11 Document Information and Metadata

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

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.

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:

(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.)

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.

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:

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:

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 18.9:

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:

11.4.3 Display Options

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

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

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:

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:

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:

C Interface

/* CHAPTER 11. Document Information and Metadata */

/*
* cpdf_isLinearized(filename) finds out if a document is linearized as
* quickly as possible without loading it.
*/
int cpdf_isLinearized(const char[]);

/* cpdf_getVersion(pdf) returns the minor version number of a document. */
int cpdf_getVersion(int);

/* cpdf_getMajorVersion(pdf) returns the minor version number of a document. */
int cpdf_getMajorVersion(int);

/* cpdf_getTitle(pdf) returns the title of a document. */
char *cpdf_getTitle(int);

/* cpdf_getAuthor(pdf) returns the author of a document. */
char *cpdf_getAuthor(int);

/* cpdf_getSubject(pdf) returns the subject of a document. */
char *cpdf_getSubject(int);

/* cpdf_getKeywords(pdf) returns the keywords of a document. */
char *cpdf_getKeywords(int);

/* cpdf_getCreator(pdf) returns the creator of a document. */
char *cpdf_getCreator(int);

/* cpdf_getProducer(pdf) returns the producer of a document. */
char *cpdf_getProducer(int);

/* cpdf_getCreationDate(pdf) returns the creation date of a document. */
char *cpdf_getCreationDate(int);

/* cpdf_getModificationDate(pdf) returns the modification date of a document. */
char *cpdf_getModificationDate(int);

/* cpdf_getTitleXMP(pdf) returns the XMP title of a document. */
char *cpdf_getTitleXMP(int);

/* cpdf_getAuthorXMP(pdf) returns the XMP author of a document. */
char *cpdf_getAuthorXMP(int);

/* cpdf_getSubjectXMP(pdf) returns the XMP subject of a document. */
char *cpdf_getSubjectXMP(int);

/* cpdf_getKeywordsXMP(pdf) returns the XMP keywords of a document. */
char *cpdf_getKeywordsXMP(int);

/* cpdf_getCreatorXMP(pdf) returns the XMP creator of a document. */
char *cpdf_getCreatorXMP(int);

/* cpdf_getProducerXMP(pdf) returns the XMP producer of a document. */
char *cpdf_getProducerXMP(int);

/* cpdf_getCreationDateXMP(pdf) returns the XMP creation date of a document. */
char *cpdf_getCreationDateXMP(int);

/*
* cpdf_getModificationDateXMP(pdf) returns the XMP modification date of a
* document.
*/
char *cpdf_getModificationDateXMP(int);

/* cpdf_setTitle(pdf) sets the title of a document. */
void cpdf_setTitle(int, const char[]);

/* cpdf_setAuthor(pdf) sets the author of a document. */
void cpdf_setAuthor(int, const char[]);

/* cpdf_setSubject(pdf) sets the subject of a document. */
void cpdf_setSubject(int, const char[]);

/* cpdf_setKeywords(pdf) sets the keywords of a document. */
void cpdf_setKeywords(int, const char[]);

/* cpdf_setCreator(pdf) sets the creator of a document. */
void cpdf_setCreator(int, const char[]);

/* cpdf_setProducer(pdf) sets the producer of a document. */
void cpdf_setProducer(int, const char[]);

/* cpdf_setCreationDate(pdf) sets the creation date of a document. */
void cpdf_setCreationDate(int, const char[]);

/* cpdf_setModificationDate(pdf) sets the modifcation date of a document. */
void cpdf_setModificationDate(int, const char[]);

/* cpdf_setTitleXMP(pdf) set the XMP title of a document. */
void cpdf_setTitleXMP(int, const char[]);

/* cpdf_setAuthorXMP(pdf) set the XMP author of a document. */
void cpdf_setAuthorXMP(int, const char[]);

/* cpdf_setSubjectXMP(pdf) set the XMP subject of a document. */
void cpdf_setSubjectXMP(int, const char[]);

/* cpdf_setKeywordsXMP(pdf) set the XMP keywords of a document. */
void cpdf_setKeywordsXMP(int, const char[]);

/* cpdf_setCreatorXMP(pdf) set the XMP creator of a document. */
void cpdf_setCreatorXMP(int, const char[]);

/* cpdf_setProducerXMP(pdf) set the XMP producer of a document. */
void cpdf_setProducerXMP(int, const char[]);

/* cpdf_setCreationDateXMP(pdf) set the XMP creation date of a document. */
void cpdf_setCreationDateXMP(int, const char[]);

/*
* cpdf_setModificationDateXMP(pdf) set the XMP modification date of a
* document.
*/
void cpdf_setModificationDateXMP(int, const char[]);

/*
* Dates: Month 1-31, day 1-31, hours (0-23), minutes (0-59), seconds (0-59),
* hour_offset is the offset from UT in hours (-23 to 23); minute_offset is
* the offset from UT in minutes (-59 to 59).
*/

/*
* cpdf_getDateComponents(datestring, year, month, day, hour, minute, second,
* hour_offset, minute_offset) returns the components from a PDF date string.
*/
void cpdf_getDateComponents(const char[], int *, int *, int *, int *, int *,
                            int *, int *, int *);

/*
* cpdf_dateStringOfComponents(year, month, day, hour, minute, second,
* hour_offset, minute_offset) builds a PDF date string from individual
* components.
*/
char *cpdf_dateStringOfComponents(int, int, int, int, int, int, int, int);

/*
* cpdf_getPageRotation(pdf, pagenumber) gets the viewing rotation for a
* given page.
*/
int cpdf_getPageRotation(int, int);

/*
* cpdf_hasBox(pdf, pagenumber, boxname) returns true, if that page has the
* given box. E.g "/CropBox".
*/
int cpdf_hasBox(int, int, const char[]);

/*
* These functions get a box given the document, page number, min x, max x,
* min y, max y in points. Only succeeds if such a box exists, as checked by
* cpdf_hasBox.
*/
void cpdf_getMediaBox(int, int, double *, double *, double *, double *);
void cpdf_getCropBox(int, int, double *, double *, double *, double *);
void cpdf_getTrimBox(int, int, double *, double *, double *, double *);
void cpdf_getArtBox(int, int, double *, double *, double *, double *);
void cpdf_getBleedBox(int, int, double *, double *, double *, double *);

/*
* These functions set a box given the document, page range, min x, max x,
* min y, max y in points.
*/
void cpdf_setMediabox(int, int, double, double, double, double);
void cpdf_setCropBox(int, int, double, double, double, double);
void cpdf_setTrimBox(int, int, double, double, double, double);
void cpdf_setArtBox(int, int, double, double, double, double);
void cpdf_setBleedBox(int, int, double, double, double, double);

/* cpdf_markTrapped(pdf) marks a document as trapped. */
void cpdf_markTrapped(int);

/* cpdf_markUntrapped(pdf) marks a document as untrapped. */
void cpdf_markUntrapped(int);

/* cpdf_markTrappedXMP(pdf) marks a document as trapped in XMP metadata. */
void cpdf_markTrappedXMP(int);

/* cpdf_markUntrappedXMP(pdf) marks a document as untrapped in XMP metadata. */
void cpdf_markUntrappedXMP(int);

/* Document Layouts. */
enum cpdf_layout {
  cpdf_singlePage,
  cpdf_oneColumn,
  cpdf_twoColumnLeft,
  cpdf_twoColumnRight,
  cpdf_twoPageLeft,
  cpdf_twoPageRight
};

/* cpdf_setPageLayout(pdf, layout) sets the page layout for a document. */
void cpdf_setPageLayout(int, enum cpdf_layout);

/* Document page modes. */
enum cpdf_pageMode {
  cpdf_useNone,
  cpdf_useOutlines,
  cpdf_useThumbs,
  cpdf_useOC,
  cpdf_useAttachments
};

/* cpdf_setPageMode(pdf, mode) sets the page mode for a document. */
void cpdf_setPageMode(int, enum cpdf_pageMode);

/* cpdf_hideToolbar(pdf, flag) sets the hide toolbar flag. */
void cpdf_hideToolbar(int, int);

/* cpdf_hideMenubar(pdf, flag) sets the hide menu bar flag. */
void cpdf_hideMenubar(int, int);

/* cpdf_hideWindowUi(pdf, flag) sets the hide window UI flag. */
void cpdf_hideWindowUi(int, int);

/* cpdf_fitWindow(pdf, flag) sets the fit window flag. */
void cpdf_fitWindow(int, int);

/* cpdf_centerWindow(pdf, flag) sets the center window flag. */
void cpdf_centerWindow(int, int);

/* cpdf_displayDocTitle(pdf, flag) sets the display doc title flag. */
void cpdf_displayDocTitle(int, int);

/* cpdf_openAtPage(pdf, fit, pagenumber) sets the PDF to open, possibly with
* zoom-to-fit, at the given page number. */
void cpdf_openAtPage(int, int, int);

/*
* cpdf_setMetadataFromFile(pdf, filename) set the XMP metadata of a
* document, given a file name.
*/
void cpdf_setMetadataFromFile(int, const char[]);

/*
* cpdf_setMetadataFromByteArray(pdf, data, length) set the XMP metadata from
* an array of bytes.
*/
void cpdf_setMetadataFromByteArray(int, void *, int);

/*
* cpdf_getMetadata(pdf, &length) returns the XMP metadata and fills in
* length.
*/
void *cpdf_getMetadata(int, int *);

/* cpdf_removeMetadata(pdf) removes the XMP metadata from a document. */
void cpdf_removeMetadata(int);

/*
* cpdf_createMetadata(pdf) builds fresh metadata as best it can from
* existing metadata in the document.
*/
void cpdf_createMetadata(int);

/*
* cpdf_setMetadataDate(pdf, date) sets the metadata date for a PDF. The date
* is given in PDF date format -- cpdf will convert it to XMP format. The
* date now means now.
*/
void cpdf_setMetadataDate(int, const char[]);

/* Styles of page label */
enum cpdf_pageLabelStyle {
  cpdf_decimalArabic,    /* 1, 2, 3... */
  cpdf_uppercaseRoman,   /* I, II, III... */
  cpdf_lowercaseRoman,   /* i, ii, iii... */
  cpdf_uppercaseLetters, /* A, B, C... */
  cpdf_lowercaseLetters  /* a, b, c... */
};

/*
* Add page labels.
*
* cpdf_addPageLabels(pdf, style, prefix, offset, range, progress)
*
* The prefix is prefix text for each label. The range is the page range the
* labels apply to. Offset can be used to shift the numbering up or down.
*/
void cpdf_addPageLabels(int, enum cpdf_pageLabelStyle, const char[], int, int,
                        int);

/* cpdf_removePageLabels(pdf) removes the page labels from the document. */
void cpdf_removePageLabels(int);

/*
* cpdf_getPageLabelStringForPage(pdf, page number) calculates the full label
* string for a given page, and returns it.
*/
char *cpdf_getPageLabelStringForPage(int, int);

/*
* Get page label data. Call cpdf_startGetPageLabels to find out how many
* there are, then use these serial numbers to get the style, prefix, offset
* and start value (note not a range). Call cpdf_endGetPageLabels to clean up.
*
* For example, a document might have five pages of introduction with roman
* numerals, followed by the rest of the pages in decimal arabic, numbered from
* one:
*
* labelstyle = LowercaseRoman
* labelprefix = ""
* startpage = 1
* startvalue = 1
*
* labelstyle = DecimalArabic
* labelprefix = ""
* startpage = 6
* startvalue = 1
*/
int cpdf_startGetPageLabels(int);
enum cpdf_pageLabelStyle cpdf_getPageLabelStyle(int);
char *cpdf_getPageLabelPrefix(int);
int cpdf_getPageLabelOffset(int);
int cpdf_getPageLabelRange(int);
void cpdf_endGetPageLabels();

Chapter 11
Document Information and Metadata

11.1 Reading Document Information

11.2 Setting Document Information

11.3 XMP Metadata

11.4 Upon Opening a Document

11.4.1 Page Layout

11.4.2 Page Mode

11.4.3 Display Options

11.5 Page Labels

C Interface

Chapter 11Document Information and Metadata

11.1 Reading Document Information

11.2 Setting Document Information

11.3 XMP Metadata

11.4 Upon Opening a Document

11.4.1 Page Layout

11.4.2 Page Mode

11.4.3 Display Options

11.5 Page Labels

C Interface

Chapter 11
Document Information and Metadata