支持共享渲染器减少内存分配

Author: lindexi

src/DotNetCampus.AvaloniaInkCanvas/Contexts/DynamicStrokeContext.cs

@@ -7,16 +7,26 @@ namespace DotNetCampus.Inking.Contexts;
 /// </summary>
 class DynamicStrokeContext
 {
-    public DynamicStrokeContext(InkingModeInputArgs lastInputArgs, AvaloniaSkiaInkCanvasSettings settings)
+    public DynamicStrokeContext(InkingModeInputArgs lastInputArgs, AvaloniaSkiaInkCanvas canvas)
     {
         LastInputArgs = lastInputArgs;
 
+        var settings = canvas.Context.Settings;
+
+        SkiaSimpleInkRender? simpleInkRender = null;
+
+        if(settings.InkStrokeRenderer is null)
+        {
+            simpleInkRender = canvas.SimpleInkRender;
+        }
+
         Stroke = new SkiaStroke(InkId.NewId())
         {
             Color = settings.InkColor,
             InkThickness = settings.InkThickness,
             IgnorePressure = settings.IgnorePressure,
             InkStrokeRenderer = settings.InkStrokeRenderer,
+            SimpleInkRender = simpleInkRender,
         };
     }
 

src/DotNetCampus.AvaloniaInkCanvas/Core/AvaloniaSkiaInkCanvas.cs

@@ -74,6 +74,12 @@ public AvaloniaSkiaInkCanvas()
     /// </summary>
     public AvaloniaSkiaInkCanvasSettings Settings => Context.Settings;
 
+    /// <summary>
+    /// 共享的简单笔迹渲染器
+    /// </summary>
+    internal SkiaSimpleInkRender SimpleInkRender => _skiaSimpleInkRender ??= new SkiaSimpleInkRender();
+    private SkiaSimpleInkRender? _skiaSimpleInkRender;
+
     internal void AddChild(Control childControl)
     {
         LogicalChildren.Add(childControl);
@@ -107,7 +113,7 @@ public void WritingDown(in InkingModeInputArgs args)
     {
         EnsureInputConflicts();
 
-        var dynamicStrokeContext = new DynamicStrokeContext(args, Context.Settings);
+        var dynamicStrokeContext = new DynamicStrokeContext(args, this);
         _contextDictionary[args.Id] = dynamicStrokeContext;
         dynamicStrokeContext.Stroke.AddPoint(args.StylusPoint);
 

src/DotNetCampus.AvaloniaInkCanvas/Core/SkiaStroke.cs

@@ -1,4 +1,5 @@
-using Avalonia;
+using System.Diagnostics.CodeAnalysis;
+using Avalonia;
 using Avalonia.Skia;
 using DotNetCampus.Inking.Contexts;
 using DotNetCampus.Inking.Primitive;
@@ -102,6 +103,21 @@ public void AddPoints(in IEnumerable<InkStylusPoint> points)
         RenderInk(pointList);
     }
 
+    [AllowNull]
+    internal SkiaSimpleInkRender SimpleInkRender
+    {
+        get
+        {
+            return _skiaSimpleInkRender ??= new SkiaSimpleInkRender();
+        }
+        init
+        {
+            _skiaSimpleInkRender = value;
+        }
+    }
+
+    private SkiaSimpleInkRender? _skiaSimpleInkRender;
+
     private void RenderInk(List<InkStylusPoint> pointList)
     {
         if (InkStrokeRenderer is not null)
@@ -114,10 +130,10 @@ private void RenderInk(List<InkStylusPoint> pointList)
         {
             if (pointList.Count >= 2)
             {
-                var outlinePointList = SimpleInkRender.GetOutlinePointList(pointList, InkThickness);
+                var outlinePointList = SimpleInkRender.GetOutlineSKPointList(pointList, InkThickness);
 
                 Path.Reset();
-                Path.AddPoly(outlinePointList.Select(t => new SKPoint((float) t.X, (float) t.Y)).ToArray());
+                Path.AddPoly(outlinePointList);
             }
             else if (pointList.Count == 1)
             {
@@ -206,6 +222,8 @@ internal void SetAsStatic()
     {
         _drawBounds = GetDrawBounds();
         _isStaticStroke = true;
+        // 不再需要渲染了，释放渲染器
+        _skiaSimpleInkRender = null;
     }
 
     public static SkiaStroke CreateStaticStroke(InkId id, SKPath path, StylusPointListSpan pointList, SKColor color,
@@ -256,10 +274,10 @@ public void ApplyTransform(SimilarityTransformation2D transform)
 
         if (_pointList.Count > 2)
         {
-            var outlinePointList = SimpleInkRender.GetOutlinePointList(_pointList, InkThickness);
+            var outlinePointList = SimpleInkRender.GetOutlineSKPointList(_pointList, InkThickness);
 
             Path.Reset();
-            Path.AddPoly(outlinePointList.Select(t => new SKPoint((float) t.X, (float) t.Y)).ToArray());
+            Path.AddPoly(outlinePointList);
         }
 
         Transform = SKMatrix.Identity;