Button: hover and pressed background colors are now derived from actual button background color (issue #21)

CHANGELOG.md

@@ -10,6 +10,8 @@ FlatLaf Change Log
   `JPasswordField`, `JScrollPane` and `JTextField` are non-opaque if they have
   an outside focus border (e.g. IntelliJ and Darcula themes). (issues #20 and
   #17)
+- Button: Hover and pressed background colors are now derived from actual button
+  background color. (issue #21)
 
 
 ## 0.16

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

@@ -36,6 +36,8 @@ import javax.swing.plaf.DimensionUIResource;
 import javax.swing.plaf.InsetsUIResource;
 import com.formdev.flatlaf.ui.FlatEmptyBorder;
 import com.formdev.flatlaf.ui.FlatLineBorder;
+import com.formdev.flatlaf.util.ColorFunctions;
+import com.formdev.flatlaf.util.DerivedColor;
 import com.formdev.flatlaf.util.ScaledNumber;
 
 /**
@@ -101,7 +103,11 @@ class UIDefaultsLoader
 					continue;
 
 				String value = resolveValue( properties, (String) e.getValue() );
+				try {
 					globals.put( key.substring( GLOBAL_PREFIX.length() ), parseValue( key, value, resolver ) );
+				} catch( RuntimeException ex ) {
+					logParseError( key, value, ex );
+				}
 			}
 
 			// override UI defaults with globals
@@ -122,13 +128,22 @@ class UIDefaultsLoader
 					continue;
 
 				String value = resolveValue( properties, (String) e.getValue() );
+				try {
 					defaults.put( key, parseValue( key, value, resolver ) );
+				} catch( RuntimeException ex ) {
+					logParseError( key, value, ex );
+				}
 			}
 		} catch( IOException ex ) {
 			ex.printStackTrace();
 		}
 	}
 
+	private static void logParseError( String key, String value, RuntimeException ex ) {
+		System.err.println( "Failed to parse: '" + key + '=' + value + '\'' );
+		System.err.println( "    " + ex.getMessage() );
+	}
+
 	private static String resolveValue( Properties properties, String value ) {
 		if( !value.startsWith( VARIABLE_PREFIX ) )
 			return value;
@@ -147,8 +162,7 @@ class UIDefaultsLoader
 			if( optional )
 				return "null";
 
-			System.err.println( "variable or reference '" + value + "' not found" );
+			throw new IllegalArgumentException( "variable or reference '" + value + "' not found" );
-			throw new IllegalArgumentException( value );
 		}
 
 		return resolveValue( properties, newValue );
@@ -264,8 +278,7 @@ class UIDefaultsLoader
 				Integer.parseInt( numbers.get( 2 ) ),
 				Integer.parseInt( numbers.get( 3 ) ) );
 		} catch( NumberFormatException ex ) {
-			System.err.println( "invalid insets '" + value + "'" );
+			throw new IllegalArgumentException( "invalid insets '" + value + "'" );
-			throw ex;
 		}
 	}
 
@@ -276,12 +289,14 @@ class UIDefaultsLoader
 				Integer.parseInt( numbers.get( 0 ) ),
 				Integer.parseInt( numbers.get( 1 ) ) );
 		} catch( NumberFormatException ex ) {
-			System.err.println( "invalid size '" + value + "'" );
+			throw new IllegalArgumentException( "invalid size '" + value + "'" );
-			throw ex;
 		}
 	}
 
 	private static ColorUIResource parseColor( String value, boolean reportError ) {
+		if( value.endsWith( ")" ) )
+			return parseColorFunctions( value, reportError );
+
 		try {
 			int rgb = Integer.parseInt( value, 16 );
 			if( value.length() == 6 )
@@ -292,23 +307,78 @@ class UIDefaultsLoader
 			if( reportError )
 				throw new NumberFormatException( value );
 		} catch( NumberFormatException ex ) {
-			if( reportError ) {
+			if( reportError )
-				System.err.println( "invalid color '" + value + "'" );
+				throw new IllegalArgumentException( "invalid color '" + value + "'" );
-				throw ex;
+
-			}
 			// not a color --> ignore
 		}
 		return null;
 	}
 
+	private static ColorUIResource parseColorFunctions( String value, boolean reportError ) {
+		int paramsStart = value.indexOf( '(' );
+		if( paramsStart < 0 ) {
+			if( reportError )
+				throw new IllegalArgumentException( "missing opening parenthesis in function '" + value + "'" );
+			return null;
+		}
+
+		String function = value.substring( 0, paramsStart ).trim();
+		List<String> params = split( value.substring( paramsStart + 1, value.length() - 1 ), ',' );
+		if( params.isEmpty() )
+			throw new IllegalArgumentException( "missing parameters in function '" + value + "'" );
+
+		switch( function ) {
+			case "lighten":		return parseColorLightenOrDarken( true, params, reportError );
+			case "darken":		return parseColorLightenOrDarken( false, params, reportError );
+		}
+
+		throw new IllegalArgumentException( "unknown color function '" + value + "'" );
+	}
+
+	/**
+	 * Syntax: lighten(amount[,options]) or darken(amount[,options])
+	 *   - amount: percentage 0-100%
+	 *   - options: [relative] [autoInverse]
+	 */
+	private static ColorUIResource parseColorLightenOrDarken( boolean lighten, List<String> params, boolean reportError ) {
+		int amount = parsePercentage( params.get( 0 ) );
+		boolean relative = false;
+		boolean autoInverse = false;
+
+		if( params.size() >= 2 ) {
+			String options = params.get( 1 );
+			relative = options.contains( "relative" );
+			autoInverse = options.contains( "autoInverse" );
+		}
+
+		return new DerivedColor( lighten
+			? new ColorFunctions.Lighten( amount, relative, autoInverse )
+			: new ColorFunctions.Darken( amount, relative, autoInverse ) );
+	}
+
+	private static int parsePercentage( String value ) {
+		if( !value.endsWith( "%" ) )
+			throw new NumberFormatException( "invalid percentage '" + value + "'" );
+
+		int val;
+		try {
+			val = Integer.parseInt( value.substring( 0, value.length() - 1 ) );
+		} catch( NumberFormatException ex ) {
+			throw new NumberFormatException( "invalid percentage '" + value + "'" );
+		}
+
+		if( val < 0 || val > 100 )
+			throw new IllegalArgumentException( "percentage out of range (0-100%) '" + value + "'" );
+		return val;
+	}
+
 	private static Integer parseInteger( String value, boolean reportError ) {
 		try {
 			return Integer.parseInt( value );
 		} catch( NumberFormatException ex ) {
-			if( reportError ) {
+			if( reportError )
-				System.err.println( "invalid integer '" + value + "'" );
+				throw new NumberFormatException( "invalid integer '" + value + "'" );
-				throw ex;
-			}
 		}
 		return null;
 	}
@@ -317,8 +387,7 @@ class UIDefaultsLoader
 		try {
 			return new ScaledNumber( Integer.parseInt( value ) );
 		} catch( NumberFormatException ex ) {
-			System.err.println( "invalid integer '" + value + "'" );
+			throw new NumberFormatException( "invalid integer '" + value + "'" );
-			throw ex;
 		}
 	}
 

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatCheckBoxIcon.java

@@ -109,12 +109,13 @@ public class FlatCheckBoxIcon
 		paintBorder( g2 );
 
 		// paint background
-		g2.setColor( FlatButtonUI.buttonStateColor( c,
+		FlatUIUtils.setColor( g2, FlatButtonUI.buttonStateColor( c,
 			selected ? selectedBackground : background,
 			disabledBackground,
 			focusedBackground,
 			selected && selectedHoverBackground != null ? selectedHoverBackground : hoverBackground,
-			selected && selectedPressedBackground != null ? selectedPressedBackground : pressedBackground ) );
+			selected && selectedPressedBackground != null ? selectedPressedBackground : pressedBackground ),
+			background );
 		paintBackground( g2 );
 
 		// paint checkmark

flatlaf-core/src/main/java/com/formdev/flatlaf/icons/FlatHelpButtonIcon.java

@@ -24,6 +24,7 @@ import java.awt.geom.Ellipse2D;
 import java.awt.geom.Path2D;
 import javax.swing.UIManager;
 import com.formdev.flatlaf.ui.FlatButtonUI;
+import com.formdev.flatlaf.ui.FlatUIUtils;
 
 /**
  * Help button icon for {@link javax.swing.JButton}.
@@ -99,12 +100,12 @@ public class FlatHelpButtonIcon
 		g2.fill( new Ellipse2D.Float( focusWidth + 0.5f, focusWidth + 0.5f, 21, 21 ) );
 
 		// paint background
-		g2.setColor( FlatButtonUI.buttonStateColor( c,
+		FlatUIUtils.setColor( g2, FlatButtonUI.buttonStateColor( c,
 			background,
 			disabledBackground,
 			focusedBackground,
 			hoverBackground,
-			pressedBackground ) );
+			pressedBackground ), background );
 		g2.fill( new Ellipse2D.Float( focusWidth + 1.5f, focusWidth + 1.5f, 19, 19 ) );
 
 		// paint question mark

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

@@ -190,7 +190,7 @@ public class FlatButtonUI
 					float focusWidth = (border instanceof FlatBorder) ? scale( (float) this.focusWidth ) : 0;
 					float arc = (border instanceof FlatButtonBorder || isToolBarButton( c )) ? scale( (float) this.arc ) : 0;
 
-					g2.setColor( background );
+					FlatUIUtils.setColor( g2, background, isDefaultButton(c) ? defaultBackground : c.getBackground() );
 					FlatUIUtils.fillRoundRectangle( g2, 0, 0, c.getWidth(), c.getHeight(), focusWidth, arc );
 				} finally {
 					g2.dispose();

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatUIUtils.java

@@ -38,6 +38,7 @@ import javax.swing.JComponent;
 import javax.swing.LookAndFeel;
 import javax.swing.UIManager;
 import javax.swing.plaf.ColorUIResource;
+import com.formdev.flatlaf.util.DerivedColor;
 import com.formdev.flatlaf.util.JavaCompatibility;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -104,6 +105,12 @@ public class FlatUIUtils
 			MAC_USE_QUARTZ ? RenderingHints.VALUE_STROKE_PURE : RenderingHints.VALUE_STROKE_NORMALIZE );
 	}
 
+	public static void setColor( Graphics g, Color color, Color baseColor ) {
+		if( color instanceof DerivedColor )
+			color = ((DerivedColor)color).derive( baseColor );
+		g.setColor( color );
+	}
+
 	/**
 	 * Draws a round rectangle.
 	 */

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

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2019 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.util;
+
+import java.awt.Color;
+
+/**
+ * Functions that modify colors.
+ *
+ * @author Karl Tauber
+ */
+public class ColorFunctions
+{
+	public static Color applyFunctions( Color color, ColorFunction[] functions ) {
+		float[] hsl = HSLColor.fromRGB( color );
+		float alpha = color.getAlpha() / 255f;
+
+		for( ColorFunction function : functions )
+			function.apply( hsl );
+
+		return HSLColor.toRGB( hsl, alpha );
+	}
+
+	private static float clamp( float value ) {
+		return (value < 0)
+			? 0
+			: ((value > 100)
+				? 100
+				: value);
+	}
+
+	//---- interface ColorFunction --------------------------------------------
+
+	public interface ColorFunction {
+		void apply( float[] hsl );
+	}
+
+	//---- class Lighten ------------------------------------------------------
+
+	/**
+	 * Increase the lightness of a color in the HSL color space by an absolute
+	 * or relative amount.
+	 */
+	public static class Lighten
+		implements ColorFunction
+	{
+		private final float amount;
+		private final boolean relative;
+		private final boolean autoInverse;
+
+		public Lighten( float amount, boolean relative, boolean autoInverse ) {
+			this.amount = amount;
+			this.relative = relative;
+			this.autoInverse = autoInverse;
+		}
+
+		@Override
+		public void apply( float[] hsl ) {
+			float amount2 = autoInverse && shouldInverse( hsl ) ? -amount : amount;
+			hsl[2] = clamp( relative
+				? (hsl[2] * ((100 + amount2) / 100))
+				: (hsl[2] + amount2) );
+		}
+
+		protected boolean shouldInverse( float[] hsl ) {
+			return hsl[2] >= 50;
+		}
+	}
+
+	//---- class Darken -------------------------------------------------------
+
+	/**
+	 * Decrease the lightness of a color in the HSL color space by an absolute
+	 * or relative amount.
+	 */
+	public static class Darken
+		extends Lighten
+	{
+		public Darken( float amount, boolean relative, boolean autoInverse ) {
+			super( -amount, relative, autoInverse );
+		}
+
+		@Override
+		protected boolean shouldInverse( float[] hsl ) {
+			return hsl[2] < 50;
+		}
+	}
+}

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

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2019 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.util;
+
+import java.awt.Color;
+import javax.swing.plaf.ColorUIResource;
+import com.formdev.flatlaf.util.ColorFunctions.ColorFunction;
+
+/**
+ * A (red) color that acts as a placeholder in UI defaults.
+ * The actual color is derived from another color,
+ * which is modified by the given color functions.
+ *
+ * @author Karl Tauber
+ */
+public class DerivedColor
+	extends ColorUIResource
+{
+	private final ColorFunction[] functions;
+
+	public DerivedColor( ColorFunction... functions ) {
+		super( Color.red );
+		this.functions = functions;
+	}
+
+	public Color derive( Color baseColor ) {
+		return ColorFunctions.applyFunctions( baseColor, functions );
+	}
+}

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

@@ -0,0 +1,432 @@
+/*
+ * From http://tips4java.wordpress.com/2009/07/05/hsl-color/
+ *
+ * License note on http://tips4java.wordpress.com/about/
+ *   "You are free to use and/or modify any or all code posted on the
+ *    Java Tips Weblog without restriction. A credit in the code comments
+ *    would be nice, but not in any way mandatory."
+ */
+
+package com.formdev.flatlaf.util;
+
+import java.awt.Color;
+
+/**
+ *  The HSLColor class provides methods to manipulate HSL (Hue, Saturation
+ *  Luminance) values to create a corresponding Color object using the RGB
+ *  ColorSpace.
+ *
+ *  The HUE is the color, the Saturation is the purity of the color (with
+ *  respect to grey) and Luminance is the brightness of the color (with respect
+ *  to black and white)
+ *
+ *  The Hue is specified as an angel between 0 - 360 degrees where red is 0,
+ *  green is 120 and blue is 240. In between you have the colors of the rainbow.
+ *  Saturation is specified as a percentage between 0 - 100 where 100 is fully
+ *  saturated and 0 approaches gray. Luminance is specified as a percentage
+ *  between 0 - 100 where 0 is black and 100 is white.
+ *
+ *  In particular the HSL color space makes it easier change the Tone or Shade
+ *  of a color by adjusting the luminance value.
+ */
+public class HSLColor
+{
+	private final Color rgb;
+	private final float[] hsl;
+	private final float alpha;
+
+	/**
+	 *  Create a HSLColor object using an RGB Color object.
+	 *
+	 *  @param rgb the RGB Color object
+	 */
+	public HSLColor(Color rgb)
+	{
+		this.rgb = rgb;
+		hsl = fromRGB( rgb );
+		alpha = rgb.getAlpha() / 255.0f;
+	}
+
+	/**
+	 *  Create a HSLColor object using individual HSL values and a default
+	 * alpha value of 1.0.
+	 *
+	 *  @param h is the Hue value in degrees between 0 - 360
+	 *  @param s is the Saturation percentage between 0 - 100
+	 *  @param l is the Lumanance percentage between 0 - 100
+	 */
+	public HSLColor(float h, float s, float l)
+	{
+		this(h, s, l, 1.0f);
+	}
+
+	/**
+	 *  Create a HSLColor object using individual HSL values.
+	 *
+	 *  @param h     the Hue value in degrees between 0 - 360
+	 *  @param s     the Saturation percentage between 0 - 100
+	 *  @param l     the Lumanance percentage between 0 - 100
+	 *  @param alpha the alpha value between 0 - 1
+	 */
+	public HSLColor(float h, float s, float l, float alpha)
+	{
+		hsl = new float[] {h, s, l};
+		this.alpha = alpha;
+		rgb = toRGB(hsl, alpha);
+	}
+
+	/**
+	 *  Create a HSLColor object using an an array containing the
+	 *  individual HSL values and with a default alpha value of 1.
+	 *
+	 *  @param hsl  array containing HSL values
+	 */
+	public HSLColor(float[] hsl)
+	{
+		this(hsl, 1.0f);
+	}
+
+	/**
+	 *  Create a HSLColor object using an an array containing the
+	 *  individual HSL values.
+	 *
+	 *  @param hsl  array containing HSL values
+	 *  @param alpha the alpha value between 0 - 1
+	 */
+	public HSLColor(float[] hsl, float alpha)
+	{
+		this.hsl = hsl;
+		this.alpha = alpha;
+		rgb = toRGB(hsl, alpha);
+	}
+
+	/**
+	 *  Create a RGB Color object based on this HSLColor with a different
+	 *  Hue value. The degrees specified is an absolute value.
+	 *
+	 *  @param degrees - the Hue value between 0 - 360
+	 *  @return the RGB Color object
+	 */
+	public Color adjustHue(float degrees)
+	{
+		return toRGB(degrees, hsl[1], hsl[2], alpha);
+	}
+
+	/**
+	 *  Create a RGB Color object based on this HSLColor with a different
+	 *  Luminance value. The percent specified is an absolute value.
+	 *
+	 *  @param percent - the Luminance value between 0 - 100
+	 *  @return the RGB Color object
+	 */
+	public Color adjustLuminance(float percent)
+	{
+		return toRGB(hsl[0], hsl[1], percent, alpha);
+	}
+
+	/**
+	 *  Create a RGB Color object based on this HSLColor with a different
+	 *  Saturation value. The percent specified is an absolute value.
+	 *
+	 *  @param percent - the Saturation value between 0 - 100
+	 *  @return the RGB Color object
+	 */
+	public Color adjustSaturation(float percent)
+	{
+		return toRGB(hsl[0], percent, hsl[2], alpha);
+	}
+
+	/**
+	 *  Create a RGB Color object based on this HSLColor with a different
+	 *  Shade. Changing the shade will return a darker color. The percent
+	 *  specified is a relative value.
+	 *
+	 *  @param percent - the value between 0 - 100
+	 *  @return the RGB Color object
+	 */
+	public Color adjustShade(float percent)
+	{
+		float multiplier = (100.0f - percent) / 100.0f;
+		float l = Math.max(0.0f, hsl[2] * multiplier);
+
+		return toRGB(hsl[0], hsl[1], l, alpha);
+	}
+
+	/**
+	 *  Create a RGB Color object based on this HSLColor with a different
+	 *  Tone. Changing the tone will return a lighter color. The percent
+	 *  specified is a relative value.
+	 *
+	 *  @param percent - the value between 0 - 100
+	 *  @return the RGB Color object
+	 */
+	public Color adjustTone(float percent)
+	{
+		float multiplier = (100.0f + percent) / 100.0f;
+		float l = Math.min(100.0f, hsl[2] * multiplier);
+
+		return toRGB(hsl[0], hsl[1], l, alpha);
+	}
+
+	/**
+	 *  Get the Alpha value.
+	 *
+	 *  @return the Alpha value.
+	 */
+	public float getAlpha()
+	{
+		return alpha;
+	}
+
+	/**
+	 *  Create a RGB Color object that is the complementary color of this
+	 *  HSLColor. This is a convenience method. The complementary color is
+	 *  determined by adding 180 degrees to the Hue value.
+	 *  @return the RGB Color object
+	 */
+	public Color getComplementary()
+	{
+		float hue = (hsl[0] + 180.0f) % 360.0f;
+		return toRGB(hue, hsl[1], hsl[2]);
+	}
+
+	/**
+	 *  Get the Hue value.
+	 *
+	 *  @return the Hue value.
+	 */
+	public float getHue()
+	{
+		return hsl[0];
+	}
+
+	/**
+	 *  Get the HSL values.
+	 *
+	 *  @return the HSL values.
+	 */
+	public float[] getHSL()
+	{
+		return hsl;
+	}
+
+	/**
+	 *  Get the Luminance value.
+	 *
+	 *  @return the Luminance value.
+	 */
+	public float getLuminance()
+	{
+		return hsl[2];
+	}
+
+	/**
+	 *  Get the RGB Color object represented by this HDLColor.
+	 *
+	 *  @return the RGB Color object.
+	 */
+	public Color getRGB()
+	{
+		return rgb;
+	}
+
+	/**
+	 *  Get the Saturation value.
+	 *
+	 *  @return the Saturation value.
+	 */
+	public float getSaturation()
+	{
+		return hsl[1];
+	}
+
+	@Override
+	public String toString()
+	{
+		String toString =
+			"HSLColor[h=" + hsl[0] +
+			",s=" + hsl[1] +
+			",l=" + hsl[2] +
+			",alpha=" + alpha + "]";
+
+		return toString;
+	}
+
+	/**
+	 *  Convert a RGB Color to it corresponding HSL values.
+	 *
+	 *  @return an array containing the 3 HSL values.
+	 */
+	public static float[] fromRGB(Color color)
+	{
+		//  Get RGB values in the range 0 - 1
+
+		float[] rgb = color.getRGBColorComponents( null );
+		float r = rgb[0];
+		float g = rgb[1];
+		float b = rgb[2];
+
+		//	Minimum and Maximum RGB values are used in the HSL calculations
+
+		float min = Math.min(r, Math.min(g, b));
+		float max = Math.max(r, Math.max(g, b));
+
+		//  Calculate the Hue
+
+		float h = 0;
+
+		if (max == min)
+			h = 0;
+		else if (max == r)
+			h = ((60 * (g - b) / (max - min)) + 360) % 360;
+		else if (max == g)
+			h = (60 * (b - r) / (max - min)) + 120;
+		else if (max == b)
+			h = (60 * (r - g) / (max - min)) + 240;
+
+		//  Calculate the Luminance
+
+		float l = (max + min) / 2;
+//		System.out.println(max + " : " + min + " : " + l);
+
+		//  Calculate the Saturation
+
+		float s = 0;
+
+		if (max == min)
+			s = 0;
+		else if (l <= .5f)
+			s = (max - min) / (max + min);
+		else
+			s = (max - min) / (2 - max - min);
+
+//		System.out.println(new HSLColor( new float[] {h, s * 100, l * 100} ));
+		return new float[] {h, s * 100, l * 100};
+	}
+
+	/**
+	 *  Convert HSL values to a RGB Color with a default alpha value of 1.
+	 *  H (Hue) is specified as degrees in the range 0 - 360.
+	 *  S (Saturation) is specified as a percentage in the range 1 - 100.
+	 *  L (Lumanance) is specified as a percentage in the range 1 - 100.
+	 *
+	 *  @param hsl an array containing the 3 HSL values
+	 *
+	 *  @returns the RGB Color object
+	 */
+	public static Color toRGB(float[] hsl)
+	{
+		return toRGB(hsl, 1.0f);
+	}
+
+	/**
+	 *  Convert HSL values to a RGB Color.
+	 *  H (Hue) is specified as degrees in the range 0 - 360.
+	 *  S (Saturation) is specified as a percentage in the range 1 - 100.
+	 *  L (Lumanance) is specified as a percentage in the range 1 - 100.
+	 *
+	 *  @param hsl    an array containing the 3 HSL values
+	 *  @param alpha  the alpha value between 0 - 1
+	 *
+	 *  @returns the RGB Color object
+	 */
+	public static Color toRGB(float[] hsl, float alpha)
+	{
+		return toRGB(hsl[0], hsl[1], hsl[2], alpha);
+	}
+
+	/**
+	 *  Convert HSL values to a RGB Color with a default alpha value of 1.
+	 *
+	 *  @param h Hue is specified as degrees in the range 0 - 360.
+	 *  @param s Saturation is specified as a percentage in the range 1 - 100.
+	 *  @param l Lumanance is specified as a percentage in the range 1 - 100.
+	 *
+	 *  @returns the RGB Color object
+	 */
+	public static Color toRGB(float h, float s, float l)
+	{
+		return toRGB(h, s, l, 1.0f);
+	}
+
+	/**
+	 *  Convert HSL values to a RGB Color.
+	 *
+	 *  @param h Hue is specified as degrees in the range 0 - 360.
+	 *  @param s Saturation is specified as a percentage in the range 1 - 100.
+	 *  @param l Lumanance is specified as a percentage in the range 1 - 100.
+	 *  @param alpha  the alpha value between 0 - 1
+	 *
+	 *  @returns the RGB Color object
+	 */
+	public static Color toRGB(float h, float s, float l, float alpha)
+	{
+		if (s <0.0f || s > 100.0f)
+		{
+			String message = "Color parameter outside of expected range - Saturation";
+			throw new IllegalArgumentException( message );
+		}
+
+		if (l <0.0f || l > 100.0f)
+		{
+			String message = "Color parameter outside of expected range - Luminance";
+			throw new IllegalArgumentException( message );
+		}
+
+		if (alpha <0.0f || alpha > 1.0f)
+		{
+			String message = "Color parameter outside of expected range - Alpha";
+			throw new IllegalArgumentException( message );
+		}
+
+		//  Formula needs all values between 0 - 1.
+
+		h = h % 360.0f;
+		h /= 360f;
+		s /= 100f;
+		l /= 100f;
+
+		float q = 0;
+
+		if (l < 0.5)
+			q = l * (1 + s);
+		else
+			q = (l + s) - (s * l);
+
+		float p = 2 * l - q;
+
+		float r = Math.max(0, HueToRGB(p, q, h + (1.0f / 3.0f)));
+		float g = Math.max(0, HueToRGB(p, q, h));
+		float b = Math.max(0, HueToRGB(p, q, h - (1.0f / 3.0f)));
+
+		r = Math.min(r, 1.0f);
+		g = Math.min(g, 1.0f);
+		b = Math.min(b, 1.0f);
+
+		return new Color(r, g, b, alpha);
+	}
+
+	private static float HueToRGB(float p, float q, float h)
+	{
+		if (h < 0) h += 1;
+
+		if (h > 1 ) h -= 1;
+
+		if (6 * h < 1)
+		{
+			return p + ((q - p) * 6 * h);
+		}
+
+		if (2 * h < 1 )
+		{
+			return  q;
+		}
+
+		if (3 * h < 2)
+		{
+			return p + ( (q - p) * 6 * ((2.0f / 3.0f) - h) );
+		}
+
+   		return p;
+	}
+}

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

@@ -31,6 +31,10 @@
 @cellFocusColor=000000
 @icon=adadad
 
+# Button
+@buttonHoverBackground=lighten(3%,autoInverse)
+@buttonPressedBackground=lighten(6%,autoInverse)
+
 
 #---- globals ----
 
@@ -63,8 +67,8 @@ window=@background
 #---- Button ----
 
 Button.background=4c5052
-Button.hoverBackground=525658
+Button.hoverBackground=@buttonHoverBackground
-Button.pressedBackground=5c6164
+Button.pressedBackground=@buttonPressedBackground
 
 Button.borderColor=5e6060
 Button.disabledBorderColor=5e6060
@@ -73,8 +77,8 @@ Button.hoverBorderColor=@@Button.focusedBorderColor
 
 Button.default.background=365880
 Button.default.foreground=bbbbbb
-Button.default.hoverBackground=3d6185
+Button.default.hoverBackground=@buttonHoverBackground
-Button.default.pressedBackground=43688c
+Button.default.pressedBackground=@buttonPressedBackground
 Button.default.borderColor=4c708c
 Button.default.hoverBorderColor=537699
 Button.default.focusedBorderColor=537699
@@ -95,8 +99,8 @@ CheckBox.icon.hoverBorderColor=@@CheckBox.icon.focusedBorderColor
 CheckBox.icon.selectedFocusedBorderColor=466D94
 CheckBox.icon.background=43494A
 CheckBox.icon.disabledBackground=@background
-CheckBox.icon.hoverBackground=4c5052
+CheckBox.icon.hoverBackground=@buttonHoverBackground
-CheckBox.icon.pressedBackground=@@Button.pressedBackground
+CheckBox.icon.pressedBackground=@buttonPressedBackground
 CheckBox.icon.selectedBackground=43494A
 CheckBox.icon.checkmarkColor=A7A7A7
 CheckBox.icon.disabledCheckmarkColor=606060

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

@@ -31,6 +31,10 @@
 @cellFocusColor=000000
 @icon=afafaf
 
+# Button
+@buttonHoverBackground=darken(3%,autoInverse)
+@buttonPressedBackground=darken(10%,autoInverse)
+
 
 #---- globals ----
 
@@ -64,8 +68,8 @@ window=@background
 
 Button.background=ffffff
 Button.focusedBackground=e3f1fa
-Button.hoverBackground=f8f8f8
+Button.hoverBackground=@buttonHoverBackground
-Button.pressedBackground=dfdfdf
+Button.pressedBackground=@buttonPressedBackground
 
 Button.borderColor=bfbfbf
 Button.disabledBorderColor=cfcfcf
@@ -75,8 +79,8 @@ Button.hoverBorderColor=@@Button.focusedBorderColor
 Button.default.background=@@Button.background
 Button.default.foreground=@foreground
 Button.default.focusedBackground=@@Button.focusedBackground
-Button.default.hoverBackground=@@Button.hoverBackground
+Button.default.hoverBackground=@buttonHoverBackground
-Button.default.pressedBackground=@@Button.pressedBackground
+Button.default.pressedBackground=@buttonPressedBackground
 Button.default.borderColor=4D89C9
 Button.default.hoverBorderColor=@@Button.hoverBorderColor
 Button.default.focusedBorderColor=@@Button.focusedBorderColor
@@ -97,8 +101,8 @@ CheckBox.icon.hoverBorderColor=@@CheckBox.icon.focusedBorderColor
 CheckBox.icon.background=FFFFFF
 CheckBox.icon.disabledBackground=@background
 CheckBox.icon.focusedBackground=@@Button.focusedBackground
-CheckBox.icon.hoverBackground=@@Button.hoverBackground
+CheckBox.icon.hoverBackground=@buttonHoverBackground
-CheckBox.icon.pressedBackground=@@Button.pressedBackground
+CheckBox.icon.pressedBackground=@buttonPressedBackground
 CheckBox.icon.selectedBackground=FFFFFF
 CheckBox.icon.checkmarkColor=4D89C9
 CheckBox.icon.disabledCheckmarkColor=ABABAB