added image screenshot generator

source/net/yacy/cora/util/Html2Image.java

@@ -0,0 +1,181 @@
+/**
+ *  Html2Image
+ *  Copyright 2014 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
+ *  First published 26.11.2014 on http://yacy.net
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program in the file lgpl21.txt
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.yacy.cora.util;
+
+import javax.imageio.ImageIO;
+import javax.swing.JEditorPane;
+import javax.swing.text.Document;
+import javax.swing.text.Element;
+import javax.swing.text.View;
+import javax.swing.text.ViewFactory;
+import javax.swing.text.html.HTMLDocument;
+import javax.swing.text.html.HTMLEditorKit;
+import javax.swing.text.html.ImageView;
+
+import net.yacy.kelondro.util.OS;
+
+import java.awt.Dimension;
+import java.awt.Graphics;
+import java.awt.image.BufferedImage;
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Html2Image {
+    
+    // Mac
+    // to install wkhtmltopdf, download wkhtmltox-0.12.1_osx-cocoa-x86-64.pkg from http://wkhtmltopdf.org/downloads.html
+    // to install imagemagick, download from http://cactuslab.com/imagemagick/assets/ImageMagick-6.8.9-9.pkg.zip
+    private final static File wkhtmltopdfMac = new File("/usr/local/bin/wkhtmltopdf");
+    private final static File convertMac = new File("/opt/local/bin/convert");
+    
+    // debian
+    // to install: apt-get install wkhtmltopdf imagemagick
+    private final static File wkhtmltopdfDebian = new File("/usr/bin/wkhtmltopdf"); // there is no wkhtmltoimage, use convert to create images
+    private final static File convertDebian = new File("/usr/bin/convert");
+
+
+    public boolean wkhtmltopdfAvailable() {
+        return wkhtmltopdfMac.exists() || wkhtmltopdfDebian.exists();
+    }
+    
+    public boolean convertAvailable() {
+        return convertMac.exists() || convertDebian.exists();
+    }
+    
+    /**
+     * write a pdf of a web page
+     * @param url
+     * @param proxy must be of the form http://host:port; use YaCy here as proxy which is mostly http://localhost:8090
+     * @param destination
+     * @return
+     */
+    public static boolean writeWkhtmltopdf(String url, String proxy, File destination) {
+        final File wkhtmltopdf = wkhtmltopdfMac.exists() ? wkhtmltopdfMac : wkhtmltopdfDebian;
+        
+        try {
+            OS.execSynchronous(wkhtmltopdf.getAbsolutePath() + (proxy == null ? " " : " --proxy " + proxy + " ") + url + " " + destination.getAbsolutePath());
+            return destination.exists();
+        } catch (IOException e) {
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+    /**
+     * convert a pdf to an image. proper values are i.e. width = 1024, height = 1024, density = 300, quality = 75
+     * @param pdf
+     * @param image
+     * @param width
+     * @param height
+     * @param density
+     * @param quality
+     * @return
+     */
+    public static boolean pdf2image(File pdf, File image, int width, int height, int density, int quality) {
+        final File convert = convertMac.exists() ? convertMac : convertDebian;
+        
+        try {
+            // i.e. convert -density 300 -trim yacy.pdf[0] -trim -resize 1024x -crop x1024+0+0 -quality 75% yacy-convert-300.jpg
+            // note: both -trim are necessary, otherwise it is trimmed only on one side. The [0] selects the first page of the pdf
+            OS.execSynchronous(convert.getAbsolutePath() + " -density " + density + " -trim " + pdf.getAbsolutePath() + "[0] -trim -resize " + width + "x -crop x" + height + "+0+0 -quality " + quality + "% " + image.getAbsolutePath());
+            return image.exists();
+        } catch (IOException e) {
+            e.printStackTrace();
+            return false;
+        }
+    }
+    
+    /**
+     * render a html page with a JEditorPane, which can do html up to html v 3.2. No CSS supported!
+     * @param url
+     * @param size
+     * @throws IOException 
+     */
+    public static void writeSwingImage(String url, Dimension size, File destination) throws IOException {
+        
+        // set up a pane for rendering
+        final JEditorPane htmlPane = new JEditorPane();
+        htmlPane.setSize(size);
+        htmlPane.setEditable(false);
+        final HTMLEditorKit kit = new HTMLEditorKit() {
+
+            private static final long serialVersionUID = 1L;
+
+            @Override
+            public Document createDefaultDocument() {
+                HTMLDocument doc = (HTMLDocument) super.createDefaultDocument();
+                doc.setAsynchronousLoadPriority(-1);
+                return doc;
+            }
+
+            @Override
+            public ViewFactory getViewFactory() {
+                return new HTMLFactory() {
+                    @Override
+                    public View create(Element elem) {
+                        View view = super.create(elem);
+                        if (view instanceof ImageView) {
+                            ((ImageView) view).setLoadsSynchronously(true);
+                        }
+                        return view;
+                    }
+                };
+            }
+        };
+        htmlPane.setEditorKitForContentType("text/html", kit);
+        htmlPane.setContentType("text/html");
+        htmlPane.addPropertyChangeListener(new PropertyChangeListener() {
+            @Override
+            public void propertyChange(PropertyChangeEvent evt) {
+            }
+        });
+        
+        // load the page
+        try {
+            htmlPane.setPage(url);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        
+        // render the page
+        Dimension prefSize = htmlPane.getPreferredSize();
+        BufferedImage img = new BufferedImage(prefSize.width, htmlPane.getPreferredSize().height, BufferedImage.TYPE_INT_ARGB);
+        Graphics graphics = img.getGraphics();
+        htmlPane.setSize(prefSize);
+        htmlPane.paint(graphics);
+        ImageIO.write(img, destination.getName().endsWith("jpg") ? "jpg" : "png", destination);
+    }
+    
+    public static void main(String[] args) {
+        try {
+            Html2Image.writeSwingImage(args[0], new Dimension(1200, 2000), new File(args[1]));
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+    
+}