SD-1592: color for non-printable characters is now customisable

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CustomizableHighlightingColorizer.cs

@@ -22,6 +22,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 	{
 		public const string DefaultTextAndBackground = "Default text/background";
 		public const string SelectedText = "Selected text";
+		public const string NonPrintableCharacters = "Non-printable characters";
 		
 		public static void ApplyCustomizationsToDefaultElements(TextEditor textEditor, IEnumerable<CustomizedHighlightingColor> customizations)
 		{
@@ -30,8 +31,10 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			textEditor.TextArea.ClearValue(TextArea.SelectionBorderProperty);
 			textEditor.TextArea.ClearValue(TextArea.SelectionBrushProperty);
 			textEditor.TextArea.ClearValue(TextArea.SelectionForegroundProperty);
+			textEditor.TextArea.TextView.ClearValue(TextView.NonPrintableCharacterBrushProperty);
 			bool assignedDefaultText = false;
 			bool assignedSelectedText = false;
+			bool assignedNonPrintableCharacter = false;
 			foreach (CustomizedHighlightingColor color in customizations) {
 				switch (color.Name) {
 					case DefaultTextAndBackground:
@@ -54,7 +57,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 							pen.Freeze();
 							textEditor.TextArea.SelectionBorder = pen;
 							SolidColorBrush back = new SolidColorBrush(color.Background.Value);
-							back.Opacity = 0.7;
+							back.Opacity = 0.7; // TODO : remove this constant, let the use choose the opacity.
 							back.Freeze();
 							textEditor.TextArea.SelectionBrush = back;
 						}
@@ -62,6 +65,14 @@ namespace ICSharpCode.AvalonEdit.AddIn
 							textEditor.TextArea.SelectionForeground = CreateFrozenBrush(color.Foreground.Value);
 						}
 						break;
+					case NonPrintableCharacters:
+						if (assignedNonPrintableCharacter)
+							continue;
+						assignedNonPrintableCharacter = true;
+						
+						if (color.Foreground != null)
+							textEditor.TextArea.TextView.NonPrintableCharacterBrush = CreateFrozenBrush(color.Foreground.Value);
+						break;
 				}
 			}
 		}

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/Options/HighlightingOptions.xaml.cs

@@ -139,6 +139,21 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			selectedText.PropertyChanged += item_PropertyChanged;
 			listBox.Items.Add(selectedText);
 			
+			// Create entry for "Non-printable characters"
+			IHighlightingItem nonPrintChars = new SimpleHighlightingItem(
+				CustomizableHighlightingColorizer.NonPrintableCharacters,
+				ta => {
+					ta.Document.Text = "	    \r \r\n \n";
+				})
+			{
+				Foreground = Colors.LightGray
+			};
+			nonPrintChars = new CustomizedHighlightingItem(customizationList, nonPrintChars, null, canSetFont: false, canSetBackground: false);
+			if (language != null)
+				nonPrintChars = new CustomizedHighlightingItem(customizationList, nonPrintChars, language, canSetFont: false);
+			nonPrintChars.PropertyChanged += item_PropertyChanged;
+			listBox.Items.Add(nonPrintChars);
+			
 			// Create entry for "Bracket highlight"
 			IHighlightingItem bracketHighlight = new SimpleHighlightingItem(
 				BracketHighlightRenderer.BracketHighlight,
@@ -157,7 +172,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 			};
 			bracketHighlight = new CustomizedHighlightingItem(customizationList, bracketHighlight, null, canSetFont: false);
 			if (language != null)
-				selectedText = new CustomizedHighlightingItem(customizationList, bracketHighlight, language, canSetFont: false);
+				bracketHighlight = new CustomizedHighlightingItem(customizationList, bracketHighlight, language, canSetFont: false);
 			bracketHighlight.PropertyChanged += item_PropertyChanged;
 			listBox.Items.Add(bracketHighlight);
 		}
@@ -203,6 +218,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.Options
 						textView.LineTransformers.Add(colorizer);
 					}
 					textEditor.Select(0, 0);
+					bracketHighlighter.SetHighlight(null);
 					item.ShowExample(textEditor.TextArea);
 				}
 			}

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/NewLineElementGenerator.cs

@@ -54,7 +54,7 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			} else {
 				return null;
 			}
-			return new NewLineTextElement(CurrentContext.TextView.cachedElements.GetSimpleLightGrayText(newlineText, CurrentContext));
+			return new NewLineTextElement(CurrentContext.TextView.cachedElements.GetTextForNonPrintableCharacter(newlineText, CurrentContext));
 		}
 		
 		sealed class NewLineTextElement : FormattedTextElement

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/SingleCharacterElementGenerator.cs

@@ -88,9 +88,9 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		{
 			char c = CurrentContext.Document.GetCharAt(offset);
 			if (ShowSpaces && c == ' ') {
-				return new SpaceTextElement(CurrentContext.TextView.cachedElements.GetSimpleLightGrayText("\u00B7", CurrentContext));
+				return new SpaceTextElement(CurrentContext.TextView.cachedElements.GetTextForNonPrintableCharacter("\u00B7", CurrentContext));
 			} else if (ShowTabs && c == '\t') {
-				return new TabTextElement(CurrentContext.TextView.cachedElements.GetSimpleLightGrayText("\u00BB", CurrentContext));
+				return new TabTextElement(CurrentContext.TextView.cachedElements.GetTextForNonPrintableCharacter("\u00BB", CurrentContext));
 			} else if (ShowBoxForControlCharacters && char.IsControl(c)) {
 				var p = new VisualLineElementTextRunProperties(CurrentContext.GlobalTextRunProperties);
 				p.SetForegroundBrush(Brushes.White);

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextView.cs

@@ -366,6 +366,17 @@ namespace ICSharpCode.AvalonEdit.Rendering
 		}
 		#endregion
 		
+		#region Brushes
+		public static readonly DependencyProperty NonPrintableCharacterBrushProperty =
+			DependencyProperty.Register("NonPrintableCharacterBrush", typeof(Brush), typeof(TextView),
+			                            new FrameworkPropertyMetadata(Brushes.LightGray));
+		
+		public Brush NonPrintableCharacterBrush {
+			get { return (Brush)GetValue(NonPrintableCharacterBrushProperty); }
+			set { SetValue(NonPrintableCharacterBrushProperty, value); }
+		}
+		#endregion
+		
 		#region Redraw methods / VisualLine invalidation
 		/// <summary>
 		/// Causes the text editor to regenerate all visual lines.
@@ -1660,7 +1671,8 @@ namespace ICSharpCode.AvalonEdit.Rendering
 			    || e.Property == Control.FontSizeProperty
 			    || e.Property == Control.FontStretchProperty
 			    || e.Property == Control.FontStyleProperty
-			    || e.Property == Control.FontWeightProperty)
+			    || e.Property == Control.FontWeightProperty
+			    || e.Property == TextView.NonPrintableCharacterBrushProperty)
 			{
 				RecreateCachedElements();
 				InvalidateWideSpaceWidthAndDefaultLineHeight();

src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Rendering/TextViewCachedElements.cs

@@ -12,28 +12,28 @@ namespace ICSharpCode.AvalonEdit.Rendering
 	sealed class TextViewCachedElements : IDisposable
 	{
 		TextFormatter formatter;
-		Dictionary<string, TextLine> simpleLightGrayTexts;
+		Dictionary<string, TextLine> nonPrintableCharacterTexts;
 		
-		public TextLine GetSimpleLightGrayText(string text, ITextRunConstructionContext context)
+		public TextLine GetTextForNonPrintableCharacter(string text, ITextRunConstructionContext context)
 		{
-			if (simpleLightGrayTexts == null)
-				simpleLightGrayTexts = new Dictionary<string, TextLine>();
+			if (nonPrintableCharacterTexts == null)
+				nonPrintableCharacterTexts = new Dictionary<string, TextLine>();
 			TextLine textLine;
-			if (!simpleLightGrayTexts.TryGetValue(text, out textLine)) {
+			if (!nonPrintableCharacterTexts.TryGetValue(text, out textLine)) {
 				var p = new VisualLineElementTextRunProperties(context.GlobalTextRunProperties);
-				p.SetForegroundBrush(Brushes.LightGray);
+				p.SetForegroundBrush(context.TextView.NonPrintableCharacterBrush);
 				if (formatter == null)
 					formatter = TextFormatterFactory.Create(context.TextView);
 				textLine = FormattedTextElement.PrepareText(formatter, text, p);
-				simpleLightGrayTexts[text] = textLine;
+				nonPrintableCharacterTexts[text] = textLine;
 			}
 			return textLine;
 		}
 		
 		public void Dispose()
 		{
-			if (simpleLightGrayTexts != null) {
-				foreach (TextLine line in simpleLightGrayTexts.Values)
+			if (nonPrintableCharacterTexts != null) {
+				foreach (TextLine line in nonPrintableCharacterTexts.Values)
 					line.Dispose();
 			}
 			if (formatter != null)