Theme Editor: use real colors as background of color strings

flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatSyntaxTextArea.java

@@ -16,7 +16,13 @@
 
 package com.formdev.flatlaf.themeeditor;
 
+import java.awt.Color;
+import java.util.HashMap;
+import java.util.Map;
+import javax.swing.text.BadLocationException;
 import org.fife.ui.rsyntaxtextarea.TextEditorPane;
+import org.fife.ui.rsyntaxtextarea.Token;
+import com.formdev.flatlaf.UIDefaultsLoaderAccessor;
 
 /**
  * A text area that supports editing FlatLaf themes.
@@ -26,6 +32,76 @@ import org.fife.ui.rsyntaxtextarea.TextEditorPane;
 class FlatSyntaxTextArea
 	extends TextEditorPane
 {
+	private boolean useColorOfColorTokens;
+
+	private final Map<String, Color> parsedColorsMap = new HashMap<>();
+
 	FlatSyntaxTextArea() {
 	}
+
+	boolean isUseColorOfColorTokens() {
+		return useColorOfColorTokens;
+	}
+
+	void setUseColorOfColorTokens( boolean useColorOfColorTokens ) {
+		this.useColorOfColorTokens = useColorOfColorTokens;
+		setHighlightCurrentLine( !useColorOfColorTokens );
+	}
+
+	@Override
+	public Color getBackgroundForToken( Token t ) {
+		if( useColorOfColorTokens && t.getType() == FlatThemeTokenMaker.TOKEN_COLOR ) {
+			Color color = parseColor( t );
+			if( color != null )
+				return color;
+		}
+
+		return super.getBackgroundForToken( t );
+	}
+
+	@Override
+	public Color getForegroundForToken( Token t ) {
+		if( useColorOfColorTokens && t.getType() == FlatThemeTokenMaker.TOKEN_COLOR && !isCurrentLineHighlighted( t.getOffset() )) {
+			Color color = parseColor( t );
+			if( color != null ) {
+				return (colorLuminance( color ) > 164 || color.getAlpha() < 96)
+					? Color.black
+					: Color.white;
+			}
+		}
+
+		return super.getForegroundForToken( t );
+	}
+
+	private Color parseColor( Token token ) {
+		return parsedColorsMap.computeIfAbsent( token.getLexeme(), s -> {
+			try {
+				return new Color( UIDefaultsLoaderAccessor.parseColorRGBA( s ), true );
+			} catch( IllegalArgumentException ex ) {
+				return null;
+			}
+		} );
+
+	}
+
+	private int colorLuminance( Color c ) {
+		int red = c.getRed();
+		int green = c.getGreen();
+		int blue = c.getBlue();
+
+		int min = Math.min( red, Math.min( green, blue ) );
+		int max = Math.max( red, Math.max( green, blue ) );
+
+		return (max + min) / 2;
+	}
+
+	private boolean isCurrentLineHighlighted( int offset ) {
+		try {
+			return getHighlightCurrentLine() &&
+				getSelectionStart() == getSelectionEnd() &&
+				getLineOfOffset( offset ) == getLineOfOffset( getSelectionStart() );
+		} catch( BadLocationException ex ) {
+			return false;
+		}
+	}
 }

flatlaf-theme-editor/src/main/java/com/formdev/flatlaf/themeeditor/FlatThemeEditorPane.java

@@ -55,6 +55,7 @@ class FlatThemeEditorPane
 		textArea.setSyntaxEditingStyle( FLATLAF_STYLE );
 		textArea.setMarkOccurrences( true );
 		textArea.addParser( new FlatThemeParser() );
+		textArea.setUseColorOfColorTokens( true );
 
 		// theme
 		try {