engine: add deterministic glyph mask core

2026-07-30 18:25:46 -04:00
parent 41001f6f77
commit 7397e4e5fb
9 changed files with 818 additions and 8 deletions
--- a/engine/Age.Engine/Text/RetainedGlyphLayoutEngine.cs
+++ b/engine/Age.Engine/Text/RetainedGlyphLayoutEngine.cs
@@ -0,0 +1,91 @@
+using Age.Engine.Model;
+using Age.Engine.Sys4;
+
+namespace Age.Engine.Text;
+
+public readonly record struct GlyphTextLayoutOptions(
+    int CursorX,
+    int CursorY,
+    int LineOriginX,
+    int RightBound,
+    int BottomBound,
+    bool WrapHorizontally,
+    AdvTextStyle Style);
+
+public sealed record GlyphTextLayoutResult(
+    IReadOnlyList<AdvRetainedGlyphRecord> Records,
+    int CursorX,
+    int CursorY,
+    int ConsumedGlyphs,
+    int WrappedLines,
+    AdvTextOverflowFlags ObservedOverflow,
+    bool StoppedOnVerticalOverflow);
+
+/// <summary>
+/// Builds native-edge retained records while rasterizing masks into the layout's RGBA surface.
+/// This is deliberately presentation-neutral: binding records to GfxState belongs to a later slice.
+/// </summary>
+public sealed class RetainedGlyphLayoutEngine
+{
+    private readonly IGlyphMaskRasterizer _rasterizer;
+
+    public RetainedGlyphLayoutEngine(IGlyphMaskRasterizer rasterizer)
+        => _rasterizer = rasterizer ?? throw new ArgumentNullException(nameof(rasterizer));
+
+    public GlyphTextLayoutResult Render(
+        RgbaImage destination,
+        GlyphTextLayoutOptions options,
+        IReadOnlyList<GlyphRasterRequest> glyphs)
+    {
+        ArgumentNullException.ThrowIfNull(destination);
+        ArgumentNullException.ThrowIfNull(glyphs);
+        var records = new List<AdvRetainedGlyphRecord>(glyphs.Count);
+        int cursorX = options.CursorX;
+        int cursorY = options.CursorY;
+        int wrappedLines = 0;
+        var observed = AdvTextOverflowFlags.None;
+        bool stopped = false;
+
+        foreach (GlyphRasterRequest request in glyphs)
+        {
+            ArgumentNullException.ThrowIfNull(request);
+            GlyphMask mask = _rasterizer.Rasterize(request);
+            int right = checked(cursorX + mask.CellWidth);
+            int bottom = checked(cursorY + mask.CellHeight);
+            AdvTextOverflowFlags overflow = AdvRetainedTextContract.CheckOverflow(
+                options.RightBound, options.BottomBound, right, bottom);
+            observed |= overflow;
+
+            if (overflow == AdvTextOverflowFlags.Vertical)
+            {
+                stopped = true;
+                break;
+            }
+
+            if (overflow.HasFlag(AdvTextOverflowFlags.Horizontal)
+                && options.WrapHorizontally
+                && (request.Cp932Code == null
+                    || !AdvRetainedTextContract.PreventsHorizontalWrapBefore(
+                        request.Cp932Code.Value)))
+            {
+                int fontHeight = options.Style.PrimaryFontSize > 0
+                    ? options.Style.PrimaryFontSize
+                    : request.PixelHeight;
+                cursorX = options.LineOriginX;
+                cursorY = checked(cursorY + fontHeight + options.Style.LineSpacing);
+                wrappedLines++;
+                right = checked(cursorX + mask.CellWidth);
+                bottom = checked(cursorY + mask.CellHeight);
+            }
+
+            AgeGlyphMaskCompositor.DrawGlyph(
+                destination, mask, cursorX, cursorY, request.PixelHeight, options.Style);
+            records.Add(new AdvRetainedGlyphRecord(0, cursorX, cursorY, right, bottom));
+            cursorX = checked(cursorX + mask.CellAdvanceX);
+            cursorY = checked(cursorY + mask.CellAdvanceY);
+        }
+
+        return new GlyphTextLayoutResult(
+            records, cursorX, cursorY, records.Count, wrappedLines, observed, stopped);
+    }
+}