Added support for creating thumbnails or preview bitmaps of fixed size for PNG and TIFF output.

Documentation update for bitmap output.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@820939 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 67 insertions, 8 deletions

diff --git a/src/java/org/apache/fop/render/bitmap/AbstractBitmapDocumentHandler.java b/src/java/org/apache/fop/render/bitmap/AbstractBitmapDocumentHandler.java
index 3449ffe7e..e4606858b 100644
--- a/src/java/org/apache/fop/render/bitmap/AbstractBitmapDocumentHandler.java
+++ b/src/java/org/apache/fop/render/bitmap/AbstractBitmapDocumentHandler.java
@@ -22,9 +22,11 @@ package org.apache.fop.render.bitmap;
 import java.awt.Dimension;
 import java.awt.Graphics2D;
 import java.awt.RenderingHints;
+import java.awt.geom.Point2D;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.util.Map;
 
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.logging.Log;
@@ -53,6 +55,13 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
     /** logging instance */
     private static Log log = LogFactory.getLog(AbstractBitmapDocumentHandler.class);
 
+    /**
+     * Rendering Options key for the controlling the required bitmap size to create.
+     * This is used to create thumbnails, for example. If used, the target resolution is ignored.
+     * Value type: java.awt.Dimension (size in pixels)
+     */
+    public static final String TARGET_BITMAP_SIZE = "target-bitmap-size";
+
     private ImageWriter imageWriter;
     private MultiImageWriter multiImageWriter;
 
@@ -66,6 +75,7 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
     private BitmapRenderingSettings bitmapSettings = new BitmapRenderingSettings();
 
     private double scaleFactor = 1.0;
+    private Dimension targetBitmapSize;
 
     /**
      * Default constructor.
@@ -94,6 +104,9 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
         //Set target resolution
         int dpi = Math.round(context.getUserAgent().getTargetResolution());
         getSettings().getWriterParams().setResolution(dpi);
+
+        Map renderingOptions = getUserAgent().getRendererOptions();
+        setTargetBitmapSize((Dimension)renderingOptions.get(TARGET_BITMAP_SIZE));
     }
 
     /** {@inheritDoc} */
@@ -113,6 +126,17 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
         setFontInfo(fi);
     }
 
+    /**
+     * Sets the target bitmap size (in pixels) of the bitmap that should be produced. Normally,
+     * the bitmap size is calculated automatically based on the page size and the target
+     * resolution. But for example, if you want to create thumbnails or small preview bitmaps
+     * from pages it is more practical (and efficient) to set the required bitmap size.
+     * @param size the target bitmap size (in pixels)
+     */
+    public void setTargetBitmapSize(Dimension size) {
+        this.targetBitmapSize = size;
+    }
+
     //----------------------------------------------------------------------------------------------
 
     /** {@inheritDoc} */
@@ -176,13 +200,43 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
 
     /** {@inheritDoc} */
     public IFPainter startPageContent() throws IFException {
-        double scale = scaleFactor
-            * (25.4f / FopFactoryConfigurator.DEFAULT_TARGET_RESOLUTION)
-                / getUserAgent().getTargetPixelUnitToMillimeter();
-        int bitmapWidth = (int) ((this.currentPageDimensions.width * scale / 1000f) + 0.5f);
-        int bitmapHeight = (int) ((this.currentPageDimensions.height * scale / 1000f) + 0.5f);
+        int bitmapWidth;
+        int bitmapHeight;
+        double scale;
+        Point2D offset = null;
+        if (targetBitmapSize != null) {
+            //Fit the generated page proportionally into the given rectangle (in pixels)
+            double scale2w = 1000 * targetBitmapSize.width
+                / this.currentPageDimensions.getWidth();
+            double scale2h = 1000 * targetBitmapSize.height
+                / this.currentPageDimensions.getHeight();
+            bitmapWidth = targetBitmapSize.width;
+            bitmapHeight = targetBitmapSize.height;
+
+            //Centering the page in the given bitmap
+            offset = new Point2D.Double();
+            if (scale2w < scale2h) {
+                scale = scale2w;
+                double h = this.currentPageDimensions.height * scale / 1000;
+                offset.setLocation(0, (bitmapHeight - h) / 2.0);
+            } else {
+                scale = scale2h;
+                double w = this.currentPageDimensions.width * scale / 1000;
+                offset.setLocation((bitmapWidth - w) / 2.0, 0);
+            }
+        } else {
+            //Normal case: just scale according to the target resolution
+            scale = scaleFactor
+                * getUserAgent().getTargetResolution()
+                / FopFactoryConfigurator.DEFAULT_TARGET_RESOLUTION;
+            bitmapWidth = (int) ((this.currentPageDimensions.width * scale / 1000f) + 0.5f);
+            bitmapHeight = (int) ((this.currentPageDimensions.height * scale / 1000f) + 0.5f);
+        }
+
+        //Set up bitmap to paint on
         this.currentImage = createBufferedImage(bitmapWidth, bitmapHeight);
         Graphics2D graphics2D = this.currentImage.createGraphics();
+
         // draw page background
         if (!getSettings().hasTransparentPageBackground()) {
             graphics2D.setBackground(getSettings().getPageBackgroundColor());
@@ -190,6 +244,7 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
             graphics2D.fillRect(0, 0, bitmapWidth, bitmapHeight);
         }
 
+        //Set rendering hints
         graphics2D.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS,
                 RenderingHints.VALUE_FRACTIONALMETRICS_ON);
         if (getSettings().isAntiAliasingEnabled()
@@ -213,6 +268,11 @@ public abstract class AbstractBitmapDocumentHandler extends AbstractBinaryWritin
         }
         graphics2D.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL,
                 RenderingHints.VALUE_STROKE_PURE);
+
+        //Set up initial coordinate system for the page
+        if (offset != null) {
+            graphics2D.translate(offset.getX(), offset.getY());
+        }
         graphics2D.scale(scale / 1000f, scale / 1000f);
 
         return new Java2DPainter(graphics2D, getContext(), getFontInfo());
diff --git a/src/java/org/apache/fop/render/bitmap/BitmapRendererConfigurator.java b/src/java/org/apache/fop/render/bitmap/BitmapRendererConfigurator.java
index 5237dbe35..1b6c43700 100644
--- a/src/java/org/apache/fop/render/bitmap/BitmapRendererConfigurator.java
+++ b/src/java/org/apache/fop/render/bitmap/BitmapRendererConfigurator.java
@@ -19,7 +19,6 @@
 
 package org.apache.fop.render.bitmap;
 
-import java.awt.Color;
 import java.awt.Graphics2D;
 import java.awt.image.BufferedImage;
 import java.util.List;
@@ -80,8 +79,6 @@ public class BitmapRendererConfigurator extends Java2DRendererConfigurator
                 if (background != null) {
                     settings.setPageBackgroundColor(
                             ColorUtil.parseColorString(this.userAgent, background));
-                } else {
-                    settings.setPageBackgroundColor(Color.WHITE);
                 }
             }
 
@@ -106,6 +103,8 @@ public class BitmapRendererConfigurator extends Java2DRendererConfigurator
                     settings.setBufferedImageType(BufferedImage.TYPE_BYTE_GRAY);
                 } else if ("binary".equalsIgnoreCase(color)) {
                     settings.setBufferedImageType(BufferedImage.TYPE_BYTE_BINARY);
+                } else if ("bi-level".equalsIgnoreCase(color)) {
+                    settings.setBufferedImageType(BufferedImage.TYPE_BYTE_BINARY);
                 } else {
                     throw new FOPException("Invalid value for color-mode: " + color);
                 }