[Ide] Optimize text editor drawing with selection

This avoid allocating a delegate for each time a render is issued when something is selected. (scroll, etc)

3 files changed, 56 insertions, 8 deletions

diff --git a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/HexEditorMargin.cs b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/HexEditorMargin.cs
index 9f5f74925d..d88c72b109 100644
--- a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/HexEditorMargin.cs
+++ b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/HexEditorMargin.cs
@@ -102,14 +102,18 @@ namespace Mono.MHex.Rendering
 			Margin.LayoutWrapper result = new LayoutWrapper (layout);
 			if (Data.IsSomethingSelected) {
 				ISegment selection = Data.MainSelection.Segment;
-				HandleSelection (selection.Offset, selection.EndOffset, startOffset, endOffset, null, delegate(long start, long end) {
-					result.Layout.SetForeground (Style.Selection, (int)(start - startOffset) * 3, (int)(end - start) * 3 - 1);
-					result.Layout.SetBackground (Style.SelectionBg, (int)(start - startOffset) * 3, (int)(end - start) * 3 - 1);
-				});
+				HandleSelection (selection.Offset, selection.EndOffset, startOffset, endOffset, this, new LayoutOffsetPair(startOffset, result.Layout), null, OnSelected);
 			}
 			return result;
 		}
 
+		static void OnSelected (long start, long end, Margin margin, LayoutOffsetPair arg)
+		{
+			var style = ((HexEditorMargin)margin).Style;

+			arg.Layout.SetForeground (style.Selection, (int)(start - arg.StartOffset) * 3, (int)(end - start) * 3 - 1);

+			arg.Layout.SetBackground (style.SelectionBg, (int)(start - arg.StartOffset) * 3, (int)(end - start) * 3 - 1);
+		}
+
 		uint TranslateColumn (long column)
 		{
 			return (uint)(column * 3);
diff --git a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/Margin.cs b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/Margin.cs
index d57aad8255..f0022c5803 100644
--- a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/Margin.cs
+++ b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/Margin.cs
@@ -192,6 +192,46 @@ namespace Mono.MHex.Rendering
 					handleNotSelected (startOffset, endOffset);
 			}
 		}
+
+		protected delegate void HandleSelectionArgsDelegate<T> (long start, long end, Margin margin, T arg);
+		protected struct LayoutOffsetPair
+		{
+			public readonly long StartOffset;
+			public readonly TextLayout Layout;
+
+			public LayoutOffsetPair (long startOffset, TextLayout layout)
+			{
+				StartOffset = startOffset;
+				Layout = layout;
+			}
+		}

+		protected static void HandleSelection<T> (long selectionStart, long selectionEnd, long startOffset, long endOffset, Margin margin, T args, HandleSelectionArgsDelegate<T> handleNotSelected, HandleSelectionArgsDelegate<T> handleSelected)
+		{
+			if (startOffset >= selectionStart && endOffset <= selectionEnd) {
+				if (handleSelected != null)
+					handleSelected (startOffset, endOffset, margin, args);
+			} else if (startOffset >= selectionStart && startOffset < selectionEnd && endOffset > selectionEnd) {
+				if (handleSelected != null)
+					handleSelected (startOffset, selectionEnd, margin, args);
+				if (handleNotSelected != null)
+					handleNotSelected (selectionEnd, endOffset, margin, args);
+			} else if (startOffset < selectionStart && endOffset > selectionStart && endOffset <= selectionEnd) {
+				if (handleNotSelected != null)
+					handleNotSelected (startOffset, selectionStart, margin, args);
+				if (handleSelected != null)
+					handleSelected (selectionStart, endOffset, margin, args);
+			} else if (startOffset < selectionStart && endOffset > selectionEnd) {
+				if (handleNotSelected != null)
+					handleNotSelected (startOffset, selectionStart, margin, args);
+				if (handleSelected != null)
+					handleSelected (selectionStart, selectionEnd, margin, args);
+				if (handleNotSelected != null)
+					handleNotSelected (selectionEnd, endOffset, margin, args);
+			} else {
+				if (handleNotSelected != null)
+					handleNotSelected (startOffset, endOffset, margin, args);
+			}
+		}
 		
 		protected static uint TranslateToUTF8Index (char[] charArray, uint textIndex, ref uint curIndex, ref uint byteIndex)
 		{
diff --git a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/TextEditorMargin.cs b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/TextEditorMargin.cs
index 930a3a470b..ccdce7df99 100644
--- a/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/TextEditorMargin.cs
+++ b/main/src/addins/MonoDevelop.HexEditor/Mono.MHex.Rendering/TextEditorMargin.cs
@@ -105,14 +105,18 @@ namespace Mono.MHex.Rendering
 			Margin.LayoutWrapper result = new LayoutWrapper (layout);
 			if (Data.IsSomethingSelected) {
 				ISegment selection = Data.MainSelection.Segment;
-				HandleSelection (selection.Offset, selection.EndOffset, startOffset, endOffset, null, delegate(long start, long end) {
-					result.Layout.SetForeground (Style.Selection, (int)(start - startOffset)/2, (int)(end - start)/2);
-					result.Layout.SetBackground (Style.SelectionBg, (int)(start - startOffset)/2, (int)(end - start)/2);
-				});
+				HandleSelection (selection.Offset, selection.EndOffset, startOffset, endOffset, this, new LayoutOffsetPair (startOffset, result.Layout), null, OnSelected);
 			}
 			return result;
 		}
 
+		static void OnSelected (long start, long end, Margin margin, LayoutOffsetPair arg)
+		{
+			var style = ((TextEditorMargin)margin).Style;
+			arg.Layout.SetForeground (style.Selection, (int)(start - arg.StartOffset) / 2, (int)(end - start) / 2);

+			arg.Layout.SetBackground (style.SelectionBg, (int)(start - arg.StartOffset) / 2, (int)(end - start) / 2);
+		}
+
 		internal protected override void Draw (Context ctx, Rectangle area, long line, double x, double y)
 		{
 			ctx.Rectangle (x, y, Width, Editor.LineHeight);