Merge pull request #2019 from cwensley/curtis/mac-add-nsimage-templat…

…e-drawing

Mac: Add ability to draw NSImage via Graphics when it is a template

src/Eto.Mac/Drawing/BitmapHandler.cs

@@ -260,6 +260,12 @@ public void Save(Stream stream, ImageFormat format)
 
 		public override void DrawImage(GraphicsHandler graphics, RectangleF source, RectangleF destination)
 		{
+			if (Control.Template)
+			{
+				DrawTemplateImage(graphics, source, destination);
+				return;
+			}
+
 			var sourceRect = new CGRect(source.X, (float)Control.Size.Height - source.Y - source.Height, source.Width, source.Height);
 			var destRect = destination.ToNS();
 			if (alpha)

src/Eto.Mac/Drawing/GraphicsHandler.cs

@@ -92,6 +92,8 @@ public class GraphicsHandler : GraphicsBase, Graphics.IHandler
 		public NSView DisplayView { get; private set; }
 
 		static readonly object PixelOffsetMode_Key = new object();
+
+		public NSGraphicsContext GraphicsContext => graphicsContext;
 
 		public PixelOffsetMode PixelOffsetMode
 		{

src/Eto.Mac/Drawing/IconHandler.cs

@@ -111,6 +111,12 @@ public override NSImage GetImage()
 
 		public override void DrawImage(GraphicsHandler graphics, RectangleF source, RectangleF destination)
 		{
+			if (Control.Template)
+			{
+				DrawTemplateImage(graphics, source, destination);
+				return;
+			}
+
 			var sourceRect = new CGRect(source.X, (float)Control.Size.Height - source.Y - source.Height, source.Width, source.Height);
 			var destRect = destination.ToNS();
 			Control.Draw(destRect, sourceRect, NSCompositingOperation.SourceOver, 1, true, null);

src/Eto.Mac/Drawing/ImageHandler.cs

@@ -48,8 +48,8 @@ interface IImageHandler : IImageSource
 	}
 
 	public abstract class ImageHandler<TControl, TWidget> : WidgetHandler<TControl, TWidget>, Image.IHandler, IImageHandler
-		where TControl: class
-		where TWidget: Image
+		where TControl : class
+		where TWidget : Image
 	{
 		public abstract Size Size { get; }
 
@@ -66,5 +66,50 @@ public virtual void DrawImage(GraphicsHandler graphics, float x, float y, float
 		}
 
 		public abstract void DrawImage(GraphicsHandler graphics, RectangleF source, RectangleF destination);
+
+
+		public virtual void DrawTemplateImage(GraphicsHandler graphics, RectangleF source, RectangleF destination)
+		{
+			var imageSize = Size;
+			// draw as a template image, and ignore color data
+			var ctx = graphics.Control;
+			ctx.SaveState();
+
+			RectangleF destMask;
+			if (destination.Size != source.Size)
+			{
+				// scale and position
+				var scale = destination.Size / source.Size;
+				destMask = new RectangleF(destination.Location - source.Location * scale, imageSize * scale);
+			}
+			else
+			{
+				// just position
+				destMask = new RectangleF(destination.Location - source.Location, imageSize);
+			}
+
+			var destRect = destination.ToNS();
+			var cgImage = GetImage().AsCGImage(ref destRect, graphics.GraphicsContext, null);
+
+			// clip to the image as a mask, using only alpha channel
+			ctx.ClipToMask(destMask.ToNS(), cgImage);
+
+			// set fill color based on current dark/light theme
+			// this is the best approximation I can find to get it to draw the same as NSImageView
+			// thus far..
+			NSColor color;
+			if (MacVersion.IsAtLeast(10, 14) && graphics.DisplayView.HasDarkTheme())
+			{
+				color = NSColor.FromWhite(1f, .55f);
+			}
+			else
+			{
+				color = NSColor.FromWhite(0, .5f);
+			}
+			color.SetFill();
+
+			ctx.FillRect(destRect);
+			ctx.RestoreState();
+		}
 	}
 }

src/Eto.Mac/Forms/MacControlExtensions.cs

@@ -121,6 +121,21 @@ public static void CenterInParent(this NSView view)
 				view.SetFrameOrigin(new CGPoint((nfloat)(superFrame.Width - size.Width) / 2, (nfloat)(superFrame.Height - size.Height) / 2));
 			}
 		}
+
+		public static bool HasDarkTheme(this NSView view)
+		{
+			if (!MacVersion.IsAtLeast(10, 14))
+				return false;
+
+			var appearance = view?.EffectiveAppearance ?? NSAppearance.CurrentAppearance;
+
+			var name = appearance.Name;
+
+			if (name == NSAppearance.NameDarkAqua || name == NSAppearance.NameAccessibilityHighContrastDarkAqua)
+				return true;
+
+			return false;
+		}
 	}
 }
 

test/Eto.Test.Mac/UnitTests/BitmapTests.cs

@@ -0,0 +1,69 @@
+using Eto.Drawing;
+using Eto.Forms;
+using Eto.Test.UnitTests;
+using NUnit.Framework;
+
+#if XAMMAC2
+using AppKit;
+using CoreGraphics;
+#else
+using MonoMac.AppKit;
+using MonoMac.CoreGraphics;
+#endif
+
+namespace Eto.Test.Mac.UnitTests
+{
+	[TestFixture]
+    public class BitmapTests : TestBase
+    {
+		[TestCase(null)]
+		[TestCase("Blue")]
+		[TestCase("White")]
+		[TestCase("Black")]
+		[ManualTest]
+        public void TemplateImagesShouldDrawCorrectly(string color)
+		{
+			ManualForm("Both images should be the same in both light and dark mode",
+			form => {
+				
+				Color? backgroundColor = color != null ? Color.Parse(color) : (Color?)null;
+				var bmp = new Bitmap(200, 200, PixelFormat.Format32bppRgba);
+				var img = bmp.ControlObject as NSImage;
+				img.Template = true;
+				using (var g = new Graphics(bmp))
+				{
+					g.PixelOffsetMode = PixelOffsetMode.Half;
+					g.FillRectangle(new Color(Colors.Black, .5f), 39, 39, 120, 120);
+
+					g.DrawRectangle(Colors.Red, 4.5f, 4.5f, 191, 191);
+					g.FillRectangle(Colors.Red, 49, 49, 100, 100);
+
+
+					g.DrawRectangle(Colors.Black, 0.5f, 0.5f, 199, 199);
+					g.FillRectangle(Colors.Black, 59, 59, 80, 80);
+					
+				}
+				
+				var drawable = new Drawable { Size = bmp.Size };
+				drawable.Paint += (sender, e) => {
+					if (backgroundColor != null)
+						e.Graphics.Clear(backgroundColor.Value);
+					e.Graphics.DrawImage(bmp, 0, 0);
+					// e.Graphics.DrawImage(bmp, 50, 50, 100, 100);
+					// e.Graphics.DrawImage(bmp, new RectangleF(99, 99, 100, 100), new Rectangle(0, 0, 200, 200));
+				};
+				
+				var imageView = new ImageView();
+				imageView.Image = bmp;
+				if (backgroundColor != null)
+					imageView.BackgroundColor = backgroundColor.Value;
+				
+				var content = new DynamicLayout();
+				content.AddRow(drawable, imageView, null);
+				content.AddSpace();
+				return content;	
+			}
+			);
+		}
+    }
+}