Java tutorial
/** * 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 java.awt.Container; import java.awt.Dimension; import java.awt.Graphics; import java.awt.Image; import java.awt.MediaTracker; import java.awt.image.BufferedImage; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.File; import java.io.IOException; import java.util.List; 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.document.ImageParser; import net.yacy.kelondro.util.FileUtils; import net.yacy.kelondro.util.OS; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.rendering.ImageType; import org.apache.pdfbox.rendering.PDFRenderer; /** * Convert html to an copy on disk-image in a other file format * currently (pdf and/or jpg) */ 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 // the convert command from imagemagick needs ghostscript, if not present on older macs, download a version of gs from http://pages.uoregon.edu/koch/ private final static File wkhtmltopdfMac = new File("/usr/local/bin/wkhtmltopdf"); // sometimes this is also the path on debian private final static File convertMac1 = new File("/opt/local/bin/convert"); private final static File convertMac2 = new File("/opt/ImageMagick/bin/convert"); // debian // to install: apt-get install wkhtmltopdf imagemagick xvfb 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"); private static boolean usexvfb = false; public static boolean wkhtmltopdfAvailable() { return wkhtmltopdfMac.exists() || wkhtmltopdfDebian.exists(); } public static boolean convertAvailable() { return convertMac1.exists() || convertMac2.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, String userAgent, final String acceptLanguage, File destination) { boolean success = false; for (boolean ignoreErrors : new boolean[] { false, true }) { success = writeWkhtmltopdfInternal(url, proxy, destination, userAgent, acceptLanguage, ignoreErrors); if (success) break; if (!success && proxy != null) { ConcurrentLog.warn("Html2Image", "trying to load without proxy: " + url); success = writeWkhtmltopdfInternal(url, null, destination, userAgent, acceptLanguage, ignoreErrors); if (success) break; } } if (success) { ConcurrentLog.info("Html2Image", "wrote " + destination.toString() + " for " + url); } else { ConcurrentLog.warn("Html2Image", "could not generate snapshot for " + url); } return success; } private static boolean writeWkhtmltopdfInternal(final String url, final String proxy, final File destination, final String userAgent, final String acceptLanguage, final boolean ignoreErrors) { final File wkhtmltopdf = wkhtmltopdfMac.exists() ? wkhtmltopdfMac : wkhtmltopdfDebian; String commandline = wkhtmltopdf.getAbsolutePath() + " -q --title '" + url + "' " + //acceptLanguage == null ? "" : "--custom-header 'Accept-Language' '" + acceptLanguage + "' " + //(userAgent == null ? "" : "--custom-header \"User-Agent\" \"" + userAgent + "\" --custom-header-propagation ") + (proxy == null ? "" : "--proxy " + proxy + " ") + (ignoreErrors ? (OS.isMacArchitecture ? "--load-error-handling ignore " : "--ignore-load-errors ") : "") + // some versions do not have that flag and fail if attempting to use it... //"--footer-font-name 'Courier' --footer-font-size 9 --footer-left [webpage] --footer-right [date]/[time]([page]/[topage]) " + "--footer-left [webpage] --footer-right '[date]/[time]([page]/[topage])' --footer-font-size 7 " + url + " " + destination.getAbsolutePath(); try { ConcurrentLog.info("Html2Pdf", "creating pdf from url " + url + " with command: " + commandline); List<String> message; if (!usexvfb) { message = OS.execSynchronous(commandline); if (destination.exists()) return true; ConcurrentLog.warn("Html2Image", "failed to create pdf " + (proxy == null ? "" : "using proxy " + proxy) + " with command: " + commandline); for (String m : message) ConcurrentLog.warn("Html2Image", ">> " + m); } // if this fails, we should try to wrap the X server with a virtual screen using xvfb, this works on headless servers commandline = "xvfb-run -a " + commandline; message = OS.execSynchronous(commandline); if (destination.exists()) { usexvfb = true; return true; } ConcurrentLog.warn("Html2Pdf", "failed to create pdf " + (proxy == null ? "" : "using proxy " + proxy) + " and xvfb with command: " + commandline); for (String m : message) ConcurrentLog.warn("Html2Image", ">> " + m); return false; } catch (IOException e) { e.printStackTrace(); ConcurrentLog.warn("Html2Pdf", "exception while creation of pdf with command: " + commandline); return false; } } /** * convert a pdf (first page) to an image. proper values are i.e. width = 1024, height = 1024, density = 300, quality = 75 * using internal pdf library or external command line tool on linux or mac * @param pdf input pdf file * @param image output jpg file * @param width * @param height * @param density (dpi) * @param quality * @return */ public static boolean pdf2image(File pdf, File image, int width, int height, int density, int quality) { final File convert = convertMac1.exists() ? convertMac1 : convertMac2.exists() ? convertMac2 : convertDebian; // convert pdf to jpg using internal pdfbox capability if (OS.isWindows || !convert.exists()) { try { PDDocument pdoc = PDDocument.load(pdf); BufferedImage bi = new PDFRenderer(pdoc).renderImageWithDPI(0, density, ImageType.RGB); return ImageIO.write(bi, "jpg", image); } catch (IOException ex) { } } // convert on mac or linux using external command line utility 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 String command = convert.getAbsolutePath() + " -density " + density + " -trim " + pdf.getAbsolutePath() + "[0] -trim -resize " + width + "x -crop x" + height + "+0+0 -quality " + quality + "% " + image.getAbsolutePath(); List<String> message = OS.execSynchronous(command); if (image.exists()) return true; ConcurrentLog.warn("Html2Image", "failed to create image with command: " + command); for (String m : message) ConcurrentLog.warn("Html2Image", ">> " + m); // another try for mac: use Image Events using AppleScript in osacript commands... // the following command overwrites a pdf with an png, so we must make a copy first if (!OS.isMacArchitecture) return false; File pngFile = new File(pdf.getAbsolutePath() + ".tmp.pdf"); org.apache.commons.io.FileUtils.copyFile(pdf, pngFile); String[] commandx = { "osascript", "-e", "set ImgFile to \"" + pngFile.getAbsolutePath() + "\"", "-e", "tell application \"Image Events\"", "-e", "set Img to open file ImgFile", "-e", "save Img as PNG", "-e", "end tell" }; //ConcurrentLog.warn("Html2Image", "failed to create image with command: " + commandx); message = OS.execSynchronous(commandx); for (String m : message) ConcurrentLog.warn("Html2Image", ">> " + m); // now we must read and convert this file to a jpg with the target size 1024x1024 try { File newPngFile = new File(pngFile.getAbsolutePath() + ".png"); pngFile.renameTo(newPngFile); Image img = ImageParser.parse(pngFile.getAbsolutePath(), FileUtils.read(newPngFile)); final Image scaled = img.getScaledInstance(width, height, Image.SCALE_AREA_AVERAGING); final MediaTracker mediaTracker = new MediaTracker(new Container()); mediaTracker.addImage(scaled, 0); try { mediaTracker.waitForID(0); } catch (final InterruptedException e) { } // finally write the image final BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); bi.createGraphics().drawImage(scaled, 0, 0, width, height, null); ImageIO.write(bi, "jpg", image); newPngFile.delete(); return image.exists(); } catch (IOException e) { ConcurrentLog.logException(e); return false; } } 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(); } } }