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PDF Surfaces

PDF Surfaces — Rendering PDF documents

Description

The PDF surface is used to render cairo graphics to Adobe PDF files and is a multi-page vector surface backend.

The following mime types are supported: CAIRO_MIME_TYPE_JPEG, CAIRO_MIME_TYPE_JP2, CAIRO_MIME_TYPE_UNIQUE_ID, CAIRO_MIME_TYPE_JBIG2, CAIRO_MIME_TYPE_JBIG2_GLOBAL, CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID, CAIRO_MIME_TYPE_CCITT_FAX, CAIRO_MIME_TYPE_CCITT_FAX_PARAMS.

JBIG2 Images

JBIG2 data in PDF must be in the embedded format as described in ISO/IEC 11544. Image specific JBIG2 data must be in CAIRO_MIME_TYPE_JBIG2. Any global segments in the JBIG2 data (segments with page association field set to 0) must be in CAIRO_MIME_TYPE_JBIG2_GLOBAL. The global data may be shared by multiple images. All images sharing the same global data must set CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID to a unique identifier. At least one of the images must provide the global data using CAIRO_MIME_TYPE_JBIG2_GLOBAL. The global data will only be embedded once and shared by all JBIG2 images with the same CAIRO_MIME_TYPE_JBIG2_GLOBAL_ID.


CCITT Fax Images

The CAIRO_MIME_TYPE_CCITT_FAX mime data requires a number of decoding parameters These parameters are specified using CAIRO_MIME_TYPE_CCITT_FAX_PARAMS.

CAIRO_MIME_TYPE_CCITT_FAX_PARAMS mime data must contain a string of the form "param1=value1 param2=value2 ...".

Columns : [required] An integer specifying the width of the image in pixels.

Rows : [required] An integer specifying the height of the image in scan lines.

K : [optional] An integer identifying the encoding scheme used. < 0 is 2 dimensional Group 4, = 0 is Group3 1 dimensional, > 0 is mixed 1 and 2 dimensional encoding. Default is 0.

EndOfLine : [optional] If true end-of-line bit patterns are present. Default is false.

EncodedByteAlign : [optional] If true the end of line is padded with 0 bits so the next line begins on a byte boundary. Default is false.

EndOfBlock : [optional] If true the data contains an end-of-block pattern. Default is true.

BlackIs1 : [optional] If true 1 bits are black pixels. Default is false.

DamagedRowsBeforeError : [optional] An integer specifying the number of damages rows tolerated before an error occurs. Default is 0.

Boolean values may be "true" or "false", or 1 or 0.

These parameters are the same as the CCITTFaxDecode parameters in the PostScript Language Reference and Portable Document Format (PDF). Refer to these documents for further details.

An example CAIRO_MIME_TYPE_CCITT_FAX_PARAMS string is:

"Columns=10230 Rows=40000 K=1 EndOfLine=true EncodedByteAlign=1 BlackIs1=false"

Functions

cairo_pdf_surface_create ()

cairo_surface_t *
cairo_pdf_surface_create (const char *filename,
                          double width_in_points,
                          double height_in_points);

Creates a PDF surface of the specified size in points to be written to filename .

Parameters

filename

a filename for the PDF output (must be writable), NULL may be used to specify no output. This will generate a PDF surface that may be queried and used as a source, without generating a temporary file.

 

width_in_points

width of the surface, in points (1 point == 1/72.0 inch)

 

height_in_points

height of the surface, in points (1 point == 1/72.0 inch)

 

Returns

a pointer to the newly created surface. The caller owns the surface and should call cairo_surface_destroy() when done with it.

This function always returns a valid pointer, but it will return a pointer to a "nil" surface if an error such as out of memory occurs. You can use cairo_surface_status() to check for this.

Since: 1.2


cairo_pdf_surface_create_for_stream ()

cairo_surface_t *
cairo_pdf_surface_create_for_stream (cairo_write_func_t write_func,
                                     void *closure,
                                     double width_in_points,
                                     double height_in_points);

Creates a PDF surface of the specified size in points to be written incrementally to the stream represented by write_func and closure .

Parameters

write_func

a cairo_write_func_t to accept the output data, may be NULL to indicate a no-op write_func . With a no-op write_func , the surface may be queried or used as a source without generating any temporary files.

 

closure

the closure argument for write_func

 

width_in_points

width of the surface, in points (1 point == 1/72.0 inch)

 

height_in_points

height of the surface, in points (1 point == 1/72.0 inch)

 

Returns

a pointer to the newly created surface. The caller owns the surface and should call cairo_surface_destroy() when done with it.

This function always returns a valid pointer, but it will return a pointer to a "nil" surface if an error such as out of memory occurs. You can use cairo_surface_status() to check for this.

Since: 1.2


cairo_pdf_surface_restrict_to_version ()

void
cairo_pdf_surface_restrict_to_version (cairo_surface_t *surface,
                                       cairo_pdf_version_t version);

Restricts the generated PDF file to version . See cairo_pdf_get_versions() for a list of available version values that can be used here.

This function should only be called before any drawing operations have been performed on the given surface. The simplest way to do this is to call this function immediately after creating the surface.

Parameters

surface

a PDF cairo_surface_t

 

version

PDF version

 

Since: 1.10


cairo_pdf_get_versions ()

void
cairo_pdf_get_versions (cairo_pdf_version_t const **versions,
                        int *num_versions);

Used to retrieve the list of supported versions. See cairo_pdf_surface_restrict_to_version().

Parameters

versions

supported version list

 

num_versions

list length

 

Since: 1.10


cairo_pdf_version_to_string ()

const char *
cairo_pdf_version_to_string (cairo_pdf_version_t version);

Get the string representation of the given version id. This function will return NULL if version isn't valid. See cairo_pdf_get_versions() for a way to get the list of valid version ids.

Parameters

version

a version id

 

Returns

the string associated to given version.

Since: 1.10


cairo_pdf_surface_set_size ()

void
cairo_pdf_surface_set_size (cairo_surface_t *surface,
                            double width_in_points,
                            double height_in_points);

Changes the size of a PDF surface for the current (and subsequent) pages.

This function should only be called before any drawing operations have been performed on the current page. The simplest way to do this is to call this function immediately after creating the surface or immediately after completing a page with either cairo_show_page() or cairo_copy_page().

Parameters

surface

a PDF cairo_surface_t

 

width_in_points

new surface width, in points (1 point == 1/72.0 inch)

 

height_in_points

new surface height, in points (1 point == 1/72.0 inch)

 

Since: 1.2


cairo_pdf_surface_add_outline ()

int
cairo_pdf_surface_add_outline (cairo_surface_t *surface,
                               int parent_id,
                               const char *utf8,
                               const char *link_attribs,
                               cairo_pdf_outline_flags_t flags);

Add an item to the document outline hierarchy with the name utf8 that links to the location specified by link_attribs . Link attributes have the same keys and values as the Link Tag, excluding the "rect" attribute. The item will be a child of the item with id parent_id . Use CAIRO_PDF_OUTLINE_ROOT as the parent id of top level items.

Parameters

surface

a PDF cairo_surface_t

 

parent_id

the id of the parent item or CAIRO_PDF_OUTLINE_ROOT if this is a top level item.

 

utf8

the name of the outline

 

link_attribs

the link attributes specifying where this outline links to

 

flags

outline item flags

 

Returns

the id for the added item.

Since: 1.16


cairo_pdf_surface_set_metadata ()

void
cairo_pdf_surface_set_metadata (cairo_surface_t *surface,
                                cairo_pdf_metadata_t metadata,
                                const char *utf8);

Set document metadata. The CAIRO_PDF_METADATA_CREATE_DATE and CAIRO_PDF_METADATA_MOD_DATE values must be in ISO-8601 format: YYYY-MM-DDThh:mm:ss. An optional timezone of the form "[+/-]hh:mm" or "Z" for UTC time can be appended. All other metadata values can be any UTF-8 string.

For example:

1
2
cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_TITLE, "My Document");
cairo_pdf_surface_set_metadata (surface, CAIRO_PDF_METADATA_CREATE_DATE, "2015-12-31T23:59+02:00");

Parameters

surface

a PDF cairo_surface_t

 

metadata

The metadata item to set.

 

utf8

metadata value

 

Since: 1.16


cairo_pdf_surface_set_page_label ()

void
cairo_pdf_surface_set_page_label (cairo_surface_t *surface,
                                  const char *utf8);

Set page label for the current page.

Parameters

surface

a PDF cairo_surface_t

 

utf8

The page label.

 

Since: 1.16


cairo_pdf_surface_set_thumbnail_size ()

void
cairo_pdf_surface_set_thumbnail_size (cairo_surface_t *surface,
                                      int width,
                                      int height);

Set the thumbnail image size for the current and all subsequent pages. Setting a width or height of 0 disables thumbnails for the current and subsequent pages.

Parameters

surface

a PDF cairo_surface_t

 

width

Thumbnail width.

 

height

Thumbnail height

 

Since: 1.16

Types and Values

CAIRO_HAS_PDF_SURFACE

#define CAIRO_HAS_PDF_SURFACE 1

Defined if the PDF surface backend is available. This macro can be used to conditionally compile backend-specific code.

Since: 1.2


CAIRO_PDF_OUTLINE_ROOT

#define CAIRO_PDF_OUTLINE_ROOT 0

The root outline item in cairo_pdf_surface_add_outline().

Since: 1.16


enum cairo_pdf_outline_flags_t

cairo_pdf_outline_flags_t is used by the cairo_pdf_surface_add_outline() function specify the attributes of an outline item. These flags may be bitwise-or'd to produce any combination of flags.

Members

CAIRO_PDF_OUTLINE_FLAG_OPEN

The outline item defaults to open in the PDF viewer (Since 1.16)

 

CAIRO_PDF_OUTLINE_FLAG_BOLD

The outline item is displayed by the viewer in bold text (Since 1.16)

 

CAIRO_PDF_OUTLINE_FLAG_ITALIC

The outline item is displayed by the viewer in italic text (Since 1.16)

 

Since: 1.16


enum cairo_pdf_metadata_t

cairo_pdf_metadata_t is used by the cairo_pdf_surface_set_metadata() function specify the metadata to set.

Members

CAIRO_PDF_METADATA_TITLE

The document title (Since 1.16)

 

CAIRO_PDF_METADATA_AUTHOR

The document author (Since 1.16)

 

CAIRO_PDF_METADATA_SUBJECT

The document subject (Since 1.16)

 

CAIRO_PDF_METADATA_KEYWORDS

The document keywords (Since 1.16)

 

CAIRO_PDF_METADATA_CREATOR

The document creator (Since 1.16)

 

CAIRO_PDF_METADATA_CREATE_DATE

The document creation date (Since 1.16)

 

CAIRO_PDF_METADATA_MOD_DATE

The document modification date (Since 1.16)

 

Since: 1.16


enum cairo_pdf_version_t

cairo_pdf_version_t is used to describe the version number of the PDF specification that a generated PDF file will conform to.

Members

CAIRO_PDF_VERSION_1_4

The version 1.4 of the PDF specification. (Since 1.10)

 

CAIRO_PDF_VERSION_1_5

The version 1.5 of the PDF specification. (Since 1.10)

 

Since: 1.10

See Also

cairo_surface_t

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