Miniatura de una página PDF (Java)

Question

¿Cómo puedo generar una imagen en miniatura de páginas en un documento PDF utilizando Java?

Answer 1

Creo http://pdfbox.apache.org/ hará lo que usted está buscando ya que se puede crear una imagen de una página y luego escalar la imagen

de su código de ejemplo -

/* 
* 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.pdfbox; 

import java.awt.HeadlessException; 
import java.awt.Toolkit; 
import java.awt.image.BufferedImage; 

import javax.imageio.ImageIO; 

import java.util.List; 

import org.apache.pdfbox.exceptions.InvalidPasswordException; 
import org.apache.pdfbox.pdmodel.PDDocument; 
import org.apache.pdfbox.pdmodel.PDPage; 
import org.apache.pdfbox.pdmodel.common.PDRectangle; 
import org.apache.pdfbox.util.PDFImageWriter; 

/** 
* Convert a PDF document to an image. 
* 
* @author <a href="ben@benlitchfield.com">Ben Litchfield</a> 
* @version $Revision: 1.6 $ 
*/ 
public class PDFToImage 
{ 

    private static final String PASSWORD = "-password"; 
    private static final String START_PAGE = "-startPage"; 
    private static final String END_PAGE = "-endPage"; 
    private static final String IMAGE_FORMAT = "-imageType"; 
    private static final String OUTPUT_PREFIX = "-outputPrefix"; 
    private static final String COLOR = "-color"; 
    private static final String RESOLUTION = "-resolution"; 
    private static final String CROPBOX = "-cropbox"; 

    /** 
    * private constructor. 
    */ 
    private PDFToImage() 
    { 
     //static class 
    } 

    /** 
    * Infamous main method. 
    * 
    * @param args Command line arguments, should be one and a reference to a file. 
    * 
    * @throws Exception If there is an error parsing the document. 
    */ 
    public static void main(String[] args) throws Exception 
    { 
     String password = ""; 
     String pdfFile = null; 
     String outputPrefix = null; 
     String imageFormat = "jpg"; 
     int startPage = 1; 
     int endPage = Integer.MAX_VALUE; 
     String color = "rgb"; 
     int resolution; 
    float cropBoxLowerLeftX = 0; 
    float cropBoxLowerLeftY = 0; 
    float cropBoxUpperRightX = 0; 
    float cropBoxUpperRightY = 0; 
     try 
     { 
      resolution = Toolkit.getDefaultToolkit().getScreenResolution(); 
     } 
     catch(HeadlessException e) 
     { 
      resolution = 96; 
     } 
     for(int i = 0; i < args.length; i++) 
     { 
      if(args[i].equals(PASSWORD)) 
      { 
       i++; 
       if(i >= args.length) 
       { 
        usage(); 
       } 
       password = args[i]; 
      } 
      else if(args[i].equals(START_PAGE)) 
      { 
       i++; 
       if(i >= args.length) 
       { 
        usage(); 
       } 
       startPage = Integer.parseInt(args[i]); 
      } 
      else if(args[i].equals(END_PAGE)) 
      { 
       i++; 
       if(i >= args.length) 
       { 
        usage(); 
       } 
       endPage = Integer.parseInt(args[i]); 
      } 
      else if(args[i].equals(IMAGE_FORMAT)) 
      { 
       i++; 
       imageFormat = args[i]; 
      } 
      else if(args[i].equals(OUTPUT_PREFIX)) 
      { 
       i++; 
       outputPrefix = args[i]; 
      } 
      else if(args[i].equals(COLOR)) 
      { 
       i++; 
       color = args[i]; 
      } 
      else if(args[i].equals(RESOLUTION)) 
      { 
       i++; 
       resolution = Integer.parseInt(args[i]); 
      } 
      else if(args[i].equals(CROPBOX)) 
      { 
       i++; 
      cropBoxLowerLeftX = Float.valueOf(args[i]).floatValue(); 
       i++; 
      cropBoxLowerLeftY = Float.valueOf(args[i]).floatValue(); 
       i++; 
      cropBoxUpperRightX = Float.valueOf(args[i]).floatValue(); 
       i++; 
      cropBoxUpperRightY = Float.valueOf(args[i]).floatValue(); 
      } 
      else 
      { 
       if(pdfFile == null) 
       { 
        pdfFile = args[i]; 
       } 
      } 
     } 
     if(pdfFile == null) 
     { 
      usage(); 
     } 
     else 
     { 
      if(outputPrefix == null) 
      { 
       outputPrefix = pdfFile.substring(0, pdfFile.lastIndexOf('.')); 
      } 

      PDDocument document = null; 
      try 
      { 
       document = PDDocument.load(pdfFile); 


       //document.print(); 
       if(document.isEncrypted()) 
       { 
        try 
        { 
         document.decrypt(password); 
        } 
        catch(InvalidPasswordException e) 
        { 
         if(args.length == 4)//they supplied the wrong password 
         { 
          System.err.println("Error: The supplied password is incorrect."); 
          System.exit(2); 
         } 
         else 
         { 
          //they didn't supply a password and the default of "" was wrong. 
          System.err.println("Error: The document is encrypted."); 
          usage(); 
         } 
        } 
       } 
       int imageType = 24; 
       if ("bilevel".equalsIgnoreCase(color)) 
       { 
        imageType = BufferedImage.TYPE_BYTE_BINARY; 
       } 
       else if ("indexed".equalsIgnoreCase(color)) 
       { 
        imageType = BufferedImage.TYPE_BYTE_INDEXED; 
       } 
       else if ("gray".equalsIgnoreCase(color)) 
       { 
        imageType = BufferedImage.TYPE_BYTE_GRAY; 
       } 
       else if ("rgb".equalsIgnoreCase(color)) 
       { 
        imageType = BufferedImage.TYPE_INT_RGB; 
       } 
       else if ("rgba".equalsIgnoreCase(color)) 
       { 
        imageType = BufferedImage.TYPE_INT_ARGB; 
       } 
       else 
       { 
        System.err.println("Error: the number of bits per pixel must be 1, 8 or 24."); 
        System.exit(2); 
       } 

       //si une cropBox a ete specifier, appeler la methode de modification de cropbox 
     //changeCropBoxes(PDDocument document,float a, float b, float c,float d) 
     if (cropBoxLowerLeftX!=0 || cropBoxLowerLeftY!=0 || cropBoxUpperRightX!=0 || cropBoxUpperRightY!=0) 
     { 
      changeCropBoxes(document,cropBoxLowerLeftX, cropBoxLowerLeftY, cropBoxUpperRightX, cropBoxUpperRightY); 
     } 

       //Make the call 
       PDFImageWriter imageWriter = new PDFImageWriter(); 
       boolean success = imageWriter.writeImage(document, imageFormat, password, 
         startPage, endPage, outputPrefix, imageType, resolution); 
       if (!success) 
       { 
        System.err.println("Error: no writer found for image format '" 
          + imageFormat + "'"); 
        System.exit(1); 
       } 
      } 
      catch (Exception e) 
      { 
       System.err.println(e); 
      } 
      finally 
      { 
       if(document != null) 
       { 
        document.close(); 
       } 
      } 
     } 
    } 

    /** 
    * This will print the usage requirements and exit. 
    */ 
    private static void usage() 
    { 
     System.err.println("Usage: java org.apache.pdfbox.PDFToImage [OPTIONS] <PDF file>\n" + 
      " -password <password>   Password to decrypt document\n" + 
      " -imageType <image type>  (" + getImageFormats() + ")\n" + 
      " -outputPrefix <output prefix> Filename prefix for image files\n" + 
      " -startPage <number>   The first page to start extraction(1 based)\n" + 
      " -endPage <number>    The last page to extract(inclusive)\n" + 
      " -color <string>    The color depth (valid: bilevel, indexed, gray, rgb, rgba)\n" + 
      " -resolution <number>   The bitmap resolution in dpi\n" + 
      " -cropbox <number> <number> <number> <number> The page area to export\n" + 
      " <PDF file>      The PDF document to use\n" 
      ); 
     System.exit(1); 
    } 

    private static String getImageFormats() 
    { 
     StringBuffer retval = new StringBuffer(); 
     String[] formats = ImageIO.getReaderFormatNames(); 
     for(int i = 0; i < formats.length; i++) 
     { 
      retval.append(formats[i]); 
      if(i + 1 < formats.length) 
      { 
       retval.append(","); 
      } 
     } 
     return retval.toString(); 
    } 

    private static void changeCropBoxes(PDDocument document,float a, float b, float c,float d) 
    { 
     List pages = document.getDocumentCatalog().getAllPages(); 
     for(int i = 0; i < pages.size(); i++) 
     { 
       System.out.println("resizing page"); 
      PDPage page = (PDPage)pages.get(i); 
      PDRectangle rectangle = new PDRectangle(); 
       rectangle.setLowerLeftX(a); 
       rectangle.setLowerLeftY(b); 
       rectangle.setUpperRightX(c); 
       rectangle.setUpperRightY(d); 
      page.setMediaBox(rectangle); 
      page.setCropBox(rectangle); 

     } 

    } 

} 

Answer 2

También podría tener una mira JPedal (detalles en http://www.jpedal.org/pdf_thumbnail.php)

Answer 3

IcePdf es lo mejor que he visto (que es gratis) para leer archivos PDF. JPedal es increíble, pero no gratis.

Si vas a generar imágenes de pdfs que el público en general puede enviarte, te aseguro (por experiencia) que obtendrás archivos PDF que bloquearán la JVM. (es decir: si son pdfs de muchas capas con todos los gráficos vectoriales). This pdf es un ejemplo que bloqueará muchas bibliotecas (pero es un PDF perfectamente válido sin nada gracioso como Javascript, etc.).

Hemos recorrido la ruta de intentar utilizar una gran cantidad de bibliotecas y, finalmente, recurrimos a delegar el trabajo de crear una miniatura en ImageMagick, que es un programa C altamente optimizado para la manipulación de imágenes.

Answer 4

This post no sólo es pdf, sino también muchos otros tipos de archivos como oficina, imagen, texto ....