IsAntialias should also control the Edging

binding/Binding/SKPaint.cs

@@ -14,6 +14,7 @@ public enum SKPaintHinting
 	public unsafe class SKPaint : SKObject, ISKSkipObjectRegistration
 	{
 		private SKFont font;
+		private bool lcdRenderText;
 
 		internal SKPaint (IntPtr handle, bool owns)
 			: base (handle, owns)
@@ -38,6 +39,8 @@ public SKPaint (SKFont font)
 
 			if (Handle == IntPtr.Zero)
 				throw new InvalidOperationException ("Unable to create a new SKPaint instance.");
+
+			LcdRenderText = font.Edging == SKFontEdging.SubpixelAntialias;
 		}
 
 		protected override void Dispose (bool disposing) =>
@@ -55,7 +58,10 @@ public void Reset () =>
 
 		public bool IsAntialias {
 			get => SkiaApi.sk_paint_is_antialias (Handle);
-			set => SkiaApi.sk_paint_set_antialias (Handle, value);
+			set {
+				SkiaApi.sk_paint_set_antialias (Handle, value);
+				UpdateFontEdging (value);
+			}
 		}
 
 		public bool IsDither {
@@ -81,8 +87,11 @@ public bool SubpixelText {
 		}
 
 		public bool LcdRenderText {
-			get => GetFont ().Edging == SKFontEdging.SubpixelAntialias;
-			set => GetFont ().Edging = value ? SKFontEdging.SubpixelAntialias : SKFontEdging.Antialias;
+			get => lcdRenderText;
+			set {
+				lcdRenderText = value;
+				UpdateFontEdging (IsAntialias);
+			}
 		}
 
 		public bool IsEmbeddedBitmapText {
@@ -701,6 +710,17 @@ public SKFont ToFont () =>
 		internal SKFont GetFont () =>
 			font ??= OwnedBy (SKFont.GetObject (SkiaApi.sk_compatpaint_get_font (Handle), false), this);
 
+		private void UpdateFontEdging (bool antialias)
+		{
+			var edging = SKFontEdging.Alias;
+			if (antialias) {
+				edging = lcdRenderText
+					? SKFontEdging.SubpixelAntialias
+					: SKFontEdging.Antialias;
+			}
+			GetFont ().Edging = edging;
+		}
+
 		//
 
 		internal static SKPaint GetObject (IntPtr handle) =>

tests/Tests/SKPaintTest.cs

@@ -554,5 +554,92 @@ public void GetTextPathSucceedsForEmtptyString()
 
 			Assert.NotNull(paint.GetTextPath("", 0, 0));
 		}
+
+		[SkippableTheory]
+		[InlineData(true, true, SKFontEdging.SubpixelAntialias)]
+		[InlineData(false, true, SKFontEdging.Alias)]
+		[InlineData(true, false, SKFontEdging.Antialias)]
+		[InlineData(false, false, SKFontEdging.Alias)]
+		public void UpdatingPropertiesIsAntialiasLcdRenderText(bool isAntialias, bool lcd, SKFontEdging newEdging)
+		{
+			var paint = new SKPaint();
+
+			paint.IsAntialias = isAntialias;
+			paint.LcdRenderText = lcd;
+
+			Assert.Equal(newEdging, paint.GetFont().Edging);
+		}
+
+		[SkippableTheory]
+		[InlineData(true, true, SKFontEdging.SubpixelAntialias)]
+		[InlineData(false, true, SKFontEdging.Alias)]
+		[InlineData(true, false, SKFontEdging.Antialias)]
+		[InlineData(false, false, SKFontEdging.Alias)]
+		public void UpdatingPropertiesLcdRenderTextIsAntialias(bool isAntialias, bool lcd, SKFontEdging newEdging)
+		{
+			var paint = new SKPaint();
+
+			paint.LcdRenderText = lcd;
+			paint.IsAntialias = isAntialias;
+
+			Assert.Equal(newEdging, paint.GetFont().Edging);
+		}
+
+		[SkippableFact]
+		public void PaintWithSubpixelEdgingIsPreserved()
+		{
+			var font = new SKFont();
+			font.Edging = SKFontEdging.SubpixelAntialias;
+
+			var paint = new SKPaint(font);
+
+			Assert.True(paint.LcdRenderText);
+			Assert.False(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.Alias, paint.GetFont().Edging);
+
+			paint.IsAntialias = true;
+
+			Assert.True(paint.LcdRenderText);
+			Assert.True(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.SubpixelAntialias, paint.GetFont().Edging);
+		}
+
+		[SkippableFact]
+		public void PaintWithAntialiasEdgingIsPreserved()
+		{
+			var font = new SKFont();
+			font.Edging = SKFontEdging.Antialias;
+
+			var paint = new SKPaint(font);
+
+			Assert.False(paint.LcdRenderText);
+			Assert.False(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.Alias, paint.GetFont().Edging);
+
+			paint.IsAntialias = true;
+
+			Assert.False(paint.LcdRenderText);
+			Assert.True(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.Antialias, paint.GetFont().Edging);
+		}
+
+		[SkippableFact]
+		public void PaintWithAliasEdgingIsPreserved()
+		{
+			var font = new SKFont();
+			font.Edging = SKFontEdging.Alias;
+
+			var paint = new SKPaint(font);
+
+			Assert.False(paint.LcdRenderText);
+			Assert.False(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.Alias, paint.GetFont().Edging);
+
+			paint.IsAntialias = true;
+
+			Assert.False(paint.LcdRenderText);
+			Assert.True(paint.IsAntialias);
+			Assert.Equal(SKFontEdging.Antialias, paint.GetFont().Edging);
+		}
 	}
 }