Added methods for getting normalized list of formats supported by ImageIO + minor clean-up.

imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/ImageReaderBase.java

@@ -302,10 +302,21 @@ public abstract class ImageReaderBase extends ImageReader {
         return IIOUtil.fakeSubsampling(pImage, pParam);
     }
 
+    /**
+     * Tests if param has explicit destination.
+     *
+     * @param pParam the image read parameter, or {@code null}
+     * @return true if {@code pParam} is non-{@code null} and either its {@code getDestination},
+     * {@code getDestinationType} or {@code getDestinationOffset} returns a non-{@code null} value.
+     */
+    protected static boolean hasExplicitDestination(final ImageReadParam pParam) {
+        return (pParam != null && (pParam.getDestination() != null || pParam.getDestinationType() != null || pParam.getDestinationOffset() != null));
+    }
+
     public static void main(String[] pArgs) throws IOException {
         BufferedImage image = ImageIO.read(new File(pArgs[0]));
         if (image == null) {
-            System.err.println("Supported formats: " + Arrays.toString(ImageIO.getReaderFormatNames()));
+            System.err.println("Supported formats: " + Arrays.toString(IIOUtil.getNormalizedReaderFormatNames()));
             System.exit(1);
         }
         showIt(image, pArgs[0]);
@@ -347,10 +358,6 @@ public abstract class ImageReaderBase extends ImageReader {
         }
     }
 
-    protected static boolean hasExplicitDestination(final ImageReadParam pParam) {
-        return (pParam != null && (pParam.getDestination() != null || pParam.getDestinationType() != null || pParam.getDestinationOffset() != null));
-    }
-
     private static class ImageLabel extends JLabel {
         Paint backgroundPaint;
 

imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java

@@ -4,6 +4,7 @@ import com.twelvemonkeys.image.ImageUtil;
 import com.twelvemonkeys.imageio.spi.ProviderInfo;
 
 import javax.imageio.IIOParam;
+import javax.imageio.ImageIO;
 import javax.imageio.spi.IIOServiceProvider;
 import javax.imageio.spi.ServiceRegistry;
 import javax.imageio.stream.ImageInputStream;
@@ -14,6 +15,8 @@ import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 /**
  * IIOUtil
@@ -146,4 +149,35 @@ public final class IIOUtil {
         pRegistry.deregisterServiceProvider(pCategory.cast(pProvider), pCategory);
     }
 
+    /**
+     * Returns a sorted array of format names, that can be read by ImageIO.
+     * The names are all upper-case, and contains no duplicates.
+     *
+     * @return a normalized array of {@code String}s.
+     * @see javax.imageio.ImageIO#getReaderFormatNames()
+     */
+    public static String[] getNormalizedReaderFormatNames() {
+        return normalizeNames(ImageIO.getReaderFormatNames());
+    }
+
+    /**
+     * Returns a sorted array of format names, that can be written by ImageIO.
+     * The names are all upper-case, and contains no duplicates.
+     *
+     * @return a normalized array of {@code String}s.
+     * @see javax.imageio.ImageIO#getWriterFormatNames()  
+     */
+    public static String[] getNormalizedWriterFormatNames() {
+        return normalizeNames(ImageIO.getWriterFormatNames());
+    }
+
+    private static String[] normalizeNames(final String[] names) {
+        SortedSet<String> normalizedNames = new TreeSet<String>();
+
+        for (String name : names) {
+            normalizedNames.add(name.toUpperCase());
+        }
+
+        return normalizedNames.toArray(new String[normalizedNames.size()]);
+    }
 }

imageio/imageio-icns/src/main/java/com/twelvemonkeys/imageio/plugins/icns/ICNSImageReader.java

@@ -463,7 +463,7 @@ public final class ICNSImageReader extends ImageReaderBase {
             // Return blank icon + issue warning. We know the image dimensions, we just can't read the data.
             processWarningOccurred(String.format(
                     "Cannot read %s format in type '%s' icon (no reader; installed: %s)",
-                    format, ICNSUtil.intToStr(resource.type), Arrays.toString(ImageIO.getReaderFormatNames())
+                    format, ICNSUtil.intToStr(resource.type), Arrays.toString(IIOUtil.getNormalizedReaderFormatNames())
             ));
 
             Dimension size = resource.size();