font: add sprites for the separated block quadrants (#2975)

Unicode 16 added "Separated Block Quadrants" from CP 0x0x1CC21 through
0x1CC2F:

𜰡 𜰢 𜰣 𜰤 𜰥 𜰦 𜰧 𜰨 𜰩 𜰪 𜰫 𜰬 𜰭 𜰮 𜰯

To test, use the following command:

```
printf "\U0001CC21\U0001CC22\U0001CC23\U0001CC24\U0001CC25\U0001CC26\U0001CC27\U0001CC28\U0001CC29\U0001CC2A\U0001CC2B\U0001CC2C\U0001CC2D\U0001CC2E\U0001CC2F\n"
```

Which should look like this:

![Screenshot From 2024-12-15
13-15-31](https://github.com/user-attachments/assets/fcf825e1-c824-4f56-8c7d-b4e126401c2b)

cc @qwerasd205 @rockorager

.gitignore

@@ -15,3 +15,5 @@ test/ghostty
 test/cases/**/*.actual.png
 
 glad.zip
+/Box_test.ppm
+/Box_test_diff.ppm

src/font/sprite/Box.zig

@@ -1624,6 +1624,37 @@ fn draw(self: Box, alloc: Allocator, canvas: *font.sprite.Canvas, cp: u32) !void
             .right = true,
         }, .light),
 
+        // '𜰡' - SEPARATED BLOCK QUADRANT-1
+        0x1cc21 => try self.draw_separated_block_quadrant(canvas, "1"),
+        // '𜰢' - SEPARATED BLOCK QUADRANT-2
+        0x1cc22 => try self.draw_separated_block_quadrant(canvas, "2"),
+        // '𜰣' - SEPARATED BLOCK QUADRANT-12
+        0x1cc23 => try self.draw_separated_block_quadrant(canvas, "12"),
+        // '𜰤' - SEPARATED BLOCK QUADRANT-3
+        0x1cc24 => try self.draw_separated_block_quadrant(canvas, "3"),
+        // '𜰥' - SEPARATED BLOCK QUADRANT-13
+        0x1cc25 => try self.draw_separated_block_quadrant(canvas, "13"),
+        // '𜰦' - SEPARATED BLOCK QUADRANT-23
+        0x1cc26 => try self.draw_separated_block_quadrant(canvas, "23"),
+        // '𜰧' - SEPARATED BLOCK QUADRANT-123
+        0x1cc27 => try self.draw_separated_block_quadrant(canvas, "123"),
+        // '𜰨' - SEPARATED BLOCK QUADRANT-4
+        0x1cc28 => try self.draw_separated_block_quadrant(canvas, "4"),
+        // '𜰩' - SEPARATED BLOCK QUADRANT-14
+        0x1cc29 => try self.draw_separated_block_quadrant(canvas, "14"),
+        // '𜰪' - SEPARATED BLOCK QUADRANT-24
+        0x1cc2a => try self.draw_separated_block_quadrant(canvas, "24"),
+        // '𜰫' - SEPARATED BLOCK QUADRANT-124
+        0x1cc2b => try self.draw_separated_block_quadrant(canvas, "124"),
+        // '𜰬' - SEPARATED BLOCK QUADRANT-34
+        0x1cc2c => try self.draw_separated_block_quadrant(canvas, "34"),
+        // '𜰭' - SEPARATED BLOCK QUADRANT-134
+        0x1cc2d => try self.draw_separated_block_quadrant(canvas, "134"),
+        // '𜰮' - SEPARATED BLOCK QUADRANT-234
+        0x1cc2e => try self.draw_separated_block_quadrant(canvas, "234"),
+        // '𜰯' - SEPARATED BLOCK QUADRANT-1234
+        0x1cc2f => try self.draw_separated_block_quadrant(canvas, "1234"),
+
         else => return error.InvalidCodepoint,
     }
 }
@@ -2865,6 +2896,74 @@ fn rect(
     } }).rect(), .on);
 }
 
+// Separated Block Quadrants from Symbols for Legacy Computing Supplement
+// 𜰡 𜰢 𜰣 𜰤 𜰥 𜰦 𜰧 𜰨 𜰩 𜰪 𜰫 𜰬 𜰭 𜰮 𜰯
+fn draw_separated_block_quadrant(self: Box, canvas: *font.sprite.Canvas, comptime fmt: []const u8) !void {
+    comptime {
+        if (fmt.len > 4) @compileError("cannot have more than four quadrants");
+        var seen = [_]bool{false} ** (std.math.maxInt(u8) + 1);
+        for (fmt) |c| {
+            if (seen[c]) @compileError("repeated quadrants not allowed");
+            seen[c] = true;
+            switch (c) {
+                '1'...'4' => {},
+                else => @compileError("invalid quadrant"),
+            }
+        }
+    }
+
+    var ctx: z2d.Context = .{
+        .surface = canvas.sfc,
+        .pattern = .{
+            .opaque_pattern = .{
+                .pixel = .{ .alpha8 = .{ .a = @intFromEnum(Shade.on) } },
+            },
+        },
+    };
+
+    const gap: f64 = @max(1.0, @as(f64, @floatFromInt(self.metrics.cell_width)) * 0.10) / 2.0;
+    const left: f64 = gap;
+    const right = @as(f64, @floatFromInt(self.metrics.cell_width)) - gap;
+    const top: f64 = gap;
+    const bottom = @as(f64, @floatFromInt(self.metrics.cell_height)) - gap;
+    const center_x = @as(f64, @floatFromInt(self.metrics.cell_width)) / 2.0;
+    const center_left = center_x - gap;
+    const center_right = center_x + gap;
+    const center_y = @as(f64, @floatFromInt(self.metrics.cell_height)) / 2.0;
+    const center_top = center_y - gap;
+    const center_bottom = center_y + gap;
+
+    inline for (fmt) |c| {
+        const x1, const y1, const x2, const y2 = switch (c) {
+            '1' => .{
+                left,        top,
+                center_left, center_top,
+            },
+            '2' => .{
+                center_right, top,
+                right,        center_top,
+            },
+            '3' => .{
+                left,        center_bottom,
+                center_left, bottom,
+            },
+            '4' => .{
+                center_right, center_bottom,
+                right,        bottom,
+            },
+            else => unreachable,
+        };
+        var path = z2d.Path.init(canvas.alloc);
+        defer path.deinit();
+        try path.moveTo(x1, y1);
+        try path.lineTo(x2, y1);
+        try path.lineTo(x2, y2);
+        try path.lineTo(x1, y2);
+        try path.close();
+        try ctx.fill(canvas.alloc, path);
+    }
+}
+
 test "all" {
     const testing = std.testing;
     const alloc = testing.allocator;
@@ -2994,6 +3093,20 @@ fn testRenderAll(self: Box, alloc: Allocator, atlas: *font.Atlas) !void {
             cp,
         );
     }
+
+    // Symbols for Legacy Computing Supplement.
+    // 𜰡 𜰢 𜰣 𜰤 𜰥 𜰦 𜰧 𜰨 𜰩 𜰪 𜰫 𜰬 𜰭 𜰮 𜰯
+    cp = 0x1cc21;
+    while (cp <= 0x1cc2f) : (cp += 1) {
+        switch (cp) {
+            0x1cc21...0x1cc2f => _ = try self.renderGlyph(
+                alloc,
+                atlas,
+                cp,
+            ),
+            else => {},
+        }
+    }
 }
 
 test "render all sprites" {

src/font/sprite/Face.zig

@@ -152,7 +152,6 @@ pub fn renderGlyph(
 
             break :cursor g;
         },
-
     };
 }
 
@@ -263,6 +262,10 @@ const Kind = enum {
             //            
             0xF5D0...0xF60D => .box,
 
+            // Separated Block Quadrants from Symbols for Legacy Computing Supplement
+            // 𜰡 𜰢 𜰣 𜰤 𜰥 𜰦 𜰧 𜰨 𜰩 𜰪 𜰫 𜰬 𜰭 𜰮 𜰯
+            0x1CC21...0x1CC2F => .box,
+
             // Powerline fonts
             0xE0B0,
             0xE0B1,