(no commit message)

diff --git a/gps/src/org/wamblee/utils/JpegUtils.java b/gps/src/org/wamblee/utils/JpegUtils.java
new file mode 100644 (file)
index 0000000..abeea40
--- /dev/null
+++ b/gps/src/org/wamblee/utils/JpegUtils.java
@@ -0,0 +1,108 @@
+/*
+ * Copyright 2006 the original author or authors.
+ * 
+ * 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 org.wamblee.utils;
+
+import java.awt.Container;
+import java.awt.Graphics2D;
+import java.awt.Image;
+import java.awt.MediaTracker;
+import java.awt.RenderingHints;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import sun.awt.image.codec.JPEGImageDecoderImpl;
+
+import com.sun.image.codec.jpeg.JPEGCodec;
+import com.sun.image.codec.jpeg.JPEGEncodeParam;
+import com.sun.image.codec.jpeg.JPEGImageDecoder;
+import com.sun.image.codec.jpeg.JPEGImageEncoder;
+
+/**
+ * Utility functions for processing JPEG images. 
+ */
+public class JpegUtils {
+    /**
+     * Scales an image preserving the aspect ratio. 
+     * 
+     * @param aMaxWidth Maximum width. 
+     * @param aMaxHeight Maximum height. 
+     * @param aImage Image to scale. 
+     * @return Scaled image. 
+     */
+    public static BufferedImage scaleImage(int aMaxWidth, int aMaxHeight, Image aImage) {
+        double thumbRatio = (double) aMaxWidth / (double) aMaxHeight;
+        int imageWidth = aImage.getWidth(null);
+        int imageHeight = aImage.getHeight(null);
+        double imageRatio = (double) imageWidth / (double) imageHeight;
+        if (thumbRatio < imageRatio) {
+            aMaxHeight = (int) (aMaxWidth / imageRatio);
+        } else {
+            aMaxWidth = (int) (aMaxHeight * imageRatio);
+        }
+        BufferedImage thumbImage = new BufferedImage(aMaxWidth, aMaxHeight,
+                BufferedImage.TYPE_INT_RGB);
+        Graphics2D graphics2D = thumbImage.createGraphics();
+        graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
+                RenderingHints.VALUE_INTERPOLATION_BILINEAR);
+        graphics2D.drawImage(aImage, 0, 0, aMaxWidth, aMaxHeight, null);
+        return thumbImage;
+    }
+
+    /**
+     * Loads a jpeg image from an input stream.
+     *  
+     * @param aInput Input stream. 
+     * @return JPEG image. 
+     * @throws IOException In case of IO problems.  
+     * @throws InterruptedException When execution is interrupted. 
+     */
+    public static BufferedImage loadJpegImage(InputStream aInput) throws IOException, InterruptedException {
+        JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(aInput);
+        BufferedImage image = decoder.decodeAsBufferedImage();
+        MediaTracker mediaTracker = new MediaTracker(new Container());
+        mediaTracker.addImage(image, 0);
+        mediaTracker.waitForID(0);
+        return image;
+    }
+
+    /**
+     * Writes a JPEG image. 
+     * 
+     * @param aOutput Output stream to write to. 
+     * @param aQuality Quality of the JPEG image in the range 0..100
+     * @param aThumbImage
+     * @throws IOException
+     */
+    public static void writeJpegImage(OutputStream aOutput, int aQuality, BufferedImage aThumbImage) throws IOException {
+        // save thumbnail image to OUTFILE
+        
+        if ( aQuality < 0 || aQuality > 100 ) {
+            throw new IllegalArgumentException("Argument quality must be in range 0.100: " + aQuality); 
+        }
+            
+        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(aOutput);
+        JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(aThumbImage);
+        aQuality = Math.max(0, Math.min(aQuality, 100));
+        param.setQuality((float) aQuality / 100.0f, false);
+        encoder.setJPEGEncodeParam(param);
+        encoder.encode(aThumbImage);
+    }
+
+}
+