Fix GDI zero-ink glyph handling

engine/Age.Engine.Tests/DebugSceneLaunchTests.cs

@@ -7,6 +7,36 @@ using Xunit;
 
 public class DebugSceneLaunchTests
 {
+    private sealed class ReachedDebugMapPage8ContinuationException : Exception { }
+
+    private sealed class LaunchDebugMapAndStopAfterPage8Sink : ITraceSink
+    {
+        public VirtualMachine Vm = null!;
+        public bool TracingSteps => true;
+
+        public void Emit(in TraceEvent e)
+        {
+            if (e.Kind == TraceEventKind.FrameEnter
+                && e.Name?.Equals("TITLE.BIN", StringComparison.OrdinalIgnoreCase) == true)
+            {
+                DebugFrameSnapshot frame = Assert.IsType<DebugFrameSnapshot>(Vm.DebugFrame);
+                Assert.True(Vm.TryRequestDebugFrameReturn(frame.FrameId, new Dictionary<int, long>
+                {
+                    [0] = 1,
+                    [0xaba5c] = -1,
+                    [0x62ccf] = 0,
+                    [0x699] = 0x338c,
+                }));
+            }
+
+            if (e.Kind == TraceEventKind.Step
+                && e.Ins?.Offset == 0x5b25
+                && Vm.DebugFrame?.CurrentScript.Equals(
+                    "SC0270.BIN", StringComparison.OrdinalIgnoreCase) == true)
+                throw new ReachedDebugMapPage8ContinuationException();
+        }
+    }
+
     private static Operand I(long value) => new(0, value);
     private static Operand G(long address) => new(3, address);
     private static (int, Operand[]) Call(Operand id) => (0x3, new[] { id });
@@ -15,6 +45,24 @@ public class DebugSceneLaunchTests
     private static (int, Operand[]) Sleep() => (0xc8, new[] { I(1) });
     private static (int, Operand[]) Exit() => (0x2, Array.Empty<Operand>());
 
+    [Fact]
+    [Trait("Category", "Workspace")]
+    public void RealDebugMapLaunchContinuesPastSc0270Page8Wait()
+    {
+        var table = OpcodeTableJson.Load(Paths.OpcodesJson);
+        var scripts = Sys4ScriptProvider.Load(table);
+        var sink = new LaunchDebugMapAndStopAfterPage8Sink();
+        var vm = new VirtualMachine(
+            scripts.RequireByName("SYSTEM4.BIN"), table, new CaptureHost(),
+            new VmOptions(MaxSteps: 1_000_000), scripts, sink);
+        sink.Vm = vm;
+
+        Exception? exception = Record.Exception(() => vm.Run());
+
+        Assert.IsType<ReachedDebugMapPage8ContinuationException>(exception);
+        Assert.Null(vm.HaltReason);
+    }
+
     [Fact]
     public async Task ParkedTitleFrameReturnsToCoordinatorWhichDispatchesSelectedScript()
     {

engine/Age.Engine.Tests/WindowsGdiGlyphMaskRasterizerTests.cs

@@ -60,6 +60,19 @@ public class WindowsGdiGlyphMaskRasterizerTests
         Assert.All(actual.Coverage.ToArray(), value => Assert.InRange(value, (byte)0, (byte)16));
     }
 
+    [Fact]
+    public void IdeographicSpacePreservesAdvanceWithTransparentCoverage()
+    {
+        if (!WindowsGdiGlyphMaskRasterizer.TryGetAvailability(out _)) return;
+
+        using var rasterizer = new WindowsGdiGlyphMaskRasterizer();
+        GlyphMask space = rasterizer.Rasterize(
+            NativeRequest("ＭＳ 明朝", 24, -12, 0, 0x3000));
+
+        Assert.True(space.CellAdvanceX > 0);
+        Assert.All(space.Coverage.ToArray(), value => Assert.Equal(0, value));
+    }
+
     [Fact]
     public void FontHandlesUseTheSharedBoundedLruAndDisposeCleanly()
     {

engine/Age.Engine.Text.Windows/WindowsGdiGlyphMaskRasterizer.cs

@@ -124,7 +124,11 @@ public sealed class WindowsGdiGlyphMaskRasterizer
         int height = checked((int)metrics.BlackBoxY);
         int stride = checked((width + 3) & ~3);
         int expectedBytes = checked(stride * height);
-        if (size != expectedBytes)
+        // CP932 0x8140 (U+3000 IDEOGRAPHIC SPACE) is a zero-ink spacing glyph. GDI reports
+        // its placement as a nominal 1x1 black box but returns a zero-byte required buffer.
+        // Preserve those metrics and materialize the implied transparent mask; a nonzero
+        // short/oversized payload still means that the bitmap contract is inconsistent.
+        if (size != 0 && size != expectedBytes)
             throw new InvalidOperationException(
                 $"GDI gray-4 buffer size {size} disagrees with {width}x{height}, stride {stride}.");