Add wireframe mode

samples/TestApp/Views/MainView.axaml

@@ -143,6 +143,10 @@
                       OffContent="Hide Bounds"
                       Margin="6,0,6,0"
                       Click="ShowHitBoundsToggle_OnToggled" />
+        <ToggleSwitch IsChecked="{Binding #Svg.Wireframe}"
+                      OnContent="Wireframe On"
+                      OffContent="Wireframe Off"
+                      Margin="6,0,6,0" />
         <Button Content="Export"
                 Command="{Binding ExportCommand}"
                 CommandParameter="{Binding #Svg}"

src/Svg.Controls.Skia.Avalonia/Svg.cs

@@ -24,6 +24,7 @@ public class Svg : Control
     private readonly Uri _baseUri;
     private SvgSource? _svg;
     private bool _enableCache;
+    private bool _wireframe;
     private Dictionary<string, SvgSource>? _cache;
 
     /// <summary>
@@ -60,6 +61,14 @@ public class Svg : Control
             o => o.EnableCache,
             (o, v) => o.EnableCache = v);
 
+    /// <summary>
+    /// Defines the <see cref="Wireframe"/> property.
+    /// </summary>
+    public static readonly DirectProperty<Svg, bool> WireframeProperty =
+        AvaloniaProperty.RegisterDirect<Svg, bool>(nameof(Wireframe),
+            o => o.Wireframe,
+            (o, v) => o.Wireframe = v);
+
     /// <summary>
     /// Defines the Css property.
     /// </summary>
@@ -118,6 +127,15 @@ public bool EnableCache
         set { SetAndRaise(EnableCacheProperty, ref _enableCache, value); }
     }
 
+    /// <summary>
+    /// Gets or sets a value controlling wireframe rendering mode.
+    /// </summary>
+    public bool Wireframe
+    {
+        get { return _wireframe; }
+        set { SetAndRaise(WireframeProperty, ref _wireframe, value); }
+    }
+
     /// <summary>
     /// Gets svg picture.
     /// </summary>
@@ -374,6 +392,16 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                 _cache = new Dictionary<string, SvgSource>();
             }
         }
+
+        if (change.Property == WireframeProperty)
+        {
+            if (_svg?.Svg is { } skSvg)
+            {
+                skSvg.Wireframe = change.GetNewValue<bool>();
+                skSvg.ClearWireframePicture();
+            }
+            InvalidateVisual();
+        }
     }
 
     private void LoadFromPath(string? path, SvgParameters? parameters = null)
@@ -389,6 +417,11 @@ private void LoadFromPath(string? path, SvgParameters? parameters = null)
         if (_enableCache && _cache is { } && _cache.TryGetValue(path, out var svg))
         {
             _svg = svg;
+            if (_svg.Svg is { } skSvg)
+            {
+                skSvg.Wireframe = _wireframe;
+                skSvg.ClearWireframePicture();
+            }
             return;
         }
 
@@ -401,6 +434,11 @@ private void LoadFromPath(string? path, SvgParameters? parameters = null)
         try
         {
             _svg = SvgSource.Load(path, _baseUri, parameters);
+            if (_svg?.Svg is { } skSvg2)
+            {
+                skSvg2.Wireframe = _wireframe;
+                skSvg2.ClearWireframePicture();
+            }
 
             if (_enableCache && _cache is { } && _svg is { })
             {
@@ -429,6 +467,11 @@ private void LoadFromSource(string? source, SvgParameters? parameters = null)
             var bytes = Encoding.UTF8.GetBytes(source);
             using var ms = new MemoryStream(bytes);
             _svg = SvgSource.LoadFromStream(ms, parameters);
+            if (_svg?.Svg is { } skSvg)
+            {
+                skSvg.Wireframe = _wireframe;
+                skSvg.ClearWireframePicture();
+            }
         }
         catch (Exception e)
         {

src/Svg.Skia/SKSvg.Model.cs

@@ -102,6 +102,25 @@ public static void Draw(SkiaSharp.SKCanvas skCanvas, string path, SkiaModel skia
 
     public virtual SkiaSharp.SKPicture? Picture { get; protected set; }
 
+    public SkiaSharp.SKPicture? WireframePicture { get; protected set; }
+
+    private bool _wireframe;
+    public bool Wireframe
+    {
+        get => _wireframe;
+        set
+        {
+            _wireframe = value;
+            ClearWireframePicture();
+        }
+    }
+
+    public void ClearWireframePicture()
+    {
+        WireframePicture?.Dispose();
+        WireframePicture = null;
+    }
+
     public event EventHandler<SKSvgDrawEventArgs>? OnDraw;
 
     protected virtual void RaiseOnDraw(SKSvgDrawEventArgs e)
@@ -153,6 +172,8 @@ public SKSvg()
         Model = SvgService.ToModel(svgDocument, AssetLoader, out var drawable, out _);
         Drawable = drawable;
         Picture = SkiaModel.ToSKPicture(Model);
+        WireframePicture?.Dispose();
+        WireframePicture = null;
 
         return Picture;
     }
@@ -174,6 +195,8 @@ public SKSvg()
         Model = SvgService.ToModel(svgDocument, AssetLoader, out var drawable, out _);
         Drawable = drawable;
         Picture = SkiaModel.ToSKPicture(Model);
+        WireframePicture?.Dispose();
+        WireframePicture = null;
 
         return Picture;
     }
@@ -188,6 +211,8 @@ public SKSvg()
             Model = SvgService.ToModel(svgDocument, AssetLoader, out var drawable, out _);
             Drawable = drawable;
             Picture = SkiaModel.ToSKPicture(Model);
+            WireframePicture?.Dispose();
+            WireframePicture = null;
             return Picture;
         }
         return null;
@@ -225,6 +250,8 @@ public SKSvg()
             Model = SvgService.ToModel(svgDocument, AssetLoader, out var drawable, out _);
             Drawable = drawable;
             Picture = SkiaModel.ToSKPicture(Model);
+            WireframePicture?.Dispose();
+            WireframePicture = null;
             return Picture;
         }
         return null;
@@ -237,6 +264,8 @@ public SKSvg()
             Model = SvgService.ToModel(svgDocument, AssetLoader, out var drawable, out _);
             Drawable = drawable;
             Picture = SkiaModel.ToSKPicture(Model);
+            WireframePicture?.Dispose();
+            WireframePicture = null;
             return Picture;
         }
         return null;
@@ -270,7 +299,18 @@ public void Draw(SkiaSharp.SKCanvas canvas)
         }
 
         canvas.Save();
-        canvas.DrawPicture(picture);
+        if (Wireframe && Model is { })
+        {
+            WireframePicture ??= SkiaModel.ToWireframePicture(Model);
+            if (WireframePicture is { })
+            {
+                canvas.DrawPicture(WireframePicture);
+            }
+        }
+        else
+        {
+            canvas.DrawPicture(picture);
+        }
         canvas.Restore();
 
         RaiseOnDraw(new SKSvgDrawEventArgs(canvas));
@@ -285,6 +325,9 @@ private void Reset()
 
             Picture?.Dispose();
             Picture = null;
+
+            WireframePicture?.Dispose();
+            WireframePicture = null;
         }
     }
 

src/Svg.Skia/SkiaModel.cs

@@ -915,7 +915,7 @@
         };
     }
 
     public SkiaSharp.SKFilterQuality ToSKFilterQuality(SKFilterQuality filterQuality)
     {
         return filterQuality switch
         {
@@ -1246,7 +1246,23 @@
         return skPictureRecorder.EndRecording();
     }
 
-    public void Draw(CanvasCommand canvasCommand, SkiaSharp.SKCanvas skCanvas)
+    public SkiaSharp.SKPicture? ToWireframePicture(SKPicture? picture)
+    {
+        if (picture is null)
+        {
+            return null;
+        }
+
+        var skRect = ToSKRect(picture.CullRect);
+        using var skPictureRecorder = new SkiaSharp.SKPictureRecorder();
+        using var skCanvas = skPictureRecorder.BeginRecording(skRect);
+
+        Draw(picture, skCanvas, true);
+
+        return skPictureRecorder.EndRecording();
+    }
+
+    public void Draw(CanvasCommand canvasCommand, SkiaSharp.SKCanvas skCanvas, bool wireframe = false)
     {
         switch (canvasCommand)
         {
@@ -1289,7 +1305,9 @@
             {
                 if (saveLayerCanvasCommand.Paint is { })
                 {
-                    var paint = ToSKPaint(saveLayerCanvasCommand.Paint);
+                    var paint = wireframe
+                        ? ToWireframePaint(saveLayerCanvasCommand.Paint)
+                        : ToSKPaint(saveLayerCanvasCommand.Paint);
                     skCanvas.SaveLayer(paint);
                 }
                 else
@@ -1302,11 +1320,20 @@
             {
                 if (drawImageCanvasCommand.Image is { })
                 {
-                    var image = ToSKImage(drawImageCanvasCommand.Image);
-                    var source = ToSKRect(drawImageCanvasCommand.Source);
-                    var dest = ToSKRect(drawImageCanvasCommand.Dest);
-                    var paint = ToSKPaint(drawImageCanvasCommand.Paint);
-                    skCanvas.DrawImage(image, source, dest, paint);
+                    if (wireframe)
+                    {
+                        var rectPath = new SkiaSharp.SKPath();
+                        rectPath.AddRect(ToSKRect(drawImageCanvasCommand.Dest));
+                        skCanvas.DrawPath(rectPath, ToWireframePaint(null));
+                    }
+                    else
+                    {
+                        var image = ToSKImage(drawImageCanvasCommand.Image);
+                        var source = ToSKRect(drawImageCanvasCommand.Source);
+                        var dest = ToSKRect(drawImageCanvasCommand.Dest);
+                        var paint = ToSKPaint(drawImageCanvasCommand.Paint);
+                        skCanvas.DrawImage(image, source, dest, paint);
+                    }
                 }
                 break;
             }
@@ -1315,7 +1342,9 @@
                 if (drawPathCanvasCommand.Path is { } && drawPathCanvasCommand.Paint is { })
                 {
                     var path = ToSKPath(drawPathCanvasCommand.Path);
-                    var paint = ToSKPaint(drawPathCanvasCommand.Paint);
+                    var paint = wireframe
+                        ? ToWireframePaint(drawPathCanvasCommand.Paint)
+                        : ToSKPaint(drawPathCanvasCommand.Paint);
                     skCanvas.DrawPath(path, paint);
                 }
                 break;
@@ -1326,7 +1355,9 @@
                 {
                     var text = drawPositionedTextCanvasCommand.TextBlob.Text;
                     var points = ToSKPoints(drawPositionedTextCanvasCommand.TextBlob.Points);
-                    var paint = ToSKPaint(drawPositionedTextCanvasCommand.Paint);
+                    var paint = wireframe
+                        ? ToWireframePaint(drawPositionedTextCanvasCommand.Paint)
+                        : ToSKPaint(drawPositionedTextCanvasCommand.Paint);
                     var font = paint?.ToFont();
                     var textBlob = SkiaSharp.SKTextBlob.CreatePositioned(text, font, points);
                     skCanvas.DrawText(textBlob, 0, 0, paint);
@@ -1340,7 +1371,9 @@
                     var text = drawTextCanvasCommand.Text;
                     var x = drawTextCanvasCommand.X;
                     var y = drawTextCanvasCommand.Y;
-                    var paint = ToSKPaint(drawTextCanvasCommand.Paint);
+                    var paint = wireframe
+                        ? ToWireframePaint(drawTextCanvasCommand.Paint)
+                        : ToSKPaint(drawTextCanvasCommand.Paint);
                     skCanvas.DrawText(text, x, y, paint);
                 }
                 break;
@@ -1353,15 +1386,17 @@
                     var path = ToSKPath(drawTextOnPathCanvasCommand.Path);
                     var hOffset = drawTextOnPathCanvasCommand.HOffset;
                     var vOffset = drawTextOnPathCanvasCommand.VOffset;
-                    var paint = ToSKPaint(drawTextOnPathCanvasCommand.Paint);
+                    var paint = wireframe
+                        ? ToWireframePaint(drawTextOnPathCanvasCommand.Paint)
+                        : ToSKPaint(drawTextOnPathCanvasCommand.Paint);
                     skCanvas.DrawTextOnPath(text, path, hOffset, vOffset, paint);
                 }
                 break;
             }
         }
     }
 
-    public void Draw(SKPicture picture, SkiaSharp.SKCanvas skCanvas)
+    public void Draw(SKPicture picture, SkiaSharp.SKCanvas skCanvas, bool wireframe = false)
     {
         if (picture.Commands is null)
         {
@@ -1370,7 +1405,48 @@
 
         foreach (var canvasCommand in picture.Commands)
         {
-            Draw(canvasCommand, skCanvas);
+            Draw(canvasCommand, skCanvas, wireframe);
         }
     }
+
+    private SkiaSharp.SKPaint ToWireframePaint(SKPaint? paint)
+    {
+        var strokeCap = paint is null ? SkiaSharp.SKStrokeCap.Butt : ToSKStrokeCap(paint.StrokeCap);
+        var strokeJoin = paint is null ? SkiaSharp.SKStrokeJoin.Miter : ToSKStrokeJoin(paint.StrokeJoin);
+        var textAlign = paint is null ? SkiaSharp.SKTextAlign.Left : ToSKTextAlign(paint.TextAlign);
+        var typeface = paint is null ? null : ToSKTypeface(paint.Typeface);
+        var textEncoding = paint is null ? SkiaSharp.SKTextEncoding.Utf8 : ToSKTextEncoding(paint.TextEncoding);
+        var colorFilter = paint is null ? null : ToSKColorFilter(paint.ColorFilter);
+        var imageFilter = paint is null ? null : ToSKImageFilter(paint.ImageFilter);
+        var pathEffect = paint is null ? null : ToSKPathEffect(paint.PathEffect);
+        var blendMode = paint is null ? SkiaSharp.SKBlendMode.SrcOver : ToSKBlendMode(paint.BlendMode);
+        var filterQuality = paint is null ? SkiaSharp.SKFilterQuality.None : ToSKFilterQuality(paint.FilterQuality);
+
+        return new SkiaSharp.SKPaint
+        {
+            Style = SkiaSharp.SKPaintStyle.Stroke,
+            IsAntialias = paint?.IsAntialias ?? false,
+            StrokeWidth = 0,
+            StrokeCap = strokeCap,
+            StrokeJoin = strokeJoin,
+            StrokeMiter = paint?.StrokeMiter ?? 4,
+            TextSize = paint?.TextSize ?? 0,
+            TextAlign = textAlign,
+            Typeface = typeface,
+            LcdRenderText = paint?.LcdRenderText ?? false,
+            SubpixelText = paint?.SubpixelText ?? false,
+            TextEncoding = textEncoding,
+            Color = new SkiaSharp.SKColor(128, 128, 128, 255),
+            ColorFilter = colorFilter,
+            ImageFilter = imageFilter,
+            PathEffect = pathEffect,
+            BlendMode = blendMode,
+            FilterQuality = filterQuality
+        };
+    }
+
+    public void DrawWireframe(SKPicture picture, SkiaSharp.SKCanvas skCanvas)
+    {
+        Draw(picture, skCanvas, true);
+    }
 }