UIDefaultsLoader: added fadein(), fadeout(), fade() and spin() color functions (inspired by Less CSS)

flatlaf-core/src/main/java/com/formdev/flatlaf/UIDefaultsLoader.java

@@ -586,13 +586,17 @@ class UIDefaultsLoader
 			case "darken":		return parseColorHSLIncreaseDecrease( 2, false, params, resolver, reportError );
 			case "saturate":	return parseColorHSLIncreaseDecrease( 1, true, params, resolver, reportError );
 			case "desaturate":	return parseColorHSLIncreaseDecrease( 1, false, params, resolver, reportError );
+			case "fadein":		return parseColorHSLIncreaseDecrease( 3, true, params, resolver, reportError );
+			case "fadeout":		return parseColorHSLIncreaseDecrease( 3, false, params, resolver, reportError );
+			case "fade":		return parseColorFade( params, resolver, reportError );
+			case "spin":		return parseColorSpin( params, resolver, reportError );
 		}
 
 		throw new IllegalArgumentException( "unknown color function '" + value + "'" );
 	}
 
 	/**
-	 * Syntax: rgb(red,green,blue) or rgba(red,green,blue,alpha) or rgba(color,alpha)
+	 * Syntax: rgb(red,green,blue) or rgba(red,green,blue,alpha)
 	 *   - red:   an integer 0-255 or a percentage 0-100%
 	 *   - green: an integer 0-255 or a percentage 0-100%
 	 *   - blue:  an integer 0-255 or a percentage 0-100%
@@ -603,6 +607,8 @@ class UIDefaultsLoader
 	{
 		if( hasAlpha && params.size() == 2 ) {
 			// syntax rgba(color,alpha), which allows adding alpha to any color
+			// NOTE: this syntax is deprecated
+			//       use fade(color,alpha) instead
 			String colorStr = params.get( 0 );
 			int alpha = parseInteger( params.get( 1 ), 0, 255, true );
 
@@ -639,7 +645,8 @@ class UIDefaultsLoader
 
 	/**
 	 * Syntax: lighten(color,amount[,options]) or darken(color,amount[,options]) or
-	 *         saturate(color,amount[,options]) or desaturate(color,amount[,options])
+	 *         saturate(color,amount[,options]) or desaturate(color,amount[,options]) or
+	 *         fadein(color,amount[,options]) or fadeout(color,amount[,options])
 	 *   - color: a color (e.g. #f00) or a color function
 	 *   - amount: percentage 0-100%
 	 *   - options: [relative] [autoInverse] [noAutoInverse] [lazy] [derived]
@@ -679,6 +686,59 @@ class UIDefaultsLoader
 			};
 		}
 
+		// parse base color, apply function and create derived color
+		return parseFunctionBaseColor( colorStr, function, derived, resolver, reportError );
+	}
+
+	/**
+	 * Syntax: fade(color,amount[,options])
+	 *   - color: a color (e.g. #f00) or a color function
+	 *   - amount: percentage 0-100%
+	 *   - options: [derived]
+	 */
+	private static Object parseColorFade( List<String> params, Function<String, String> resolver, boolean reportError ) {
+		String colorStr = params.get( 0 );
+		int amount = parsePercentage( params.get( 1 ) );
+		boolean derived = false;
+
+		if( params.size() > 2 ) {
+			String options = params.get( 2 );
+			derived = options.contains( "derived" );
+		}
+
+		// create function
+		ColorFunction function = new ColorFunctions.Fade( amount );
+
+		// parse base color, apply function and create derived color
+		return parseFunctionBaseColor( colorStr, function, derived, resolver, reportError );
+	}
+
+	/**
+	 * Syntax: spin(color,angle[,options])
+	 *   - color: a color (e.g. #f00) or a color function
+	 *   - angle: number of degrees to rotate
+	 *   - options: [derived]
+	 */
+	private static Object parseColorSpin( List<String> params, Function<String, String> resolver, boolean reportError ) {
+		String colorStr = params.get( 0 );
+		int amount = parseInteger( params.get( 1 ), true );
+		boolean derived = false;
+
+		if( params.size() > 2 ) {
+			String options = params.get( 2 );
+			derived = options.contains( "derived" );
+		}
+
+		// create function
+		ColorFunction function = new ColorFunctions.HSLIncreaseDecrease( 0, true, amount, false, false );
+
+		// parse base color, apply function and create derived color
+		return parseFunctionBaseColor( colorStr, function, derived, resolver, reportError );
+	}
+
+	private static Object parseFunctionBaseColor( String colorStr, ColorFunction function,
+		boolean derived, Function<String, String> resolver, boolean reportError )
+	{
 		// parse base color
 		String resolvedColorStr = resolver.apply( colorStr );
 		ColorUIResource baseColor = (ColorUIResource) parseColorOrFunction( resolvedColorStr, resolver, reportError );

flatlaf-core/src/main/java/com/formdev/flatlaf/util/ColorFunctions.java

@@ -28,11 +28,12 @@ public class ColorFunctions
 	public static Color applyFunctions( Color color, ColorFunction... functions ) {
 		float[] hsl = HSLColor.fromRGB( color );
 		float alpha = color.getAlpha() / 255f;
+		float[] hsla = { hsl[0], hsl[1], hsl[2], alpha * 100 };
 
 		for( ColorFunction function : functions )
-			function.apply( hsl );
+			function.apply( hsla );
 
-		return HSLColor.toRGB( hsl, alpha );
+		return HSLColor.toRGB( hsla[0], hsla[1], hsla[2], hsla[3] / 100 );
 	}
 
 	public static float clamp( float value ) {
@@ -46,13 +47,13 @@ public class ColorFunctions
 	//---- interface ColorFunction --------------------------------------------
 
 	public interface ColorFunction {
-		void apply( float[] hsl );
+		void apply( float[] hsla );
 	}
 
 	//---- class HSLIncreaseDecrease ------------------------------------------
 
 	/**
-	 * Increase or decrease hue, saturation or luminance of a color in the HSL color space
+	 * Increase or decrease hue, saturation, luminance or alpha of a color in the HSL color space
 	 * by an absolute or relative amount.
 	 */
 	public static class HSLIncreaseDecrease
@@ -75,18 +76,45 @@ public class ColorFunctions
 		}
 
 		@Override
-		public void apply( float[] hsl ) {
+		public void apply( float[] hsla ) {
 			float amount2 = increase ? amount : -amount;
-			amount2 = autoInverse && shouldInverse( hsl ) ? -amount2 : amount2;
+
-			hsl[hslIndex] = clamp( relative
+			if( hslIndex == 0 ) {
-				? (hsl[hslIndex] * ((100 + amount2) / 100))
+				// hue is range 0-360
-				: (hsl[hslIndex] + amount2) );
+				hsla[0] = (hsla[0] + amount2) % 360;
+				return;
 			}
 
-		protected boolean shouldInverse( float[] hsl ) {
+			amount2 = autoInverse && shouldInverse( hsla ) ? -amount2 : amount2;
+			hsla[hslIndex] = clamp( relative
+				? (hsla[hslIndex] * ((100 + amount2) / 100))
+				: (hsla[hslIndex] + amount2) );
+		}
+
+		protected boolean shouldInverse( float[] hsla ) {
 			return increase
-				? hsl[hslIndex] >= 50
+				? hsla[hslIndex] >= 50
-				: hsl[hslIndex] < 50;
+				: hsla[hslIndex] < 50;
+		}
+	}
+
+	//---- class HSLIncreaseDecrease ------------------------------------------
+
+	/**
+	 * Set the alpha of a color.
+	 */
+	public static class Fade
+		implements ColorFunction
+	{
+		public final float amount;
+
+		public Fade( float amount ) {
+			this.amount = amount;
+		}
+
+		@Override
+		public void apply( float[] hsla ) {
+			hsla[3] = clamp( amount );
 		}
 	}
 }

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatDarkLaf.properties

@@ -241,7 +241,7 @@ Slider.trackValueColor=#4A88C7
 Slider.trackColor=#646464
 Slider.thumbColor=$Slider.trackValueColor
 Slider.tickColor=#888
-Slider.focusedColor=rgba($Component.focusColor,80%)
+Slider.focusedColor=fade($Component.focusColor,80%)
 Slider.hoverThumbColor=darken($Slider.thumbColor,10%,derived)
 Slider.pressedThumbColor=darken($Slider.thumbColor,15%,derived)
 Slider.disabledTrackColor=#4c5052

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLaf.properties

@@ -682,7 +682,7 @@ TitlePane.foreground=@foreground
 TitlePane.inactiveForeground=@disabledText
 
 TitlePane.closeHoverBackground=#e81123
-TitlePane.closePressedBackground=rgba($TitlePane.closeHoverBackground,60%)
+TitlePane.closePressedBackground=fade($TitlePane.closeHoverBackground,60%)
 TitlePane.closeHoverForeground=#fff
 TitlePane.closePressedForeground=#fff
 

flatlaf-core/src/main/resources/com/formdev/flatlaf/FlatLightLaf.properties

@@ -253,7 +253,7 @@ Slider.trackValueColor=#1E82E6
 Slider.trackColor=#c4c4c4
 Slider.thumbColor=$Slider.trackValueColor
 Slider.tickColor=#888
-Slider.focusedColor=rgba($Component.focusColor,50%)
+Slider.focusedColor=fade($Component.focusColor,50%)
 Slider.hoverThumbColor=lighten($Slider.thumbColor,10%,derived)
 Slider.pressedThumbColor=lighten($Slider.thumbColor,15%,derived)
 Slider.disabledTrackColor=#c0c0c0

flatlaf-testing/dumps/uidefaults/FlatLightLaf_1.8.0_202.txt

@@ -851,7 +851,7 @@ Slider.disabledTrackColor      #c0c0c0    javax.swing.plaf.ColorUIResource [UI]
 Slider.focus                   #9e9e9e    javax.swing.plaf.ColorUIResource [UI]
 Slider.focusInsets             0,0,0,0    javax.swing.plaf.InsetsUIResource [UI]
 Slider.focusWidth              4
-Slider.focusedColor            #7f97c3f3    javax.swing.plaf.ColorUIResource [UI]
+Slider.focusedColor            #8097c3f3    javax.swing.plaf.ColorUIResource [UI]
 Slider.font                    [active] $defaultFont [UI]
 Slider.foreground              #000000    javax.swing.plaf.ColorUIResource [UI]
 Slider.highlight               #ffffff    javax.swing.plaf.ColorUIResource [UI]

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/uidefaults/UIDefaultsDump.java

@@ -64,6 +64,7 @@ import com.formdev.flatlaf.intellijthemes.FlatAllIJThemes;
 import com.formdev.flatlaf.testing.FlatTestLaf;
 import com.formdev.flatlaf.ui.FlatLineBorder;
 import com.formdev.flatlaf.util.ColorFunctions.ColorFunction;
+import com.formdev.flatlaf.util.ColorFunctions.Fade;
 import com.formdev.flatlaf.util.ColorFunctions.HSLIncreaseDecrease;
 import com.formdev.flatlaf.util.DerivedColor;
 import com.formdev.flatlaf.util.StringUtils;
@@ -399,13 +400,18 @@ public class UIDefaultsDump
 			HSLIncreaseDecrease func = (HSLIncreaseDecrease) function;
 			String name;
 			switch( func.hslIndex ) {
-				case 2: name = func.increase ? "lighten" : "darken"; break;
+				case 0: name = "spin"; break;
 				case 1: name = func.increase ? "saturate" : "desaturate"; break;
+				case 2: name = func.increase ? "lighten" : "darken"; break;
+				case 3: name = func.increase ? "fadein" : "fadeout"; break;
 				default: throw new IllegalArgumentException();
 			}
 			out.printf( "%s(%.0f%%%s%s)", name, func.amount,
 				(func.relative ? " relative" : ""),
 				(func.autoInverse ? " autoInverse" : "") );
+		} else if( function instanceof Fade ) {
+			Fade func = (Fade) function;
+			out.printf( "fade(%.0f%%)", func.amount );
 		} else
 			throw new IllegalArgumentException( "unknown color function: " + function );
 	}

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

@@ -336,8 +336,9 @@ class FlatCompletionProvider
 				"lightness",  "0-100%",
 				"alpha", "0-100%" );
 
+			String colorParamDesc = "a color (e.g. #f00), a reference (e.g. $Other.key) or a color function";
 			String[] hslIncreaseDecreaseParams = {
-				"color", "a color (e.g. #f00), a reference (e.g. $Other.key) or a color function",
+				"color", colorParamDesc,
 				"amount", "0-100%",
 				"options", "(optional) [relative] [autoInverse] [noAutoInverse] [lazy] [derived]"
 			};
@@ -345,6 +346,17 @@ class FlatCompletionProvider
 			addFunction( "darken", hslIncreaseDecreaseParams );
 			addFunction( "saturate", hslIncreaseDecreaseParams );
 			addFunction( "desaturate", hslIncreaseDecreaseParams );
+			addFunction( "fadein", hslIncreaseDecreaseParams );
+			addFunction( "fadeout", hslIncreaseDecreaseParams );
+
+			addFunction( "fade",
+				"color", colorParamDesc,
+				"amount", "0-100%",
+				"options", "(optional) [derived]" );
+			addFunction( "spin",
+				"color", colorParamDesc,
+				"angle", "number of degrees to rotate",
+				"options", "(optional) [derived]" );
 		}
 
 		private void addFunction( String name, String... paramNamesAndDescs ) {

flatlaf-theme-editor/theme-editor-test.properties

@@ -40,3 +40,12 @@ Prop.colorFunc5=lighten(#fe1289,20%)
 Prop.colorFunc6=darken(#fe1289,20%)
 Prop.colorFunc7=lighten($Prop.colorFunc4,20%,relative autoInverse)
 Prop.colorFunc8=lighten(Prop.colorFunc4,20%,lazy)
+Prop.colorFunc9=fadein(#ff000000,30%)
+Prop.colorFunc10=fadeout(#ff0000,40%)
+Prop.colorFunc11=fade(#ff0000,50%)
+
+Prop.colorFunc12=#f00
+Prop.colorFunc13=spin($Prop.colorFunc12,40)
+Prop.colorFunc14=spin($Prop.colorFunc12,-40)
+Prop.colorFunc15=spin($Prop.colorFunc12,400)
+Prop.colorFunc16=spin($Prop.colorFunc12,-400)