【JAVA】将PDF转化成图片

很多的开源库可以完成这个任务,但是效果都不理想,主要会产生以下问题:

1)分辨率很低,就是最后转化成的图片是缩略图,放大之后看不清楚;

2)不能支持中文,所有中文一律乱码;

3)图片各种混淆:大体是对的,但是个别元素出现混乱,尺寸位置不对等等;

上面说到的三种问题在各种类库中或多或少都存在。

A)实验下来效果最好的是QOPPA的开源库,在免费部分的测试情况下可以得到极为良好的效果。但是它最为不好的就是无条件加了水印,而且每行图片上面还加了网址,导致完全不可用了,而付费部分需要$400,实在买不起,所以虽然效果良好,但是还是不可行的。

B)再看ICEPDF这个开源库,这个库是最差的(也可能是我用的不好)

可以看到上面提到的问题1)和2)它全犯了!

C)再看PDFView这个开源库,转出效果如下:

怎么样,效果其实还可以的,对吧?但是问题是

1)分辨率低;2)背景么的了;

还有一个问题这张图片看不出来,我换一张:

插图无缘无故被放大了,遮住了文字,是问题3)。

D)再看JPEDAL开源库,这个库的普通转换效果如下:

这个不错吧,除了分辨率低,文字,背景全在,但是它也有上面的问题,插入的图片尺寸不对(这里就不展示了)

它最好的地方在于它还提供了高分辨率的转换,如下:

怎么样,够大够气派吧?超高分辨率,清晰的一米,剩下唯一的不好就是图片尺寸问题。

E)还有一个开源库叫PDFBox,还有PDFRender,这两个类库的问题都是分辨率不够高,PDFBox对中文的支持也存在很多问题,让人头疼。

我最后打算采用的方法就是D)的高分辨率转化方法。把测试代码展示如下:

1)转换类:

  1 /**
  2  * Example to convert PDF to highest possible quality images
  3  * Also consider org.jpedal.examples.images.ConvertPagesToImages for faster if quality less important
  4  *
  5  * Useful blog article at http://www.jpedal.org/PDFblog/2009/07/pdf-to-image-quality/
  6  *
  7  * It can run from jar directly using the command
  8  *
  9  * java -cp libraries_needed org/jpedal/examples/images/ConvertPagesToHiResImages pdfFilepath inputValues
 10  *
 11  * where inputValues is 2 values
 12  *
 13  * First Parameter:  The full path including the name and extension of the target PDF file.
 14  * Second Parameter:  The output image file type. Choices are tif, jpg and png.
 15  *
 16  * See also http://www.jpedal.org/javadoc/org/jpedal/constants/JPedalSettings.html for settings to customise
 17  */
 18 
 19 /**
 20  * ===========================================
 21  * Java Pdf Extraction Decoding Access Library
 22  * ===========================================
 23  *
 24  * Project Info:  http://www.jpedal.org
 25  * (C) Copyright 1997-2012, IDRsolutions and Contributors.
 26  *
 27  *   This file is part of JPedal
 28  *
 29      This source code is copyright IDRSolutions 2012
 30 
 31 
 32   *
 33   * ---------------
 34   * ConvertPagesToHiResImages.java
 35   * ---------------
 36  */
 37 
 38 import java.awt.Graphics2D;
 39 import java.awt.image.BufferedImage;
 40 import java.io.BufferedOutputStream;
 41 import java.io.File;
 42 import java.io.FileOutputStream;
 43 import java.io.IOException;
 44 import java.io.OutputStream;
 45 import java.util.*;
 46 
 47 import javax.imageio.IIOImage;
 48 import javax.imageio.ImageIO;
 49 import javax.imageio.ImageTypeSpecifier;
 50 import javax.imageio.metadata.IIOMetadata;
 51 import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
 52 import javax.imageio.stream.ImageOutputStream;
 53 
 54 import com.sun.imageio.plugins.jpeg.JPEGImageWriter;
 55 import org.jpedal.PdfDecoder;
 56 import org.jpedal.color.ColorSpaces;
 57 import org.jpedal.exception.PdfException;
 58 import org.jpedal.fonts.FontMappings;
 59 import org.jpedal.objects.PdfPageData;
 60 import org.jpedal.utils.LogWriter;
 61 import org.jpedal.io.ColorSpaceConvertor;
 62 import org.jpedal.io.JAIHelper;
 63 import org.jpedal.constants.JPedalSettings;
 64 import org.jpedal.constants.PageInfo;
 65 import org.w3c.dom.Element;
 66 
 67 public class ConvertPagesToHiResImages {
 68 
 69     private static boolean debug = false;
 70 
 71     /**correct separator for OS */
 72     final static String separator = System.getProperty( "file.separator" );
 73 
 74     //only used if between 0 and 1
 75     private float JPEGcompression=-1f;
 76 
 77     public ConvertPagesToHiResImages() {}
 78 
 79     public static void main(String[] args) throws Exception {
 80 
 81                  /*
 82         * Change these variables
 83         */
 84         String fileType,pdfFile;
 85 
 86         if(args!=null && args.length>1){
 87 
 88             pdfFile = args[0];
 89             fileType= args[1];
 90 
 91             //open the file
 92             if(pdfFile.toLowerCase().endsWith(".pdf") && (fileType.equals("jpg") || fileType.equals("jpeg") || fileType.equals("png") || fileType.equals("tiff") || fileType.equals("tif"))){
 93                 new ConvertPagesToHiResImages(fileType, pdfFile);
 94             }else{ //open the directory
 95 
 96                 File testDir=new File(pdfFile);
 97 
 98                 if(testDir.isDirectory()){
 99 
100                     /**
101                      * get list of files and check directory
102                      */
103 
104                     String[] files = null;
105                     File inputFiles;
106 
107                     /**make sure name ends with a deliminator for correct path later*/
108                     if (!pdfFile.endsWith(separator))
109                         pdfFile = pdfFile + separator;
110 
111                     try {
112                         inputFiles = new File(pdfFile);
113 
114                         files = inputFiles.list();
115                     } catch (Exception ee) {
116                         LogWriter.writeLog("Exception trying to access file " + ee.getMessage());
117                     }
118 
119                     /**now work through all pdf files*/
120                     for (String file : files) {
121 
122                         if (file.toLowerCase().endsWith(".pdf"))
123                             new ConvertPagesToHiResImages(fileType, pdfFile + file);
124                     }
125                 }else
126                     System.out.println("The file to be processed has to be a pdf and the output filetype can only be jpg,png or tiff");
127             }
128         }else{
129             System.out.println("Not enough arguments passed in! Usage: \"C:\\examples\\1.pdf\" \"jpg\"");
130         }
131     }
132 
133     /**
134      * main constructor to convert PDF to img
135      * @param fileType
136      * @param pdfFile
137      * @throws Exception
138      */
139     public ConvertPagesToHiResImages(String fileType, String pdfFile) throws Exception {
140 
141         long startTime=System.currentTimeMillis();
142 
143         String outputPath = pdfFile.substring(0, pdfFile.toLowerCase().indexOf(".pdf")) + separator;
144         File outputPathFile = new File(outputPath);
145         if (!outputPathFile.exists() || !outputPathFile.isDirectory()) {
146             if (!outputPathFile.mkdirs()) {
147                 if(debug)
148                     System.err.println("Can't create directory " + outputPath);
149             }
150         }
151 
152         //PdfDecoder object provides the conversion
153         final PdfDecoder decoder = new PdfDecoder(true);
154 
155         //mappings for non-embedded fonts to use
156 //        FontMappings.setFontReplacements();
157 
158         decoder.openPdfFile(pdfFile);
159 
160         /**
161          * this process is very flaxible to we create a Map and pass in values to select what sort
162          * of results we want. There is a choice between methods used and image size. Larger images use more
163          * memory and are slower but look better
164          */
165         Map mapValues = new HashMap();
166 
167         /** USEFUL OPTIONS*/
168         //do not scale above this figure
169         mapValues.put(JPedalSettings.EXTRACT_AT_BEST_QUALITY_MAXSCALING, 2);
170 
171         //alternatively secify a page size (aspect ratio preserved so will do best fit)
172         //set a page size (JPedal will put best fit to this)
173         mapValues.put(JPedalSettings.EXTRACT_AT_PAGE_SIZE, new String[]{"2000","1600"});
174 
175         //which takes priority (default is false)
176         mapValues.put(JPedalSettings.PAGE_SIZE_OVERRIDES_IMAGE, Boolean.TRUE);
177 
178         PdfDecoder.modifyJPedalParameters(mapValues);
179 
180         if(debug)
181             System.out.println("pdf : " + pdfFile);
182 
183         try{
184                          /**
185              * allow output to multiple images with different values on each
186              *
187              * Note we REMOVE shapes as it is a new feature and we do not want to break existing functions
188              */
189             String separation=System.getProperty("org.jpedal.separation");
190             if(separation!=null){
191 
192                 Object[] sepValues=new Object[]{7,"",Boolean.FALSE}; //default of normal
193                 if(separation.equals("all")){
194                     sepValues=new Object[]{PdfDecoder.RENDERIMAGES,"image_and_shapes",Boolean.FALSE,
195                             PdfDecoder.RENDERIMAGES + PdfDecoder.REMOVE_RENDERSHAPES,"image_without_shapes",Boolean.FALSE,
196                             PdfDecoder.RENDERTEXT,"text_and_shapes",Boolean.TRUE,
197                             7,"all",Boolean.FALSE,
198                             PdfDecoder.RENDERTEXT + PdfDecoder.REMOVE_RENDERSHAPES,"text_without_shapes",Boolean.TRUE
199                     };
200                 }
201 
202                 int sepCount =sepValues.length;
203                 for(int seps=0;seps<sepCount;seps=seps+3){
204 
205                     decoder.setRenderMode((Integer) sepValues[seps]);
206                     extractPageAsImage(fileType, outputPath, decoder,"_"+sepValues[seps+1], (Boolean) sepValues[seps + 2]); //boolean makes last transparent so we can see white text
207                 }
208 
209             }else //just get the page
210                 extractPageAsImage(fileType, outputPath, decoder,"",false);
211 
212         } finally {
213 
214             decoder.closePdfFile();
215         }
216         System.out.println("time="+(System.currentTimeMillis()-startTime)/1000);
217 
218 
219     }
220 
221     /**
222      * convenience method to get a page as a BufferedImage quickly
223      * - for bulk conversion, use the other methods
224      */
225     public static BufferedImage getHiresPage(int pageNo, int scaling, String pdfFile){
226 
227         BufferedImage imageToSave = null;
228 
229         final PdfDecoder decoder = new PdfDecoder(true);
230 
231         try{
232             //mappings for non-embedded fonts to use
233 //            FontMappings.setFontReplacements();
234 
235             decoder.openPdfFile(pdfFile);
236 
237             PdfPageData pageData = decoder.getPdfPageData();
238             int width=scaling*pageData.getCropBoxWidth(pageNo);
239             int height=scaling*pageData.getCropBoxHeight(pageNo);
240 
241             Map mapValues = new HashMap();
242 
243             /** USEFUL OPTIONS*/
244             //do not scale above this figure
245             mapValues.put(JPedalSettings.EXTRACT_AT_BEST_QUALITY_MAXSCALING, 2);
246 
247             //alternatively secify a page size (aspect ratio preserved so will do best fit)
248             //set a page size (JPedal will put best fit to this)
249             mapValues.put(JPedalSettings.EXTRACT_AT_PAGE_SIZE, new String[]{String.valueOf(width),String.valueOf(height)});
250 
251             //which takes priority (default is false)
252             mapValues.put(JPedalSettings.PAGE_SIZE_OVERRIDES_IMAGE, Boolean.TRUE);
253 
254             PdfDecoder.modifyJPedalParameters(mapValues);
255 
256             imageToSave = decoder.getPageAsHiRes(pageNo,null,false);
257 
258         } catch (PdfException e) {
259             e.printStackTrace();
260         } finally {
261 
262             decoder.closePdfFile();
263         }
264         return imageToSave;
265     }
266 
267     /**
268      * actual conversion of a PDF page into an image
269      * @param fileType
270      * @param outputPath
271      * @param decoder
272      * @param prefix
273      * @param isTransparent
274      * @throws PdfException
275      * @throws IOException
276      */
277     private void extractPageAsImage(String fileType, String outputPath, PdfDecoder decoder, String prefix, boolean isTransparent) throws PdfException, IOException {
278 
279 
280         //page range
281         int start=1, end=decoder.getPageCount();
282 
283         //container if the user is creating a multi-image tiff
284         BufferedImage[] multiPages = new BufferedImage[1 + (end-start)];
285 
286         /**
287          * set of JVM flags which allow user control on process
288          */
289 
290 
291         //////////////////TIFF OPTIONS/////////////////////////////////////////
292 
293         String multiPageFlag=System.getProperty("org.jpedal.multipage_tiff");
294         boolean isSingleOutputFile=multiPageFlag!=null && multiPageFlag.toLowerCase().equals("true");
295 
296         String tiffFlag=System.getProperty("org.jpedal.compress_tiff");
297         boolean compressTiffs = tiffFlag!=null && tiffFlag.toLowerCase().equals("true");
298 
299         //////////////////JPEG OPTIONS/////////////////////////////////////////
300 
301         //allow user to specify value
302         String rawJPEGComp=System.getProperty("org.jpedal.compression_jpeg");
303         if(rawJPEGComp!=null){
304             try{
305                 JPEGcompression=Float.parseFloat(rawJPEGComp);
306             }catch(Exception e){
307                 e.printStackTrace();
308             }
309             if(JPEGcompression<0 || JPEGcompression>1)
310                 throw new RuntimeException("Invalid value for JPEG compression - must be between 0 and 1");
311 
312         }
313 
314         String jpgFlag=System.getProperty("org.jpedal.jpeg_dpi");
315 
316         ///////////////////////////////////////////////////////////////////////
317 
318         for (int pageNo = start; pageNo < end+1; pageNo++) {
319 
320             if(debug)
321                 System.out.println("page : " + pageNo);
322 
323                          /**
324              * example1 - ask JPedal to return from decoding if file takes too long (time is in millis)
325              * will reset after exit so call for each page
326              */
327             //decoder.setPageDecodeStatus(DecodeStatus.Timeout,new Integer(20) );
328             /**
329              * example2 thread which will ask JPedal to time out and return from decoding
330              * will reset after exit so call for each page
331              */
332             /**
333              Thread a=new Thread(){
334              public void run() {
335 
336              while(true){
337              //simulate 2 second delay
338              try {
339              Thread.sleep(2000);
340              } catch (InterruptedException e) {
341              e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
342              }
343 
344              //tell JPedal to exit asap
345              decoder.setPageDecodeStatus(DecodeStatus.Timeout, Boolean.TRUE);
346 
347              }
348              }
349              };
350 
351              //simulate a second thread
352              a.start();
353 
354              //see code after line decoder.getPageAsHiRes(pageNo); for tracking whether JPedal timed out and returned
355              /**/
356 
357             /**
358              * If you are using decoder.getPageAsHiRes() after passing additional parameters into JPedal using the static method
359              * PdfDecoder.modifyJPedalParameters(), then getPageAsHiRes() wont necessarily be thread safe.  If you want to use
360              * getPageAsHiRes() and pass in additional parameters, in a thread safe mannor, please use the method
361              * getPageAsHiRes(int pageIndex, Map params) or getPageAsHiRes(int pageIndex, Map params, boolean isTransparent) and
362              * pass the additional parameters in directly to the getPageAsHiRes() method without calling PdfDecoder.modifyJPedalParameters()
363              * first.
364              *
365              * Please see org/jpedal/examples/images/ConvertPagesToImages.java.html for more details on how to use HiRes image conversion
366              */
367             BufferedImage imageToSave = decoder.getPageAsHiRes(pageNo,null,isTransparent);
368 
369             String imageFormat = System.getProperty("org.jpedal.imageType");
370             if(imageFormat!=null){
371                 if(isNumber(imageFormat)){
372                     int iFormat = Integer.parseInt(imageFormat);
373                     if(iFormat>-1 && iFormat<14){
374                         BufferedImage tempImage = new BufferedImage(imageToSave.getWidth(), imageToSave.getHeight(), iFormat);
375                         Graphics2D g = tempImage.createGraphics();
376                         g.drawImage(imageToSave, null, null);
377 
378                         imageToSave = tempImage;
379                     }else{
380                         System.err.println("Image Type is not valid. Value should be a digit between 0 - 13 based on the BufferedImage TYPE variables.");
381                     }
382                 }else{
383                     System.err.println("Image Type provided is not an Integer. Value should be a digit between 0 - 13 based on the BufferedImage TYPE variables.");
384                 }
385             }
386 
387             //show status flag
388             /**
389              if(decoder.getPageDecodeStatus(DecodeStatus.Timeout))
390              System.out.println("Timeout on decoding");
391              else
392              System.out.println("Done");
393              /**/
394 
395             decoder.flushObjectValues(true);
396 
397             //System.out.println("w="+imageToSave.getWidth()+" h="+imageToSave.getHeight());
398             //image needs to be sRGB for JPEG
399             if(fileType.equals("jpg"))
400                 imageToSave = ColorSpaceConvertor.convertToRGB(imageToSave);
401 
402 
403             String outputFileName;
404             if(isSingleOutputFile)
405                 outputFileName = outputPath+ "allPages"+prefix+ '.' + fileType;
406             else{
407                 /**
408                  * create a name with zeros for if more than 9 pages appears in correct order
409                  */
410                 String pageAsString=String.valueOf(pageNo);
411                 String maxPageSize=String.valueOf(end);
412                 int padding=maxPageSize.length()-pageAsString.length();
413                 for(int ii=0;ii<padding;ii++)
414                     pageAsString='0'+pageAsString;
415 
416                 outputFileName = outputPath + "page" + pageAsString +prefix + '.' + fileType;
417             }
418 
419                          //if just gray we can reduce memory usage by converting image to Grayscale
420 
421             /**
422              * see what Colorspaces used and reduce image if appropriate
423              * (only does Gray at present)
424              *
425              * Can return null value if not sure
426              */
427             Iterator colorspacesUsed=decoder.getPageInfo(PageInfo.COLORSPACES);
428 
429             int nextID;
430             boolean isGrayOnly=colorspacesUsed!=null; //assume true and disprove
431 
432             while(colorspacesUsed!=null && colorspacesUsed.hasNext()){
433                 nextID= (Integer) (colorspacesUsed.next());
434 
435                 if(nextID!= ColorSpaces.DeviceGray && nextID!=ColorSpaces.CalGray)
436                     isGrayOnly=false;
437             }
438 
439             //draw onto GRAY image to reduce colour depth
440             //(converts ARGB to gray)
441             if(isGrayOnly){
442                 BufferedImage image_to_save2=new BufferedImage(imageToSave.getWidth(),imageToSave.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
443                 image_to_save2.getGraphics().drawImage(imageToSave,0,0,null);
444                 imageToSave = image_to_save2;
445             }
446 
447             //put image in array if multi-images  (we save on last page in code below)
448             if(isSingleOutputFile)
449                 multiPages[pageNo-start] = imageToSave;
450 
451             //we save the image out here
452             if (imageToSave != null) {
453 
454                 /**BufferedImage does not support any dpi concept. A higher dpi can be created
455                  * using JAI to convert to a higher dpi image*/
456 
457                 //shrink the page to 50% with graphics2D transformation
458                 //- add your own parameters as needed
459                 //you may want to replace null with a hints object if you
460                 //want to fine tune quality.
461 
462                 /** example 1 biliniear scaling
463                  AffineTransform scale = new AffineTransform();
464                  scale.scale(.5, .5); //50% as a decimal
465                  AffineTransformOp scalingOp =new AffineTransformOp(scale, null);
466                  image_to_save =scalingOp.filter(image_to_save, null);
467 
468                  */
469 
470                 if(JAIHelper.isJAIused())
471                     JAIHelper.confirmJAIOnClasspath();
472 
473                 if(JAIHelper.isJAIused() && fileType.startsWith("tif")){
474 
475                     com.sun.media.jai.codec.TIFFEncodeParam params = new com.sun.media.jai.codec.TIFFEncodeParam();
476 
477                     if(compressTiffs)
478                         params.setCompression(com.sun.media.jai.codec.TIFFEncodeParam.COMPRESSION_PACKBITS);
479 
480                     if(!isSingleOutputFile){
481                         BufferedOutputStream os = new BufferedOutputStream(new FileOutputStream(outputFileName));
482 
483                         javax.media.jai.JAI.create("encode", imageToSave, os, "TIFF", params);
484                     }else if(isSingleOutputFile && pageNo == end){
485                         OutputStream out = new BufferedOutputStream(new FileOutputStream(outputFileName));
486                         com.sun.media.jai.codec.ImageEncoder encoder = com.sun.media.jai.codec.ImageCodec.createImageEncoder("TIFF", out, params);
487                         List vector = new ArrayList();
488                         vector.addAll(Arrays.asList(multiPages).subList(1, multiPages.length));
489 
490                         params.setExtraImages(vector.iterator());
491 
492                         encoder.encode(multiPages[0]);
493                         out.close();
494                     }
495                 }else if(isSingleOutputFile){
496                     //non-JAI
497                 } else if ((jpgFlag != null || rawJPEGComp!=null) && fileType.startsWith("jp") && JAIHelper.isJAIused()) {
498 
499                     saveAsJPEG(jpgFlag, imageToSave, JPEGcompression, new BufferedOutputStream(new FileOutputStream(outputFileName)));
500                 } else {
501 
502                     BufferedOutputStream bos= new BufferedOutputStream(new FileOutputStream(new File(outputFileName)));
503                     ImageIO.write(imageToSave, fileType, bos);
504                     bos.flush();
505                     bos.close();
506                 }
507                 //if you just want to save the image, use something like
508                 //javax.imageio.ImageIO.write((java.awt.image.RenderedImage)image_to_save,"png",new java.io.FileOutputStream(output_dir + page + image_name+".png"));
509 
510             }
511 
512             imageToSave.flush();
513 
514             if(debug){
515                 System.out.println("Created : " + outputFileName);
516 
517             }
518         }
519     }
520 
521     /**test to see if string or number*/
522     private static boolean isNumber(String value) {
523 
524         //assume true and see if proved wrong
525         boolean isNumber=true;
526 
527         int charCount=value.length();
528         for(int i=0;i<charCount;i++){
529             char c=value.charAt(i);
530             if((c<'0')|(c>'9')){
531                 isNumber=false;
532                 i=charCount;
533             }
534         }
535 
536         return isNumber;
537     }
538 
539     private static void saveAsJPEG(String jpgFlag,BufferedImage image_to_save, float JPEGcompression, BufferedOutputStream fos) throws IOException {
540 
541         //useful documentation at http://docs.oracle.com/javase/7/docs/api/javax/imageio/metadata/doc-files/jpeg_metadata.html
542         //useful example program at http://johnbokma.com/java/obtaining-image-metadata.html to output JPEG data
543 
544         //old jpeg class
545         //com.sun.image.codec.jpeg.JPEGImageEncoder jpegEncoder = com.sun.image.codec.jpeg.JPEGCodec.createJPEGEncoder(fos);
546         //com.sun.image.codec.jpeg.JPEGEncodeParam jpegEncodeParam = jpegEncoder.getDefaultJPEGEncodeParam(image_to_save);
547 
548         // Image writer
549         JPEGImageWriter imageWriter = (JPEGImageWriter) ImageIO.getImageWritersBySuffix("jpeg").next();
550         ImageOutputStream ios = ImageIO.createImageOutputStream(fos);
551         imageWriter.setOutput(ios);
552 
553         //and metadata
554         IIOMetadata imageMetaData = imageWriter.getDefaultImageMetadata(new ImageTypeSpecifier(image_to_save), null);
555 
556         if (jpgFlag != null){
557 
558             int dpi = 96;
559 
560             try {
561                 dpi = Integer.parseInt(jpgFlag);
562             } catch (Exception e) {
563                 e.printStackTrace();
564             }
565 
566             //old metadata
567             //jpegEncodeParam.setDensityUnit(com.sun.image.codec.jpeg.JPEGEncodeParam.DENSITY_UNIT_DOTS_INCH);
568             //jpegEncodeParam.setXDensity(dpi);
569             //jpegEncodeParam.setYDensity(dpi);
570 
571             //new metadata
572             Element tree = (Element) imageMetaData.getAsTree("javax_imageio_jpeg_image_1.0");
573             Element jfif = (Element)tree.getElementsByTagName("app0JFIF").item(0);
574             jfif.setAttribute("Xdensity", Integer.toString(dpi));
575             jfif.setAttribute("Ydensity", Integer.toString(dpi));
576 
577         }
578 
579         if(JPEGcompression>=0 && JPEGcompression<=1f){
580 
581             //old compression
582             //jpegEncodeParam.setQuality(JPEGcompression,false);
583 
584             // new Compression
585             JPEGImageWriteParam jpegParams = (JPEGImageWriteParam) imageWriter.getDefaultWriteParam();
586             jpegParams.setCompressionMode(JPEGImageWriteParam.MODE_EXPLICIT);
587             jpegParams.setCompressionQuality(JPEGcompression);
588 
589         }
590 
591         //old write and clean
592         //jpegEncoder.encode(image_to_save, jpegEncodeParam);
593 
594         //new Write and clean up
595         imageWriter.write(imageMetaData, new IIOImage(image_to_save, null, null), null);
596         ios.close();
597         imageWriter.dispose();
598 
599     }
600 }

2)测试类:

 1 public class Test {
 2 
 3     /**
 4      * @param args
 5      */
 6     public static void main(String[] args) {
 7         // TODO Auto-generated method stub
 8          try {
 9             ConvertPagesToHiResImages test =  new ConvertPagesToHiResImages("jpg", "/Users/mac/Desktop/pdftest/pdftest.pdf");
10         } catch (Exception e) {
11             // TODO Auto-generated catch block
12             e.printStackTrace();
13         }
14     }
15 
16 }

其余的代码就不贴了,要用的话网上也有,读者自己搜一下,然后我遇到的最大的问题就是jar包的下载,各种难找。

posted @ 2012-12-11 22:45 大脚印 阅读(...) 评论(...) 编辑 收藏