SVG Surfaces

SVG Surfaces — Rendering SVG documents

Functions

Types and Values

Description

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

Functions

cairo_svg_surface_create ()

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

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

The SVG surface backend recognizes the following MIME types for the data attached to a surface (see cairo_surface_set_mime_data()) when it is used as a source pattern for drawing on this surface: CAIRO_MIME_TYPE_JPEG, CAIRO_MIME_TYPE_PNG, CAIRO_MIME_TYPE_URI. If any of them is specified, the SVG backend emits a href with the content of MIME data instead of a surface snapshot (PNG, Base64-encoded) in the corresponding image tag.

The unofficial MIME type CAIRO_MIME_TYPE_URI is examined first. If present, the URI is emitted as is: assuring the correctness of URI is left to the client code.

If CAIRO_MIME_TYPE_URI is not present, but CAIRO_MIME_TYPE_JPEG or CAIRO_MIME_TYPE_PNG is specified, the corresponding data is Base64-encoded and emitted.

If CAIRO_MIME_TYPE_UNIQUE_ID is present, all surfaces with the same unique identifier will only be embedded once.

Parameters

filename

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

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

Creates a SVG 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_svg_surface_get_document_unit ()

cairo_svg_unit_t
cairo_svg_surface_get_document_unit (cairo_surface_t *surface);

Get the unit of the SVG surface.

If the surface passed as an argument is not a SVG surface, the function sets the error status to CAIRO_STATUS_SURFACE_TYPE_MISMATCH and returns CAIRO_SVG_UNIT_USER.

Parameters

surface

a SVG cairo_surface_t

 

Returns

the SVG unit of the SVG surface.

Since: 1.16


cairo_svg_surface_set_document_unit ()

void
cairo_svg_surface_set_document_unit (cairo_surface_t *surface,
                                     cairo_svg_unit_t unit);

Use the specified unit for the width and height of the generated SVG file. See cairo_svg_unit_t for a list of available unit values that can be used here.

This function can be called at any time before generating the SVG file.

However to minimize the risk of ambiguities it's recommended to call it before any drawing operations have been performed on the given surface, to make it clearer what the unit used in the drawing operations is.

The simplest way to do this is to call this function immediately after creating the SVG surface.

Note if this function is never called, the default unit for SVG documents generated by cairo will be user unit.

Parameters

surface

a SVG cairo_surface_t

 

unit

SVG unit

 

Since: 1.16


cairo_svg_surface_restrict_to_version ()

void
cairo_svg_surface_restrict_to_version (cairo_surface_t *surface,
                                       cairo_svg_version_t version);

Restricts the generated SVG file to version . See cairo_svg_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 SVG cairo_surface_t

 

version

SVG version

 

Since: 1.2


cairo_svg_get_versions ()

void
cairo_svg_get_versions (cairo_svg_version_t const **versions,
                        int *num_versions);

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

Parameters

versions

supported version list

 

num_versions

list length

 

Since: 1.2


cairo_svg_version_to_string ()

const char *
cairo_svg_version_to_string (cairo_svg_version_t version);

Get the string representation of the given version id. This function will return NULL if version isn't valid. See cairo_svg_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: 1.2

Types and Values

CAIRO_HAS_SVG_SURFACE

#define CAIRO_HAS_SVG_SURFACE

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

Since: 1.2


enum cairo_svg_version_t

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

Members

CAIRO_SVG_VERSION_1_1

The version 1.1 of the SVG specification. (Since 1.2)

 

CAIRO_SVG_VERSION_1_2

The version 1.2 of the SVG specification. (Since 1.2)

 

Since: 1.2


enum cairo_svg_unit_t

cairo_svg_unit_t is used to describe the units valid for coordinates and lengths in the SVG specification.

See also:

Members

CAIRO_SVG_UNIT_USER

User unit, a value in the current coordinate system. If used in the root element for the initial coordinate systems it corresponds to pixels. (Since 1.16)

 

CAIRO_SVG_UNIT_EM

The size of the element's font. (Since 1.16)

 

CAIRO_SVG_UNIT_EX

The x-height of the element’s font. (Since 1.16)

 

CAIRO_SVG_UNIT_PX

Pixels (1px = 1/96th of 1in). (Since 1.16)

 

CAIRO_SVG_UNIT_IN

Inches (1in = 2.54cm = 96px). (Since 1.16)

 

CAIRO_SVG_UNIT_CM

Centimeters (1cm = 96px/2.54). (Since 1.16)

 

CAIRO_SVG_UNIT_MM

Millimeters (1mm = 1/10th of 1cm). (Since 1.16)

 

CAIRO_SVG_UNIT_PT

Points (1pt = 1/72th of 1in). (Since 1.16)

 

CAIRO_SVG_UNIT_PC

Picas (1pc = 1/6th of 1in). (Since 1.16)

 

CAIRO_SVG_UNIT_PERCENT

Percent, a value that is some fraction of another reference value. (Since 1.16)

 

Since: 1.16

See Also

cairo_surface_t