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| author | Yegor Kozlov <yegor@apache.org> | 2009-11-06 19:08:41 +0000 |
|---|---|---|
| committer | Yegor Kozlov <yegor@apache.org> | 2009-11-06 19:08:41 +0000 |
| commit | 1aeb476ce7a680346ceacb59cf4596719f82c334 (patch) | |
| tree | c373c597b665148fb5cd79c124121e6994523a3b /src/java/org/apache/poi/ss/util | |
| parent | 43af361c5c400a64c83cd994b1f29ab4febab857 (diff) | |
| download | poi-1aeb476ce7a680346ceacb59cf4596719f82c334.tar.gz poi-1aeb476ce7a680346ceacb59cf4596719f82c334.zip | |
release system resources when calling javax.imageio.ImageIO in Picture.resize()
git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@833527 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'src/java/org/apache/poi/ss/util')
| -rwxr-xr-x | src/java/org/apache/poi/ss/util/ImageUtils.java | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/src/java/org/apache/poi/ss/util/ImageUtils.java b/src/java/org/apache/poi/ss/util/ImageUtils.java new file mode 100755 index 0000000000..76ebc0370c --- /dev/null +++ b/src/java/org/apache/poi/ss/util/ImageUtils.java @@ -0,0 +1,116 @@ +/* ====================================================================
+ 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.
+==================================================================== */
+package org.apache.poi.ss.util;
+
+import org.w3c.dom.NodeList;
+import org.w3c.dom.Element;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.util.POILogger;
+import org.apache.poi.util.POILogFactory;
+
+import javax.imageio.ImageReader;
+import javax.imageio.ImageIO;
+import javax.imageio.stream.ImageInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.util.Iterator;
+
+/**
+ * @author Yegor Kozlov
+ */
+public class ImageUtils {
+ private static final POILogger logger = POILogFactory.getLogger(ImageUtils.class);
+
+ public static final int PIXEL_DPI = 96;
+
+ /**
+ * Return the dimension of this image
+ *
+ * @param is the stream containing the image data
+ * @param type type of the picture: {@link org.apache.poi.ss.usermodel.Workbook#PICTURE_TYPE_JPEG},
+ * {@link org.apache.poi.ss.usermodel.Workbook#PICTURE_TYPE_PNG} or {@link org.apache.poi.ss.usermodel.Workbook#PICTURE_TYPE_DIB}
+ *
+ * @return image dimension in pixels
+ */
+ public static Dimension getImageDimension(InputStream is, int type){
+ Dimension size = new Dimension();
+
+ switch (type){
+ //we can calculate the preferred size only for JPEG, PNG and BMP
+ //other formats like WMF, EMF and PICT are not supported in Java
+ case Workbook.PICTURE_TYPE_JPEG:
+ case Workbook.PICTURE_TYPE_PNG:
+ case Workbook.PICTURE_TYPE_DIB:
+ try {
+ //read the image using javax.imageio.*
+ ImageInputStream iis = ImageIO.createImageInputStream( is );
+ Iterator i = ImageIO.getImageReaders( iis );
+ ImageReader r = (ImageReader) i.next();
+ r.setInput( iis );
+ BufferedImage img = r.read(0);
+
+ int[] dpi = getResolution(r);
+
+ //if DPI is zero then assume standard 96 DPI
+ //since cannot divide by zero
+ if (dpi[0] == 0) dpi[0] = PIXEL_DPI;
+ if (dpi[1] == 0) dpi[1] = PIXEL_DPI;
+
+ size.width = img.getWidth()*PIXEL_DPI/dpi[0];
+ size.height = img.getHeight()*PIXEL_DPI/dpi[1];
+
+ r.dispose();
+ iis.close();
+
+ } catch (IOException e){
+ //silently return if ImageIO failed to read the image
+ logger.log(POILogger.WARN, e);
+ }
+
+ break;
+ default:
+ logger.log(POILogger.WARN, "Only JPEG, PNG and DIB pictures can be automatically sized");
+ }
+ return size;
+ }
+
+ /**
+ * The metadata of PNG and JPEG can contain the width of a pixel in millimeters.
+ * Return the the "effective" dpi calculated as <code>25.4/HorizontalPixelSize</code>
+ * and <code>25.4/VerticalPixelSize</code>. Where 25.4 is the number of mm in inch.
+ *
+ * @return array of two elements: <code>{horisontalPdi, verticalDpi}</code>.
+ * {96, 96} is the default.
+ */
+ public static int[] getResolution(ImageReader r) throws IOException {
+ int hdpi=96, vdpi=96;
+ double mm2inch = 25.4;
+
+ NodeList lst;
+ Element node = (Element)r.getImageMetadata(0).getAsTree("javax_imageio_1.0");
+ lst = node.getElementsByTagName("HorizontalPixelSize");
+ if(lst != null && lst.getLength() == 1) hdpi = (int)(mm2inch/Float.parseFloat(((Element)lst.item(0)).getAttribute("value")));
+
+ lst = node.getElementsByTagName("VerticalPixelSize");
+ if(lst != null && lst.getLength() == 1) vdpi = (int)(mm2inch/Float.parseFloat(((Element)lst.item(0)).getAttribute("value")));
+
+ return new int[]{hdpi, vdpi};
+ }
+
+}
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