PDF 竖切合并

Question

I have a booklet pdf. I want to Split in half ie Vertical + Re-paginate from booklet scan

Ex: booklet pages would be 1, 8 and 7, 2 etc.,

After processing i want to have a PDF with 1, 2, 3, 4, ....

Please advise which PDF library would be able to do the above in java

Thanks

Answer 1

Depending on how the booklet was scanned into the PDF, I think you might be able to do this using a Java library that can extract and merge PDF pages.

For example, in the LEADTOOLS Java PDF Library , which is what I am familiar with since I work for the vendor, there is a PDFFile class that can be used to extract and merge pages from and to a PDF file.

PDFFile file = new PDFFile(bookletFile);
int pageCount = file.getPageCount();
for (int i = 1; i <= pageCount; i++)
{
   File destinationFile =  new File(destinationFolder, String.format("Extracted_Page{0}.pdf", i));
   file.extractPages(i, i, destinationFile.getPath());
}

Since the booklet looks like it's scanned in a way that every other page will contain a double page. To split them, you can load every other extracted page as a raster image then use the library's raster imaging classes to save each half as a separate raster PDF:

RasterCodecs codecs = new RasterCodecs();
RasterImage firstHalfImage = codecs.load(extractedDoublePage);

// Create a LeadRect that encompasses the second half
LeadRect secondHalfLeadRect = new LeadRect(firstHalfImage.getImageWidth() / 2, 0, firstHalfImage.getImageWidth() / 2, firstHalfImage.getImageHeight());
// Create a new image containing the second half
RasterImage secondHalfImage = firstHalfImage.clone(secondHalfLeadRect);

// Crop First Image to contain only first half
LeadRect firstHalfLeadRect = new LeadRect(0, 0, firstHalfImage.getImageWidth() / 2, firstHalfImage.getImageHeight());
CropCommand cropCommand = new CropCommand(firstHalfLeadRect);
cropCommand.run(firstHalfImage);

You can then use the RasterCodecs.Save() method to save each image as a raster PDF file.

Finally, once you have split everything accordingly, you can use the PDFFile.MergeWith() method to combine all the pages back into one file in the needed order.