Chapter 11
Document Information and Metadata

cpdf -info [-raw | -utf8] in.pdf

cpdf -page-info in.pdf

cpdf -pages in.pdf

cpdf -set-title <title of document>
     [-also-set-xmp] [-just-set-xmp] [-raw] in.pdf -o out.pdf
(Also -set-author etc. See Section 11.2.)

cpdf -set-page-layout <layout> in.pdf -o out.pdf

cpdf -set-page-mode <mode> in.pdf -o out.pdf
cpdf -set-non-full-screen-page-mode <mode> in.pdf -o out.pdf

cpdf -hide-toolbar <true | false> in.pdf -o out.pdf

cpdf -open-at-page <page number> in.pdf -o out.pdf
cpdf -open-at-page-fit <page number> in.pdf -o out.pdf
cpdf -open-at-page-custom <destination> in.pdf -o out.pdf

cpdf -set-metadata <metadata-file> in.pdf -o out.pdfcpdf -remove-metadata in.pdf -o out.pdf
cpdf -print-metadata in.pdf
cpdf -create-metadata in.pdf -o out.pdf
cpdf -set-metadata-date <date> in.pdf -o out.pdf

cpdf -add-page-labels in.pdf -o out.pdf
     [-label-style <style>] [-label-prefix <string>]
     [-label-startval <integer>] [-labels-progress]

cpdf -remove-page-labels in.pdf -o out.pdf
cpdf -print-page-labels in.pdf

cpdf -composition in.pdf
cpdf -composition-json in.pdf

11.1 Reading Document Information

The -info operation prints entries from the document information dictionary, and from any XMP metadata to standard output.

$cpdf -info pdf_reference.pdf  
Encryption: 40bit  
Linearized: true  
Permissions: No edit  
Version: 1.6  
Pages: 1310  
Title: PDF Reference, version 1.7  
Author: Adobe Systems Incorporated  
Subject: Adobe Portable Document Format (PDF)  
Creator: FrameMaker 7.2  
Producer: Acrobat Distiller 7.0.5 (Windows)  
Created: D:20061017081020Z  
Modified: D:20061118211043-0230  
Trapped: False  
PageMode: UseOutlines  
XMP pdf:Producer: Adobe PDF library 7.77  
XMP xmp:CreateDate: 2006-12-21T18:19:09+01:00  
XMP xmp:CreatorTool: Adobe Illustrator CS2  
XMP xmp:MetadataDate: 2006-12-21T18:19:09Z  
XMP xmp:ModifyDate: 2006-12-21T18:19:09Z  
XMP dc:title: AI6

The details of the format for creation and modification dates can be found in Appendix A.

By default, cpdf strips to ASCII, discarding character codes in excess of 127. In order to preserve the original unicode, add the -utf8 option. To disable all postprocessing of the string, add -raw. See Section 1.17 for more information.

The -page-info operation prints the page label, media box and other boxes page-by-page to standard output, for all pages in the current range.

$cpdf -page-info 14psfonts.pdf  
Page 1:  
Label: i  
MediaBox: 0.000000 0.000000 600.000000 450.000000  
CropBox: 200.000000 200.000000 500.000000 500.000000  
Rotation: 0

Note that the format for boxes is minimum x, minimum y, maximum x, maximum y.

The -pages operation prints the number of pages in the file.

cpdf -pages Archos.pdf  

11.2 Setting Document Information

The document information dictionary in a PDF file specifies various pieces of information about a PDF. These can be consulted in a PDF viewer (for instance, Acrobat).

Here is a summary of the commands for setting entries in the document information dictionary:

Information        Examplecomm and-lin efragment
Title              cpdf -set-title

(The details of the format for creation and modification dates can be found in Appendix A. Using the date "now" uses the time and date at which the command is executed. Note also that -producer and -creator may be used to set the producer and/or the creator when writing any file, separate from the operations described in this chapter.)

For example, to set the title, the full command line would be

cpdf -set-title "A Night in London" in.pdf -o out.pdf

The text string is considered to be in UTF8 format, unless the -raw option is added—in which case, it is unprocessed, save for the replacement of any octal escape sequence such as \017, which is replaced by a character of its value (here, 15).

To set also any field in the XMP metadata, add -also-set-xmp. The field must exist already. To set only the field (not the document information dictionary), add -just-set-xmp instead.

To delete existing non-XMP metadata in line with PDF 2.0, use -remove-dict-entry "/Info" as described in chapter 19.

11.3 XMP Metadata

PDF files can contain a piece of arbitrary metadata, often in XMP format. This is typically stored in an uncompressed stream, so that other applications can read it without having to decode the whole PDF. To set the metadata:

cpdf -set-metadata data.xml in.pdf -o out.pdf

To remove any metadata:

cpdf -remove-metadata in.pdf -o out.pdf

To print the current metadata to standard output:

cpdf -print-metadata in.pdf

To create XMP metadata from scratch, using any information in the Document Information Dictionary (old-style metadata):

cpdf -create-metadata in.pdf -o out.pdf

To set the XMP metadata date field, use:

cpdf -set-metadata-date <date> in.pdf -o out.pdf

The date format is defined in Appendix A.2. Using the date "now" uses the time and date at which the command is executed.

11.4 Upon Opening a Document

11.4.1 Page Layout

The -set-page-layout operation specifies the page layout to be used when a document is opened in, for instance, Acrobat. The possible (case-sensitive) values are:

SinglePage      D isplay onepageatatim e
OneColumn       D isplay thep agesinonecolumn

TwoColumnLeft   D isplay the pages in tw o colum ns, odd num bered pages
                on the left
TwoColumnRight  Donispthlaeylethn pagesintwo columns,evennum beredpages
                (PDF 1.5and above)Displaythepagestwoatatime,odd
TwoPageLeft     num bered pageson the left

TwoPageRight    (PDF 1.5andabove)Displaythepagestw oatatime,even
                num bered pageson the left

For instance:

cpdf -set-page-layout TwoColumnRight in.pdf -o out.pdf

NB: If the file has a valid /OpenAction setting, which tells the PDF reader to open at a certain page or position on a page, this will override the page layout option. To prevent this, use the -remove-dict-entry functionality from Section 19.9:

cpdf -remove-dict-entry /OpenAction in.pdf -o out.pdf

11.4.2 Page Mode

The page mode in a PDF file defines how a viewer should display the document when first opened. The possible (case-sensitive) values are:

UseNone         N either docum entoutlinenor thum bnailim ages visible
UseOutlines     D ocum entoutline (bookmarks)visible

UseThumbs       Thum bnailimagesvisible
                Full-screenm ode(no menubar,windowcontrols,orany-
FullScreen      thing butthe docum entvisible)
UseOC           (PDF 1.5andabove)Optionalcontentgrouppanelvisible

UseAttachments  (PDF 1.5and above)Attachm entspanelvisible

For instance:

cpdf -set-page-mode FullScreen in.pdf -o out.pdf

If full screen mode is selected for document opening, we can also set a mode to be used when the user exits from full-screen mode:

cpdf -set-non-full-screen-page-mode UseAttachments in.pdf -o out.pdf

As would be expected, FullScreen is not allowed here.

11.4.3 Display Options

-hide-toolbar       H ide the viewer’stoolbar
-hide-menubar       D ocumentoutline (bookmarks)visible
-hide-window-ui     H ide the viewer’sscrollbars

-fit-window         R esizethe docum ent’swindowstofitsize offirstpage
-center-window      P ositionthedocumentwindow in thecenterofthescreen
                    D isplay the docum enttitleinsteadofthefilenameinthe
-display-doc-title  titlebar

For instance:

cpdf -hide-toolbar true in.pdf -o out.pdf

The page a PDF file opens at can be set using -open-at-page:

cpdf -open-at-page 15 in.pdf -o out.pdf

To have that page scaled to fit the window in the viewer, use -open-at-page-fit instead:

cpdf -open-at-page-fit end in.pdf -o out.pdf

(Here, we used end to open at the last page. Any page specification describing a single page is ok here.)

Alternatively, we may specify a full destination, of the kind described on page 41:

cpdf -open-at-page-custom "[3 /FitR 100 100 300 300]" in.pdf -o out.pdf

11.5 Page Labels

It is possible to add page labels to a document. These are not the printed on the page, but may be displayed alongside thumbnails or in print dialogue boxes by PDF readers. We use -add-page-labels to do this, by default with decimal arabic numbers (1,2,3…). We can add -label-style to choose what type of labels to add from these kinds:

    DecimalArabic  1,2,3,4,5...
   LowercaseRoman  i,ii,iii,iv,v...
   UppercaseRoman  I,II,III,IV,V...
 LowercaseLetters  a,b,c,...,z,aa,bb...
 UppercaseLetters  A ,B,C,...,Z,AA,BB...
NoLabelPrefixOnly  N onum ber,butaprefixwillbe used ifdefined.

We can use -label-prefix to add a textual prefix to each label. Consider a file with twenty pages and no current page labels (a PDF reader will assume 1,2,3…if there are none). We will add the following page labels:

i, ii, iii, iv, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, A-0, A-1, A-2, A-3, A-4, A-5

Here are the commands, in order:

cpdf -add-page-labels in.pdf 1-4 -label-style LowercaseRoman
     -o out.pdf

cpdf -add-page-labels out.pdf 5-14 -o out2.pdf

cpdf -add-page-labels out2.pdf 15-20 -label-prefix "A-"
     -label-startval 0 -o out3.pdf

By default the labels begin at page number 1 for each range. To override this, we can use -label-startval (we used 0 in the final command), where we want the numbers to begin at zero rather than one. The option -labels-progress can be added to make sure the start value progresses between sub-ranges when the page range specified is disjoint, e.g 1-9, 30-40 or odd.

Page labels may be removed altogether by using -remove-page-labels command. To print the page labels from an existing file, use -print-page-labels. For example:

$ cpdf -print-page-labels cpdfmanual.pdf  
labelstyle: LowercaseRoman  
labelprefix: None  
startpage: 1  
startvalue: 1  
labelstyle: DecimalArabic  
labelprefix: None  
startpage: 9  
startvalue: 1

11.6 Composition of a PDF

The -composition and -composition-json operations show how much space in a PDF is used by each kind of data. Here is the output of -composition for this manual:

$ cpdf -composition cpdfmanual.pdf  
Images: 0 bytes (0.00%)  
Fonts: 144731 bytes (46.72%)  
Content streams: 132767 bytes (42.85%)  
Structure Info: 0 bytes (0.00%)  
Attached Files: 0 bytes (0.00%)  
XRef Table: 21082 bytes (6.80%)  
Unclassified: 11229 bytes (3.62%)

And here it is in JSON format:

$ cpdf -composition-json cpdfmanual.pdf  
  ("Images", 0, 0.0),  
  ("Fonts", 144731, 46.71620256351494),  
  ("Content streams", 132767, 42.854468398271194),  
  ("Structure Info", 0, 0.0),  
  ("Attached Files", 0, 0.0),  
  ("XRef Table", 21082, 6.8048378194306816),  
  ("Unclassified", 11229, 3.6244912187831857)  

Note that, due to small inaccuracies in the method, it is possible for the Unclassified number to be negative.