Adjusting format of PDF to print it faster - pdf

I am using a combination of iTextSharp and PdfSharp to assemble a large PDF file for printing to a Canon Oce VarioPrint 6000 series printer. The PDF is replacing a postscript file.
Both this new file and the old are transferred to the printer via an LPR command.
The postscript file would take maybe 10 minutes to rip to the printer. My PDF version of the same file is taking over 30 minutes to process before it is ready to print.
Can anyone give me pointers into ways I could change the way this file is written / created that would decrease the processing time on the Vario?
EDIT: I took the file that was ripping so slowly and ran it through Acrobat Preflight and it found many RGB images, that it wanted to convert to CMYK. When I look at the PDF though, they are all black and white logos, so I had Preflight do a fix up to convert all images to print Black and White.
I also noticed the Preflight was consolidating backgrounds. Half of the pages have the same logo on them, so leveraging this conversion is probably also helpful.
When I LPR'd that file, it copyed and ripped in less than 5 minutes! So I guess the real question is how can I do that programmatically?
I am modifying the title and tags.
Thanks!

An equivalent result to the preflight repair process in this case can be gotten by using iText (or in my case, iTextSharp). I replaced the PdfSharp method of aggregating the pdfs with the PdfSmartCopy class. This brought down the size of the outputted pdf significantly, combined with using iText's reader.RemoveUnusedObjects(), and my rip time to the printer was lowered to the same or below the previous rip times that we had with the postscript file. Very pleased.
So the RGB images that were probably contributing to the large processing time, were narrowed by the Smart copy removing duplicates.
More info on PdfSmartCopy can be found at: http://api.itextpdf.com/itext/com/itextpdf/text/pdf/PdfSmartCopy.html
and in Bruno's book, iText In Action, more specifically in Chapter 6.

Related

PDF Table Lines Missing from GhostScript

I am trying to convert a PDF file to an image format (ideally PNG), but some of the table lines do not render in the output, which is an issue since the purpose of my conversion is to use computer vision on it.
I unfortunately do not have access to the file used to generate the PDF.
Thank you in advance for your help!
Attached is the ghostscript rendering vs the actual pdf:
Original
GhostScript
EDIT: Thanks for the answers. Here is what I had already tried:- ---
Changing the scaling & Changing the Antialiasing (I doubt that any combination of this will work in Ghostscript at this point)
Converting to PostScript and then to PNG/PDF
Saving from a Browser
Saving from various virtual printers to PDF
Using Poppler to do the rendering
All to no avail. Digging deeper, I found some interesting things which may be helpfull. Ghostscript does recognize the lines when using -sDevice=X11 and -sDevice=PS2Write (apologies for coding typos). That is, using Ghostscript to visualize the PDF does work, but not to process them into anything else than Postscript.
Also, printing into a PDF from Adobe Acrobat does fix my problem, however this is something that I need to be able to do from the command line on thousands of files.
Hope this helps!
EDIT2:
Link to a concerned file
https://transfer.sh/PuIF90/e176ad9824ddc6cb5e6aead2d389c131-filer.pdf
I thought that I would share the fix that I found. Turns out that a bunch of the pdf we need to process were generated using a specific HTML5 to PDF conversion tool which turns each lines of the PDF into a rectangle with size 0. Solution for me has been to automate decompressing PDFs, and looking through the text file for "A A A A re", with all "A's" being numbers. Should the last or next to last A be a zero, I change it to size 1.
For instance (once again, after decompressing the PDF):
1000 2000 0 14 re
to
1000 2000 1 14 re
Hope this helps someone else out there and let me know if there is a more elegant way of doing this, I am still a beginner about all things PDF.

Issue with ghostscript rendering PPT into PDF

I've been tinkering with Ghostscript with a port monitor(on a HP PCL 6 Universal driver) to convert print job into PDF. I've tested with a few applications such as Words, Excel, Adobe Reader, Microsoft Edge etc and they are all working properly.
However upon testing Microsoft Powerpoint 2016, it seems like there are some graphics that are unable to be rendered properly through Ghostscript.
Actual Slide Below
Output From Ghostscript in PDF Below
I've tested this even with some other PDF generators such as BioPDF,CutePDF as well as AdobePDF and they would all result in the same output as above.
Just wondering has anyone tried and have faced similar issues before? if so could someone point me in the right direction??
What you are doing isn't a single step PowerPoint to PDF and Ghostscript is not rendering the PowerPoint. In fact if you are creating a PDF file Ghostscript isn't (ideally) rendering anything.
What's actually happening is that you are asking PowerPoint to print to a canvas, which is then passed to the PostScript printer driver. That produces PostScript which is sent to the Port. Your (and others) Port Monitor then sends the PostScript to the 'Distiller' (in your case Ghostscript and the pdfwrite device). The Distiller reformats the vector drawing commands into a PDF format and builds a PDF file from them. It doesn't render (turn into a bitmap image) anything unless forced to.
Obviously there are several places along that road where the problem could creep in. Given that you say that the Adobe product (the others you mention al use Ghostscript) has the same problem, I think its safe to assume that the problem isn't Ghostscript.
This also means that you aren't using the driver you think you are. Adobe can't handle PCL as an input medium as far as I'm aware, and nor can Ghostscript. GhostPCL will handle PCL as an input, but that's not what you say you are using.
Of course you haven't linked to an example file to demonstrate the problem, nor supplied an example command line, so this is all supposition.
Now if, somehow, you are using a PCL6 device, then the problem is most likely due to the presence of rasterOps in the output. Rasterops are part of the PCL imaging model which do not exist in PDF and are a form of transparency. There are three ways to handle such content for a PDF output device; firstly render the whole page content to an image, secondly ignore the rasterOps objects, thirdly treat the rasterOps as opaque.
GhostPCL and the pdfwrite device take the third option. So, its just conceivable that your original content has some transparent objects which are being handled as rasterOps by the PCL printer driver, and then rendered as opaque by GhostPCL and the pdfwrite device.
If that's somehow the case then the solution is simple; don't use a PCL printer driver, use the PostScript one.
If you post a link to a (simple, eg single page) example of what you are sending to Ghostscript, and a command line, then I can look at it. Please don't send me the PowerPoint, I can't use it and even if I could, my print setup would not match yours. I need the data being sent to Ghostscript.
[EDIT after looking at files]
Don't mean to sound like I'm lecturing, the problem is people find these result on Google searches and then try to apply them based on a poor understanding of what's happening. So I find it best to be really clear in my answers about what's going on. It saves questions later :-)
The first thing I see is that the PCL is indeed PCL, and if you try running that through Ghostscript it throws horrible errors and exits. So presumably you aren't doing that.
The PostScript file contains nothing except huge images, rendered (presumably at 600 dpi) contains 2 pages, the two pages look like your images above. Which is why the PostScript is better than 20 times larger than the PCL file.
But.... If I open the .ppt file with OpenOffice (4.0.0 is what I have to hand) I see exactly the same thing. I don't, I'm afraid, have a copy of Microsoft PowerPoint, but from what I see here there are two conclusions;
firstly that the PDF I get looks pretty much like the PowerPoint when viewed with OpenOffice at least. So there's something 'interesting' about your PowerPoint.
secondly, even if that's not what you expect, its what's in the PostScript program. That means that either PowerPoint rendered the slide to a bitmap or the Windows printing system/HP driver did.
Now, if I run the PCL through GhostPCL instead of Ghostscript (rendering, not producing a PDF) then the result is more like what I think you are expecting. However, when sent to a PDF file the result is horrible. Which strongly suggests to me that there's some form of transparency involved, PostScript doesn't support transparency at all, and PCL does it through rasterOPs.
I'm afraid that this means that the problem lies either in PowerPoint, the Windows print system or the PostScript printer driver you are using. Since the PCL is at least close to what you expect, I suspect that this means PowerPoint is doing the right thing, and its the printer driver messing up. It appears you are using the Windows PostScript printer driver.
So there's no way you can 'fix' this for files like this, at least not with Ghostscript. You would need to 'fix' the Windows PostScript printer driver, or possibly the Windows print system. You could try reporting a bug to Microsoft, presumably these files print incorrectly when sent to physical PostScript printers too.

Multipage background in PDF, using pdftk or other tool

How to add multipage background (eg. odd and even backgrounds) to 10 thousands pages PDF, with keeping output file as small as possible?
I'm doing massively multipage documents (eg. 10000 pages in one document). Each page has background, which I apply in such way:
I have lot of .dvi documents, I join them using dviconcat
next I do dvipdf on joined .dvi
and next I use pdftk to apply background, using pdftk infile.pdf background bg.pdf output outfile.pdf
In this way, I have fairly small file, eg. 200MB, comparing to situation when I produce lot of .pdf files with background and join them using pdftk and resulting file is eg. 2G.
I think it's because background is not repeated every page, but it's copy is stored in PDF only once and there is some kind of reference in pages.
Unfortunately, now I need to use 2pages / 2 sides background. Different background for odd pages and different for even. PDFtk don't know how to do it. I can prepare 10.000 pages background, but it will be huge (eg. 1G).
Any suggestion how could I accomplish it, without playing with multi-gigabytes files? Is it doable at all? If yes - with pdftk or some different tool?
One solution would be to do the background when you convert PostScript to PDF. Using a BeginPage procedure you can paint the background before you pain the page contents. By checking the page count in BeginPage you can choose which background to paint, so you can have different ones for even/odd/whatever pages.
If you specify each background as a PostScript form, then your BeginPage can be small, also (and rather more importantly) the current version of Ghostscript, 9.14, will attempt to pass PostScript forms into a PDF file as a PDF form,and it can identify and consolidate duplicates so it 'should' only embed each form once. This should result in the minimum possible file size.
However, this code is at an early stage of development and might not work for you, also you'll need to do some PostScript programming.
I'm not familiar with pdftk, but would it be possible to produce all the even page, add a background to them. Produce all the odd pages, add a different background, then use pdftk to merge and interleave the pages ?
NB Ghostscript doesn't handle .dvi files, so I'm rather at a loss to know how you use Ghostscript to 'join' them. Also, if you are somehow creating the PostScript files using Ghostscript, you would almost certainly be better off using Ghostscript to produce the PDF file directly. (I'm assuming here that you are using Ghostscript's ps2pdf, but even if you aren't it'll still be quicker to produce the PDF in one step, and almost certainly produce better output too)

PDF Compression and editing techniques

I am not sure this question belongs on a programming forum but then again not sure where it would.
I currently open any PDF documents in Adobe Acrobat 9 Pro when reading or editing files. Many times, I want to make a change to the text in those files and will simply use the Tools->Advanced Editing->Touch Up Text Tool to do so.
No issues with the actual text changes but when I go back to save the file, the file size increases drastically. Even after running Advanced->PDF Optimizer and Document->Reduce File Size, the size is still much larger than the previous file, in many cases even if I am reducing the amount of text on that page.
It is quite frustrating. I am sure entire books have been written about proper PDF compression but take one text only document I have for example: file size is 110KB for a 12 page document. We just migrated to Google Apps and an entire 72 page PDF was under 600 KB.
Am I missing something?
Save as... your document after some changes.
Sounds like the font data is being embedded into the PDF when you edit it. Run Acrobat's Space Audit on the original and modified PDF to determine what is taking up the extra space in the modified PDF.

PDF compression How does Adobe do it?

This is a bit more of a fun question than a serious one, but how does the Adobe PDF format make documents so... portable?
I just created a small Word document, 235kb in size, containing multiple color photos and a few textual phrases. A PDF created using CutePDF (which I understand isn't the most efficient method of PDF creation) is only 176kb. That's a 25% compression ratio. When those files are placed into a compressed folder, the PDF is capable of 3% compression where the .docx can only take 2%. I'm sure that larger files would have even greater differences in size.
My question is, how does Adobe manage to make their files so much smaller? I understand that they are drawn from raster graphics, but my 3 bitmap files really can't be helped from raster that much, can they?
If you have Acrobat 9 there is a nice tool built-in so you can see how the PDF was put together (and compressions used). There is a blog post explaining how to use it at http://pdf.jpedal.org/java-pdf-blog/bid/10479/Viewing-PDF-objects
There are a few ways it can be compressing this:
Pdf files use lzw and zip compression.
If the image is scaled in the document, or is a larger dpi on disk than you allow for in cutepdf (for example, if cutepdf is set for 300dpi and the image is 600 dpi), it can be scaled in the pdf.
Microsoft stores TONS of info in the docx format, in xml. WAY more than is really needed to just export the info (for an example, try copying and pasting your text into a textbox cell, and look at the html info that comes out - I had a limit on a textbox size for a cms, and a 7 word sentence ballooned to 950 characters). This is so it can be later edited, and with a lot of esoteric info to make sure everything displays right in every possible permutation. The pdf doesn't need that info, and so it can just do the font and size, and strip out all the unnecessary info, saving a ton of space.
When you use such small files any overhead in the document format will have a disproportionate effect which is why you are seeing such large % differences.
I took a 2683KB JPEG and inserted it into a new word 2003 document. The resulting .doc file was 2725KB (or 2697KB as docx). Turning this into a PDF gives me a 2701KB PDF. So I am seeing a difference of 25KB, but only about 1% difference because of the size of the image data. It is about half what you got but maybe the version of word you have is more verbose when making docx?
For the PDF, acrobat shows space usage as 2691K image, 8.27K overhead and 1K fonts. PDF is quite a sparse format in its syntax which limits overhead and much of it has repeating strings so is easily compressible.
If you want to see what the PDF contains in a tree-like view you can download the demo version of CosEdit.