Cache (and scale) custom emblem images

2 files changed, 152 insertions, 2 deletions

diff --git a/pdf-over-signator/src/main/java/at/asit/pdfover/signator/CachedFileNameEmblem.java b/pdf-over-signator/src/main/java/at/asit/pdfover/signator/CachedFileNameEmblem.java
new file mode 100644
index 00000000..dc54d84a
--- /dev/null
+++ b/pdf-over-signator/src/main/java/at/asit/pdfover/signator/CachedFileNameEmblem.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright 2012 by A-SIT, Secure Information Technology Center Austria
+ *
+ * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
+ * the European Commission - subsequent versions of the EUPL (the "Licence");
+ * You may not use this work except in compliance with the Licence.
+ * You may obtain a copy of the Licence at:
+ * http://joinup.ec.europa.eu/software/page/eupl
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the Licence is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing permissions and
+ * limitations under the Licence.
+ */
+package at.asit.pdfover.signator;
+
+// Imports
+import java.awt.Graphics2D;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Properties;
+
+import javax.imageio.ImageIO;
+
+import org.apache.commons.codec.digest.DigestUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * 
+ */
+public class CachedFileNameEmblem implements Emblem {
+	/**
+	 * SLF4J Logger instance
+	 **/
+	private static final Logger log = LoggerFactory
+			.getLogger(CachedFileNameEmblem.class);
+
+	private String fileName = null;
+
+	/**
+	 * Constructor
+	 * @param filename
+	 */
+	public CachedFileNameEmblem(String filename) {
+		this.fileName = filename;
+	}
+
+	private String getFileHash(String filename) throws IOException {
+		InputStream is = Files.newInputStream(Paths.get(this.fileName));
+		return DigestUtils.md5Hex(is);
+	}
+
+	/* (non-Javadoc)
+	 * @see at.asit.pdfover.signator.Emblem#getFileName()
+	 */
+	@Override
+	public String getFileName() {
+		final String fileDir = System.getProperty("user.home") + File.separator + ".pdf-over"; //$NON-NLS-1$ //$NON-NLS-2$
+		final String imgFileName = ".emblem"; //$NON-NLS-1$
+		final String imgFileExt = "png"; //$NON-NLS-1$
+		final String propFileName = ".emblem.properties"; //$NON-NLS-1$
+
+		final String imgProp = "IMG"; //$NON-NLS-1$
+		final String hshProp = "HSH"; //$NON-NLS-1$
+		final int maxWidth  = 480;
+		final int maxHeight = 600;
+
+		String emblemImg = this.fileName;
+		String emblemHsh = null;
+		String cachedEmblemFileName = fileDir + File.separator + imgFileName + "." + imgFileExt; //$NON-NLS-1$
+
+		if (emblemImg == null || !(new File(emblemImg).exists()))
+			return null;
+
+		Properties emblemProps = new Properties();
+		// compare cache, try to load if match
+		try {
+			InputStream in = new FileInputStream(new File(fileDir, propFileName));
+			emblemProps.load(in);
+			if (emblemImg.equals(emblemProps.getProperty(imgProp))) {
+				emblemHsh = getFileHash(emblemImg);
+				if (emblemHsh.equals(emblemProps.getProperty(hshProp))) {
+					log.debug("Emblem cache hit: " + cachedEmblemFileName); //$NON-NLS-1$
+					return cachedEmblemFileName; //$NON-NLS-1$
+				}
+			}
+			log.debug("Emblem cache miss");
+		} catch (Exception e) {
+			log.warn("Can't load emblem cache", e); //$NON-NLS-1$
+		}
+
+		try {
+			// create new cache
+			if (emblemHsh == null)
+				emblemHsh = getFileHash(emblemImg);
+			emblemProps.setProperty(imgProp, emblemImg);
+			emblemProps.setProperty(hshProp, emblemHsh);
+			BufferedImage img = ImageIO.read(new File(emblemImg));
+			int oheight = img.getHeight();
+			int owidth = img.getWidth();
+			double ratio = (double)owidth/(double)oheight;
+
+			int height = oheight;
+			int width = owidth;
+			if (height > maxHeight) {
+				height = maxHeight;
+				width = (int) (maxHeight * ratio);
+			}
+			if (width > maxWidth) {
+				width = maxWidth;
+				height = (int) (maxWidth / ratio);
+			}
+			BufferedImage cacheImg = img;
+			if (width != owidth || height == oheight) {
+				//scale image
+				log.debug("Scaling emblem: " + owidth + "x" + oheight + " to " + width + "x" + height); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
+				cacheImg = new BufferedImage(width, height, img.getType() == 0 ? BufferedImage.TYPE_INT_ARGB : img.getType());
+				Graphics2D g = cacheImg.createGraphics();
+				g.drawImage(img, 0, 0, width, height, null);
+				g.dispose();
+			}
+
+			File file = new File(fileDir, imgFileName + "." + imgFileExt); //$NON-NLS-1$
+			ImageIO.write(cacheImg, imgFileExt, file); // ignore returned boolean
+			OutputStream out = new FileOutputStream(new File(fileDir, propFileName));
+			emblemProps.store(out, null);
+		} catch (IOException e) {
+			log.error("Can't save emblem cache", e); //$NON-NLS-1$
+			return this.fileName;
+		}
+		return cachedEmblemFileName;
+	}
+
+	/**
+	 * Return the original filename
+	 * @return the original filename
+	 */
+	public String getOriginalFileName() {
+		return this.fileName;
+	}
+}
diff --git a/pdf-over-signator/src/main/java/at/asit/pdfover/signator/SignatureParameter.java b/pdf-over-signator/src/main/java/at/asit/pdfover/signator/SignatureParameter.java
index 8b08e3dd..8e1b965e 100644
--- a/pdf-over-signator/src/main/java/at/asit/pdfover/signator/SignatureParameter.java
+++ b/pdf-over-signator/src/main/java/at/asit/pdfover/signator/SignatureParameter.java
@@ -162,9 +162,9 @@ public abstract class SignatureParameter {
 	public abstract SignatureDimension getPlaceholderDimension();
 
 	/**
-	 * Gets the Dimension to display the Placeholder
+	 * Gets the Placeholder image
 	 * 
-	 * @return the placeholder dimensions
+	 * @return the placeholder image
 	 */
 	public abstract Image getPlaceholder();