7 @@ fn addCursor(self: *OpenGL, screen: *terminal.Screen) void {
         self.alloc,
         font.sprite_index,
         @intFromEnum(sprite),
-        null,
+        .{},
     ) catch |err| {
         log.warn("error rendering cursor glyph err={}", .{err});
         return;
@@ -1144,7 +1144,7 @@ pub fn updateCell(
             self.alloc,
             shaper_run.font_index,
             shaper_cell.glyph_index,
-            @intFromFloat(@ceil(self.cell_size.height)),
+            .{ .max_height = @intFromFloat(@ceil(self.cell_size.height)) },
         );
 
         // If we're rendering a color font, we use the color atlas
@@ -1190,7 +1190,7 @@ pub fn updateCell(
             self.alloc,
             font.sprite_index,
             @intFromEnum(sprite),
-            null,
+            .{},
         );
 
         const color = if (cell.attrs.underline_color) cell.underline_fg else colors.fg;