How to find the used characters in a subsetted font? - pdf

I have PDF files which are dynamically generated, with text, vectors, and subsetted fonts. I can see which fonts are used in various viewers - is there a way of displaying the actual subsetted characters of those fonts?
For example, I see the document contains the subsetted subsetted fonts "AAAAAC+FreeMono" and "AAAAAD+DejaVuSans". How do I find how many characters were subsetted from these fonts, and what characters they were?
(I tried loading the fonts in FontForge, but it just crashes while opening the file)

The solution is to save the font data to a file and load it into a font editor. A subset font file is still a valid font file but it is possible that FontForge expects some data in the font that is not there. I have seen also many fonts that are not properly subset and this could also cause loading problems in a font editor.

Related

open a PDF file with automatically replaced Fonts

I am not a programmer, but a normal user who uses Linux.
I want to use Ghostscript to DISPLAY Pdf files, not to CREATE Pdf files. (I have never used Ghostscript until now).
But I want Ghostscript to automatically replace all fonts with other fonts when I open the PDF. No matter if the fonts are embedded or not.
With which fonts should the fonts be replaced?
Answer: I want to create a list of fonts, that I want to be available for replacement.
But which of these fonts on the list should be used?
Answer: The one that best matches the metric of the font to be replaced.
Is it possible to do this somehow?
You can't get Ghostscript to do what you are asking. If a PDF file contains fonts Ghostscript will use those fonts, it will only substitute if it cannot find an embedded font.
The reason for this is simple; the font embedded in the PDF file is the correct font. It's Metrics are correct, and the mapping form character code to the appropriate glyph selector in the font will be correct.
It's also a non-trivial problem to select from a list of fonts the one which 'best matches the metrics of the font to be replaced'. What characteristics should be considered ? How should those be determined ?
When a font is not embedded then Ghostscript will consult its own list of fonts and CIDFonts. Both of these lists can be customised, the documentation is here
But since a substitute font is always going to be a compromise, you can't tell Ghostscript not to use the embedded fonts in a PDF. Well technically you could, by modifying the PDF interpreter, but you say you aren't a programmer, so I doubt you will want to try that.

Which Chinese font is commonly supported by PDF readers of Chinese people?

I am generating PDF files which contain English and Chinese characters (using the Ruby Prawn library). I don't want to embed a Chinese font file in the generated PDF files, because these files need to stay small. So I'm wondering if I could just mentioning a Chinese font name in my PDF files, and have the PDF readers correctly rendering the Chinese characters because the PDF readers would already have the Chinese font file.
Is that something sensible? If so is there any commonly used Chinese font that one can expect to be installed in most of the PDF readers used by Chinese people?
The best way to ensure that a PDF file can be displayed on a any reader, is to use partially embedded fonts (also known as font subset). In PDF, you don't need to include the whole font with your document, having a subset with just the glyphs that were used in the file is enough for the file to be portable.

Copy text from PDF with custom FONT

I am trying to copy some text from a PDF. But When I paste it in a word file, it is just some garbage. Something like മുഖവുര. The PDF is in Malayalam language. When I see File->Properties->Fonts, It says BRHMalayalam (Embedded Subset) as shown in the screenshot.
I installed various Malayalam fonts but still no luck. Can anyone please guide me?
The PDF I am trying to copy from is https://drive.google.com/open?id=0B3QCwY9Vanoza0tBdFJjd295WEE&authuser=0
Installing fonts won't help, since they are embedded in the document. The reader will use the ones in the document.
In fact it almost certainly must use the ones on the document, because it will probably have used character codes specific to each font subset.
Your PDF probably has character codes which are not Unicode values, and does not contain ToUnicode CMaps for the fonts in question (note the same font name embedded multiple times). There is no realistic way to copy the text.
The best you can do is OCR it.
After looking at the file, and confirming the answer already given by #KenS, the problem with this PDF document is in fact how it's constructed. Or rather how the font in the document has been embedded.
The document contains a number of Times and Arial fonts, for which the text can be copied successfully. Those fonts are embedded as a subset with a WinAnsi encoding. What is actually in the file is close enough to that, that the text seems to copy out well.
The problem font (BRHMalayalam) is also embedded as a subset, and its encoding is also set as WinAnsiEncoding, which completely doesn't make sense.
And because the font doesn't contain a ToUnicode mapping table, a PDF viewer has no other choice when copying and pasting to assume the characters in the PDF are indeed Win Ansi encoding which means you end up with (garbled) latin characters.
Just convert the pdf file to word file and then edit or copy or modify the text present in the file simple :)
and after completion go to file -> save as -> and change the format of doc to pdf ..hope u understood :)

Possible to edit PDF without embedded font installed?

I have a PDF and need to edit its text.
It has an embedded font and I'm not able to find the font to install. Is it possible to edit the text and maintain its embedded font when I don't have the font installed?
I'm editing with Acrobat X and its warning me that I don't have the font and forcing me to change the font of the text I want to edit to one that I have installed. I've Googled for a couple hours and found the font family, but not the variation that's embedded. Because the font is already in the document, I would have thought Acrobat or another software program could tap it to allow me to edit, though I'm guessing I'm missing something.
It depends...
1.
Most likely, your embedded font is a subset of the full font. That means that it contains only these glyphs (shapes that represent printable characters) which were required as representations for characters used by the original PDF.
If your edit wants to insert a character that wasn't present in the original PDF, Acrobat (or any other editing method) has to use a different font. The font embedded in the PDF simply doesn't have glyph that is suitable for your edit!
Also, your subsetted font's name is not exactly like the full set font's name: it uses has a randomly composed 6 uppercase character prefix with a +-sign to build the used font name, like ABCXYZ+Arial.
You could employ the free (as in beer) Acrobat Plugin FontReporter to generate a list of all glyphs contained in your font.
You can also use this answer:
"How can I extract embedded fonts from a PDF as valid font files?"
to extract the font in question.
Then open the extracted font (which will be the subset variant, mind you!) in FontForgehttp://fontforge.github.io/en-US/), and there check two things:
the original font's license
the original font's creator
With that knowledge you could then definitely find the variant of the family that is embedded (or rather: that was present when the PDF generating and font embedding software created the subset).
2.
If the (subsetted) font you are looking at uses a so called "custom encoding", it may be almost impossible to edit the PDF file with standard tools (even if you have the same font locally installed that was used to create the PDF file).

How to replace or modify the font or glyphs embedded in a PDF file?

I want to replace the font embedded in an existing PDF file programmatically (with iText).
iText itself does not seem to provide any data model for glyphs and fonts, but I believe it can let me retrieve and update the binary stream that contains the font.
It's OK even if I don't know which glyph is associated to which font - what I want to do is just to replace them. To be precise, I want to embold all glyphs in a PDF document.
Replacing fonts in rendering time is not an option because the output must be PDF with all information preserved as is.
Is there anyone who has done this before with iText or any other PDF libraries?
PDF files define a set of fonts (ie F0, F1, F2) and then define these separately so you could theoretically rewrite the entry for F0. You would have to ensure the 2 fonts have the same spacing (or you will have to rewrite the PDF as well), and probably hack the PDF manually.