Extracted some bitmap handling functions from the PCL implementation into new BitmapImageUtil class.

Added limited support for more efficient image encoding in AFP. Where possible the raw image data from the RenderedImage is used. Limitations include:
- missing support for color lookup tables (IndexColorModel)
- monochrome images: additive/subtractive flag is not supported by the AFP library, yet.
Images with fewer bits per pixel than specified in the configuration are no longer blown up to 4, 8 or even 24 bits.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@734737 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 173 insertions, 0 deletions

diff --git a/src/java/org/apache/fop/util/BitmapImageUtil.java b/src/java/org/apache/fop/util/BitmapImageUtil.java
new file mode 100644
index 000000000..278587b64
--- /dev/null
+++ b/src/java/org/apache/fop/util/BitmapImageUtil.java
@@ -0,0 +1,173 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.util;
+
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.Graphics2D;
+import java.awt.geom.AffineTransform;
+import java.awt.image.BufferedImage;
+import java.awt.image.ColorModel;
+import java.awt.image.IndexColorModel;
+import java.awt.image.RenderedImage;
+
+/**
+ * Utility method for dealing with bitmap images.
+ */
+public class BitmapImageUtil {
+
+    /**
+     * Indicates whether an image is a monochrome (1 bit black and white) image.
+     * @param img the image
+     * @return true if it's a monochrome image
+     */
+    public static final boolean isMonochromeImage(RenderedImage img) {
+        return (getColorIndexSize(img) == 2);
+    }
+
+    /**
+     * Indicates whether a zero bit indicates a black/dark pixel for a monochrome image.
+     * @param img the image (must be 1 bit monochrome)
+     * @return true if a zero bit indicates a black/dark pixel, false for a white/bright pixel
+     */
+    public static final boolean isZeroBlack(RenderedImage img) {
+        if (!isMonochromeImage(img)) {
+            throw new IllegalArgumentException("Image is not a monochrome image!");
+        }
+        IndexColorModel icm = (IndexColorModel)img.getColorModel();
+        int gray0 = convertToGray(icm.getRGB(0));
+        int gray1 = convertToGray(icm.getRGB(1));
+        return gray0 < gray1;
+    }
+
+    /**
+     * Convert an RGB color value to a grayscale from 0 to 100.
+     * @param r the red component
+     * @param g the green component
+     * @param b the blue component
+     * @return the gray value
+     */
+    public static final int convertToGray(int r, int g, int b) {
+        return (r * 30 + g * 59 + b * 11) / 100;
+    }
+
+    /**
+     * Convert an RGB color value to a grayscale from 0 to 100.
+     * @param rgb the RGB value
+     * @return the gray value
+     */
+    public static final int convertToGray(int rgb) {
+        int r = (rgb & 0xFF0000) >> 16;
+        int g = (rgb & 0xFF00) >> 8;
+        int b = rgb & 0xFF;
+        return convertToGray(r, g, b);
+    }
+
+    /**
+     * Returns the size of the color index if the given image has one.
+     * @param img the image
+     * @return the size of the color index or 0 if there's no color index
+     */
+    public static final int getColorIndexSize(RenderedImage img) {
+        ColorModel cm = img.getColorModel();
+        if (cm instanceof IndexColorModel) {
+            IndexColorModel icm = (IndexColorModel)cm;
+            return icm.getMapSize();
+        } else {
+            return 0;
+        }
+    }
+
+    /**
+     * Indicates whether an image is a grayscale image.
+     * @param img the image
+     * @return true if it's a grayscale image
+     */
+    public static final boolean isGrayscaleImage(RenderedImage img) {
+        return (img.getColorModel().getColorSpace().getNumComponents() == 1);
+    }
+
+    /**
+     * Converts an image to sRGB. Optionally, the image can be scaled.
+     * @param img the image to be converted
+     * @param targetDimension the new target dimensions or null if no scaling is necessary
+     * @return the sRGB image
+     */
+    public static final BufferedImage convertTosRGB(RenderedImage img,
+            Dimension targetDimension) {
+        return convertAndScaleImage(img, targetDimension, BufferedImage.TYPE_INT_RGB);
+    }
+
+    /**
+     * Converts an image to a grayscale (8 bits) image. Optionally, the image can be scaled.
+     * @param img the image to be converted
+     * @param targetDimension the new target dimensions or null if no scaling is necessary
+     * @return the grayscale image
+     */
+    public static final BufferedImage convertToGrayscale(RenderedImage img,
+            Dimension targetDimension) {
+        return convertAndScaleImage(img, targetDimension, BufferedImage.TYPE_BYTE_GRAY);
+    }
+
+    /**
+     * Converts an image to a monochrome 1-bit image. Optionally, the image can be scaled.
+     * @param img the image to be converted
+     * @param targetDimension the new target dimensions or null if no scaling is necessary
+     * @return the monochrome image
+     */
+    public static final BufferedImage convertToMonochrome(RenderedImage img,
+            Dimension targetDimension) {
+        return convertAndScaleImage(img, targetDimension, BufferedImage.TYPE_BYTE_BINARY);
+    }
+
+    private static BufferedImage convertAndScaleImage(RenderedImage img,
+            Dimension targetDimension, int imageType) {
+        Dimension bmpDimension = targetDimension;
+        if (bmpDimension == null) {
+            bmpDimension = new Dimension(img.getWidth(), img.getHeight());
+        }
+        BufferedImage target = new BufferedImage(bmpDimension.width, bmpDimension.height,
+                imageType);
+        transferImage(img, target);
+        return target;
+    }
+
+    private static void transferImage(RenderedImage source, BufferedImage target) {
+        Graphics2D g2d = target.createGraphics();
+        try {
+            g2d.setBackground(Color.white);
+            g2d.setColor(Color.black);
+            g2d.clearRect(0, 0, target.getWidth(), target.getHeight());
+
+            AffineTransform at = new AffineTransform();
+            if (source.getWidth() != target.getWidth()
+                    || source.getHeight() != target.getHeight()) {
+                double sx = target.getWidth() / (double)source.getWidth();
+                double sy = target.getHeight() / (double)source.getHeight();
+                at.scale(sx, sy);
+            }
+            g2d.drawRenderedImage(source, at);
+        } finally {
+            g2d.dispose();
+        }
+    }
+
+
+}