support multi-resolution images in disabled icons on Java 9+ (e.g. @2x icons on macOS) (issue #70)

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

@@ -41,6 +41,7 @@ import java.util.Map;
 import java.util.Properties;
 import java.util.ServiceLoader;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import javax.swing.AbstractButton;
@@ -64,6 +65,7 @@ import javax.swing.plaf.basic.BasicLookAndFeel;
 import javax.swing.text.StyleContext;
 import javax.swing.text.html.HTMLEditorKit;
 import com.formdev.flatlaf.util.GrayFilter;
+import com.formdev.flatlaf.util.MultiResolutionImageSupport;
 import com.formdev.flatlaf.util.SystemInfo;
 import com.formdev.flatlaf.util.UIScale;
 
@@ -136,9 +138,14 @@ public abstract class FlatLaf
 					: new GrayFilter(  25, -25, 100 );
 			}
 
+			ImageFilter filter = (ImageFilter) grayFilter;
+			Function<Image, Image> mapper = img -> {
+				ImageProducer producer = new FilteredImageSource( img.getSource(), filter );
+				return Toolkit.getDefaultToolkit().createImage( producer );
+			};
+
 			Image image = ((ImageIcon)icon).getImage();
-			ImageProducer producer = new FilteredImageSource( image.getSource(), (ImageFilter) grayFilter );
-			return new ImageIconUIResource( Toolkit.getDefaultToolkit().createImage( producer ) );
+			return new ImageIconUIResource( MultiResolutionImageSupport.map( image, mapper ) );
 		}
 
 		return null;

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2020 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
+ *
+ *     https://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.Image;
+import java.util.function.Function;
+
+/**
+ * Support for multi-resolution images available since Java 9.
+ *
+ * @author Karl Tauber
+ */
+public class MultiResolutionImageSupport
+{
+	public static boolean isAvailable() {
+		return false;
+	}
+
+	public static boolean isMultiResolutionImage( Image image ) {
+		return false;
+	}
+
+	public static Image create( int baseImageIndex, Image... resolutionVariants ) {
+		return resolutionVariants[baseImageIndex];
+	}
+
+	public static Image map( Image image, Function<Image, Image> mapper ) {
+		return mapper.apply( image );
+	}
+}

flatlaf-core/src/main/java9/com/formdev/flatlaf/util/MultiResolutionImageSupport.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2020 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
+ *
+ *     https://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.Image;
+import java.awt.image.AbstractMultiResolutionImage;
+import java.awt.image.BaseMultiResolutionImage;
+import java.awt.image.MultiResolutionImage;
+import java.util.ArrayList;
+import java.util.IdentityHashMap;
+import java.util.List;
+import java.util.function.Function;
+import javax.swing.ImageIcon;
+
+/**
+ * Support for multi-resolution images available since Java 9.
+ *
+ * @author Karl Tauber
+ */
+public class MultiResolutionImageSupport
+{
+	public static boolean isAvailable() {
+		return true;
+	}
+
+	public static boolean isMultiResolutionImage( Image image ) {
+		return image instanceof MultiResolutionImage;
+	}
+
+	public static Image create( int baseImageIndex, Image... resolutionVariants ) {
+		return new BaseMultiResolutionImage( baseImageIndex, resolutionVariants );
+	}
+
+	public static Image map( Image image, Function<Image, Image> mapper ) {
+		return image instanceof MultiResolutionImage
+			? new MappedMultiResolutionImage( image, mapper )
+			: mapper.apply( image );
+	}
+
+	//---- class MappedMultiResolutionImage -----------------------------------
+
+	private static class MappedMultiResolutionImage
+		extends AbstractMultiResolutionImage
+	{
+		private final Image mrImage;
+		private final Function<Image, Image> mapper;
+		private final IdentityHashMap<Image, Image> cache = new IdentityHashMap<>();
+
+		MappedMultiResolutionImage( Image mrImage, Function<Image, Image> mapper ) {
+			assert mrImage instanceof MultiResolutionImage;
+
+			this.mrImage = mrImage;
+			this.mapper = mapper;
+		}
+
+		@Override
+		public Image getResolutionVariant( double destImageWidth, double destImageHeight ) {
+			Image variant = ((MultiResolutionImage)mrImage).getResolutionVariant( destImageWidth, destImageHeight );
+			return mapAndCacheImage( variant );
+		}
+
+		@Override
+		public List<Image> getResolutionVariants() {
+			List<Image> variants = ((MultiResolutionImage)mrImage).getResolutionVariants();
+			List<Image> mappedVariants = new ArrayList<>();
+			for( Image image : variants )
+				mappedVariants.add( mapAndCacheImage( image ) );
+			return mappedVariants;
+		}
+
+		@Override
+		protected Image getBaseImage() {
+			return mapAndCacheImage( mrImage );
+		}
+
+		private Image mapAndCacheImage( Image image ) {
+			return cache.computeIfAbsent( image, img -> {
+				return new ImageIcon( mapper.apply( img ) ).getImage();
+			} );
+		}
+	}
+}