PostScript Surfaces

PostScript Surfaces — Rendering PostScript documents

Functions

Types and Values

Object Hierarchy


Description

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

Functions

cairo_ps_surface_create ()

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

Creates a PostScript surface of the specified size in points to be written to filename . See cairo_ps_surface_create_for_stream() for a more flexible mechanism for handling the PostScript output than simply writing it to a named file.

Note that the size of individual pages of the PostScript output can vary. See cairo_ps_surface_set_size().

Parameters

filename

a filename for the PS output (must be writable), NULL may be used to specify no output. This will generate a PS 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_ps_surface_create_for_stream ()

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

Creates a PostScript surface of the specified size in points to be written incrementally to the stream represented by write_func and closure . See cairo_ps_surface_create() for a more convenient way to simply direct the PostScript output to a named file.

Note that the size of individual pages of the PostScript output can vary. See cairo_ps_surface_set_size().

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_ps_surface_restrict_to_level ()

void
cairo_ps_surface_restrict_to_level (cairo_surface_t *surface,
                                    cairo_ps_level_t level);

Restricts the generated PostSript file to level . See cairo_ps_get_levels() for a list of available level 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 PostScript cairo_surface_t

 

level

PostScript level

 

Since 1.6


cairo_ps_get_levels ()

void
cairo_ps_get_levels (cairo_ps_level_t const **levels,
                     int *num_levels);

Used to retrieve the list of supported levels. See cairo_ps_surface_restrict_to_level().

Parameters

levels

supported level list

 

num_levels

list length

 

Since 1.6


cairo_ps_level_to_string ()

const char *
cairo_ps_level_to_string (cairo_ps_level_t level);

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

Parameters

level

a level id

 

Returns

the string associated to given level.

Since 1.6


cairo_ps_surface_set_eps ()

void
cairo_ps_surface_set_eps (cairo_surface_t *surface,
                          cairo_bool_t eps);

If eps is TRUE, the PostScript surface will output Encapsulated PostScript.

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. An Encapsulated PostScript file should never contain more than one page.

Parameters

surface

a PostScript cairo_surface_t

 

eps

TRUE to output EPS format PostScript

 

Since 1.6


cairo_ps_surface_get_eps ()

cairo_bool_t
cairo_ps_surface_get_eps (cairo_surface_t *surface);

Check whether the PostScript surface will output Encapsulated PostScript.

Parameters

surface

a PostScript cairo_surface_t

 

Returns

TRUE if the surface will output Encapsulated PostScript.

Since 1.6


cairo_ps_surface_set_size ()

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

Changes the size of a PostScript 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 PostScript 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_ps_surface_dsc_begin_setup ()

void
cairo_ps_surface_dsc_begin_setup (cairo_surface_t *surface);

This function indicates that subsequent calls to cairo_ps_surface_dsc_comment() should direct comments to the Setup section of the PostScript output.

This function should be called at most once per surface, and must be called before any call to cairo_ps_surface_dsc_begin_page_setup() and before any drawing is performed to the surface.

See cairo_ps_surface_dsc_comment() for more details.

Parameters

surface

a PostScript cairo_surface_t

 

Since 1.2


cairo_ps_surface_dsc_begin_page_setup ()

void
cairo_ps_surface_dsc_begin_page_setup (cairo_surface_t *surface);

This function indicates that subsequent calls to cairo_ps_surface_dsc_comment() should direct comments to the PageSetup section of the PostScript output.

This function call is only needed for the first page of a surface. It should be called after any call to cairo_ps_surface_dsc_begin_setup() and before any drawing is performed to the surface.

See cairo_ps_surface_dsc_comment() for more details.

Parameters

surface

a PostScript cairo_surface_t

 

Since 1.2


cairo_ps_surface_dsc_comment ()

void
cairo_ps_surface_dsc_comment (cairo_surface_t *surface,
                              const char *comment);

Emit a comment into the PostScript output for the given surface.

The comment is expected to conform to the PostScript Language Document Structuring Conventions (DSC). Please see that manual for details on the available comments and their meanings. In particular, the %%IncludeFeature comment allows a device-independent means of controlling printer device features. So the PostScript Printer Description Files Specification will also be a useful reference.

The comment string must begin with a percent character (%) and the total length of the string (including any initial percent characters) must not exceed 255 characters. Violating either of these conditions will place surface into an error state. But beyond these two conditions, this function will not enforce conformance of the comment with any particular specification.

The comment string should not have a trailing newline.

The DSC specifies different sections in which particular comments can appear. This function provides for comments to be emitted within three sections: the header, the Setup section, and the PageSetup section. Comments appearing in the first two sections apply to the entire document while comments in the BeginPageSetup section apply only to a single page.

For comments to appear in the header section, this function should be called after the surface is created, but before a call to cairo_ps_surface_dsc_begin_setup().

For comments to appear in the Setup section, this function should be called after a call to cairo_ps_surface_dsc_begin_setup() but before a call to cairo_ps_surface_dsc_begin_page_setup().

For comments to appear in the PageSetup section, this function should be called after a call to cairo_ps_surface_dsc_begin_page_setup().

Note that it is only necessary to call cairo_ps_surface_dsc_begin_page_setup() for the first page of any surface. After a call to cairo_show_page() or cairo_copy_page() comments are unambiguously directed to the PageSetup section of the current page. But it doesn't hurt to call this function at the beginning of every page as that consistency may make the calling code simpler.

As a final note, cairo automatically generates several comments on its own. As such, applications must not manually generate any of the following comments:

Header section: %!PS-Adobe-3.0, %%Creator, %%CreationDate, %%Pages, %%BoundingBox, %%DocumentData, %%LanguageLevel, %%EndComments.

Setup section: %%BeginSetup, %%EndSetup

PageSetup section: %%BeginPageSetup, %%PageBoundingBox, %%EndPageSetup.

Other sections: %%BeginProlog, %%EndProlog, %%Page, %%Trailer, %%EOF

Here is an example sequence showing how this function might be used:

cairo_surface_t *surface = cairo_ps_surface_create (filename, width, height);
...
cairo_ps_surface_dsc_comment (surface, "%%Title: My excellent document");
cairo_ps_surface_dsc_comment (surface, "%%Copyright: Copyright (C) 2006 Cairo Lover")
...
cairo_ps_surface_dsc_begin_setup (surface);
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *MediaColor White");
...
cairo_ps_surface_dsc_begin_page_setup (surface);
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *PageSize A3");
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *InputSlot LargeCapacity");
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *MediaType Glossy");
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *MediaColor Blue");
... draw to first page here ..
cairo_show_page (cr);
...
cairo_ps_surface_dsc_comment (surface, "%%IncludeFeature: *PageSize A5");
...

Parameters

surface

a PostScript cairo_surface_t

 

comment

a comment string to be emitted into the PostScript output

 

Since 1.2

Types and Values

CAIRO_HAS_PS_SURFACE

#define CAIRO_HAS_PS_SURFACE 1

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

Since 1.2


enum cairo_ps_level_t

cairo_ps_level_t is used to describe the language level of the PostScript Language Reference that a generated PostScript file will conform to.

Members

CAIRO_PS_LEVEL_2

The language level 2 of the PostScript specification. (Since 1.6)

 

CAIRO_PS_LEVEL_3

The language level 3 of the PostScript specification. (Since 1.6)

 

Since 1.6

See Also

cairo_surface_t