src/java.desktop/share/classes/java/awt/Toolkit.java

@@ -32,10 +32,11 @@
 import java.awt.event.*;
 import java.awt.im.InputMethodHighlight;
 import java.awt.image.ColorModel;
 import java.awt.image.ImageObserver;
 import java.awt.image.ImageProducer;
+import java.awt.image.MultiResolutionImage;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
 import java.beans.PropertyChangeSupport;
 import java.io.File;
 import java.io.FileInputStream;

@@ -45,11 +46,10 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.MissingResourceException;
 import java.util.Properties;
 import java.util.ResourceBundle;
-import java.util.StringTokenizer;
 import java.util.WeakHashMap;
 
 import sun.awt.AWTAccessor;
 import sun.awt.AWTPermissions;
 import sun.awt.AppContext;

@@ -58,14 +58,17 @@
 import sun.awt.SunToolkit;
 
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.Arrays;
+import java.util.LinkedList;
 import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.stream.Collectors;
 import javax.accessibility.AccessibilityProvider;
+import sun.awt.image.MultiResolutionToolkitImage;
+import sun.awt.image.MultiResolutionToolkitImage.ResolutionVariantItem;
 
 /**
  * This class is the abstract superclass of all actual
  * implementations of the Abstract Window Toolkit. Subclasses of
  * the {@code Toolkit} class are used to bind the various components

@@ -636,10 +639,133 @@
      * @see #createImage(java.lang.String)
      */
     public abstract Image getImage(String filename);
 
     /**
+     * The MediaResolutionNamingScheme class stores the resolution variant
+     * qualifier as well as scaled factors associated with it.
+     *
+     * @see #getImageUsingNamingSchemes
+     * @see MultiResolutionImage
+     *
+     * @since 9
+     */
+    public static class MediaResolutionNamingScheme {
+
+        private final String qualifier;
+        private final float scale;
+
+        /**
+         * Creates a new instance of MediaResolutionNamingScheme.
+         *
+         * @param qualifier the resolution-variant qualifier
+         * @param scale the scale associated with the resolution variant qualifier
+         *
+         * @since 9
+         */
+        public MediaResolutionNamingScheme(String qualifier, float scale) {
+            this.qualifier = qualifier;
+            this.scale = scale;
+        }
+
+        /**
+         * @return the resolution-variant qualifier
+         *
+         * @since 9
+         */
+
+        public String getQualifier() {
+            return qualifier;
+        }
+
+        /**
+         * @return scale factor
+         *
+         * @since 9
+         */
+        public float getScale() {
+            return scale;
+        }
+    }
+
+    /**
+     * Returns an image with resolution variants based on the provided media
+     * resolution naming scheme. This method is useful when it is necessary to
+     * provide an image with resolution variants for HiDPI displays.
+     * <p>
+     * For example, if HiDPI display supports scales 1.5 and 2 the following steps
+     * can be used to provide an image together with its high resolution variants.
+     * Put scaled versions of the original image in the same directory using
+     * naming convention {@literal @150pct} for scale 1.5 and {@literal @2x}
+     * for scale 2 The qualifier need to be placed between the image
+     * name and extension:
+     * <ul>
+     *   <li>{@literal image_name.ext} - original image</li>
+     *   <li>{@literal image_name@150pct.ext} - resolution variant for scale 1.5
+     *       and qualifier {@literal @150pct}</li>
+     *   <li>{@literal image_name@2x.ext} - resolution variant for scale 2 and
+     *       qualifier {@literal @2x}</li>
+     * </ul>
+     * Call {@code getImageUsingNamingSchemes)} method providing only path to the
+     * original image and naming schemes which include defined quilifiers and scales.
+     * <pre> {@code
+     *   Image image = toolkit.getImageUsingNamingSchemes(fileName,
+     *           new Toolkit.MediaResolutionNamingScheme("@150pct", 1.5f),
+     *           new Toolkit.MediaResolutionNamingScheme("@2x", 2f)
+     *   );
+     * } </pre>
+     * <p>
+     * The resolution variant is not added if an image for the given naming scheme
+     * is missed. If all resolution variants are missed the returned result
+     * will be the same as call to the {@code getImage(fileName)} method.
+     *
+     * @param fileName file path to the original image
+     * @param namingSchemes array of naming scheme that contains resolution
+     *        variant qualifier and associated with it scale factor
+     * @return an image with with resolution variants
+     *
+     * @see #getImage
+     * @see MediaResolutionNamingScheme
+     * @see MultiResolutionImage
+     */
+    public Image getImageUsingNamingSchemes(String fileName,
+            MediaResolutionNamingScheme... namingSchemes) {
+
+        Image baseimage = getImage(fileName);
+
+        if (namingSchemes.length == 0
+                || (baseimage instanceof MultiResolutionImage)) {
+            return baseimage;
+        }
+
+        int slash = fileName.lastIndexOf('/');
+        String name = (slash < 0) ? fileName : fileName.substring(slash + 1);
+
+        int dot = name.lastIndexOf('.');
+        String ext = (dot < 0) ? "" : name.substring(dot);
+        name = (dot < 0) ? name : name.substring(0, dot);
+        String prefix = (slash < 0) ? name : fileName.substring(0, slash + 1) + name;
+
+        java.util.List<ResolutionVariantItem> rvItems = new LinkedList<>();
+
+        for (MediaResolutionNamingScheme scheme : namingSchemes) {
+            String rvFileName = prefix + scheme.getQualifier() + ext;
+            if (SunToolkit.imageExists(rvFileName)) {
+                Image rvImage = toolkit.getImage(rvFileName);
+                float scale = scheme.getScale();
+                rvItems.add(new ResolutionVariantItem(rvImage, scale, scale));
+            }
+        }
+
+        if (rvItems.isEmpty()) {
+            return baseimage;
+        }
+
+        return new MultiResolutionToolkitImage(baseimage, rvItems);
+    }
+
+    /**
      * Returns an image which gets pixel data from the specified URL.
      * The pixel data referenced by the specified URL must be in one
      * of the following formats: GIF, JPEG or PNG.
      * The underlying toolkit attempts to resolve multiple requests
      * with the same URL to the same returned Image.