I'm trying to replace a section of a PDF with different text. From research on all major PDF libraries for .NET, it seems this is complicated and not a trivial task. I think it may be easier to convert the PDF to an image, replace the text (always in the same place), then convert it back to a PDF (or leave it as an image if converting back isn't possible). Is it possible to extract an image from a PDF page with .NET?
If your text is in a known location, you can simply cover it with a rectangle filled with the background color, and then draw your text over top.
Note that the text will still be there, it simply won't be visible. Someone selecting text will still pick up the old stuff. If that's acceptable, it's quite trivial.
If the PDF was created from image, you can import it into Photoshop to edit it as an graphic. Or you can use screenshot program like "Snagit" to capture pdf page as image and use snagit's editor to erase old text and replace new one.
But this method may bring you problem is that the new added text may not the same font as text around it. Personally, I use pdf editor to replace text in pdf since the added text will be automatically fit with the original font and size.
Related
I'm looking for a way to get the result of an overlay between two pdf documents.
We have a document with a single page and only a header and another document with multiple pages and full content (header and body). We're looking for way to generate an overlay pdf between those documents, so that the resulting document with the content gets its header overwritten in each page with the single page document header. Basically like this:
Is there a opensource c# library, which can handle this and not convert the text to a picture.
I looked at PdfSharp and docnet, but couldn't figure it out with either of them.
So far we are using pdfbox, but we'd like to get rid of the java dependency.
Simple solution with PDFsharp: draw a white rectangle that hides the original header, then draw the new header on top of the rectangle.
Drawback: The old header is still contained in the document.
I need to enter a text to existing pdf (in top or bottom of the page) in c#.
I need to make sure that I dont overwrite any visible text or image.
Is there any way I could check an area in pdf if it contains text, image, control etc? I understand it will not be 100% accurate
You're going to need a full PDF consumer at the very least, because the only way to find out where the marks are on the page is to parse (and possibly render) the PDF.
There are complications which you haven't covered (possibly they have not occurred to you); what do you consider to be the area of the PDF file ? The MediaBox ? CropBox, TrimBox, ArtBox, BleedBox ? What if the PDF file contains, for example, a rectangular fill with white which covers the page ? What about a /Separation space called /White ? is that white (it generally gets rendered that way on the output) or not ? And yes, this is a widely used ink in the T-shirt printing industry amongst others.
To me the simplest solution would seem to be to use a tool which will give you the BoundingBox of marks on the page. I know the Ghostscript bbox device can do this, I imagine there are other tools which can do so. But note (for Ghostscript at least); if there are any marks in white (whatever the colour space), these are considered as marking the page and will be counted into the bbox.
The same tool ought to be able to give the size of the various Boxes in the PDF file (you'd need the pdf_info.ps program for Ghostscript to get this, currently). You can then quickly calculate which areas are unmarked.
But 'unmarked' isn't the same things as 'white'. If you want to not count areas which are painted in 'white' then the problem becomes greater. You really need to render the content and then look at each image sample in the output to see if its white or not, recording the maxima and minima of the x and y co-ordinates to determine the 'non-white' area of the page.
This is because there are complications like transfer functions, transparency blending, colour management, and image masking, any or all of which might cause an area which is marked with a non-white colour to be rendered white (a transparency SMask for example) or an area marked with white to be rendered non-white (eg a transfer function).
Your question is unclear because you haven't defined whether any of these issues are important to you, and how you want to treat them.
I have a client that is asking me to add a fixed width (510 character) header record to a PDF file. They have asked that I create a new page (not problem) in which I write this fixed width header record on.
I can do this, and see the header record as page 1, followed by the original PDF. The problem is white space. The 510 character fixed width header is about 60% white space and all the ways I've tried generating the PDF cause this to be truncated. There are also line breaks where the text wraps. The client want to be able to use some OCR software they have purchased in order to read this header file from page 1.
I know very little about PDF file format. I've tried using ABCpdf, PDFsharp, and also created an RDLC and bound it to this header string and then generated a PDF from that. All 3 resulted in the same outcome.
Let me say I know how crazy this sounds, but it's what a client is requesting. I proposed several other ways in which we could solve their problem, but this (right now) is the only one they are comfortable with. They are not comfortable with me just appending the 510 characters onto the byte array, and having them separate it out programatically.
Are you looking to have a page displaying the long header? You can create a PDF page of any size (Print to PDF with a custom pages size of 20" wide by 6" tall. Weird but possible.)
Once that page is created, it can be inserted into another document of regular letter size pages.
Are you looking for consecutive pages displaying chunks of the header?
Using an OCR to read content that you put in is an overkill. Instead of rendering the 500-character header as text. Render it as single-character form fields. This way it will be easy to access those form-fields by name and retrieve the values using the same PDF library which you created the PDFs.
I'm trying to generate a PDF via code because not all actual PDF .NET libraries support the new Windows Runtime for Windows/Windows Phone 8.1.
The PDF is saved correctly, with only a bug of stream position count that I can fix easily, but, as you can see, the text doesn't wrap if line is too long.
I tried with PDF NewLine char (\n), but C# automatically convert it in the input string
Also, I can't understand the position of lines or objects to put into the document, because I follow this guide online that talk about a reversing axis disposition (x for height and y for width), but seems I didn't catch the right methodology (I put in my code a constant left position, at 40, and a variable top descreasing value (from 600, I'm not manage now the multipage if the value is less than 0).
This is the code of PDF generated:
http://pastebin.com/ZkZmbJdM
(Sorry if I use Pastebin, but using this editor Code function the code seems to be unformatted for special characters used for it)
Where am I doing wrong?
PDF is a graphical format trying to make you think it's a document format. But nope, it's just like drawing with GDI+ for instance. This is the reason why it can achieve the same rendered output across many platforms/programs/etc as opposed to text flow formats like doc/docx. And also, this is why it can really render anything.
So, as opposed to document formats, it is the responsibility of the program that generates the PDF to get the layout right. Think of it just as if you'd draw with GDI+.
In documents like docx or html, it's the rendering program that has to do the layout work. With such document, you just write text and the viewer will take care of laying it out.
Your PDF library certainly has the necessary code to measure the text length. Maybe even it has some code to provide some layout capabilities. You'll have to use these functions to do the layout.
I have some RTF text. Sometimes text contain some images. Images is displayed inside any rtf editor, but i cannot get images positions programmatically.
I have used RichTextBox control for RTF parsing, but is unable to detect image positions inside text in RichTextBox control
So, does anybody know how to parse RTF and get images positions inside text programmatically using C#?
You might take a look at http://www.codeproject.com/KB/string/nrtftree.aspx it is open source and able to extract images, so I hope this helps.