SVG Surfaces: Cairo: A Vector Graphics Library

+ + +

SVG Surfaces

SVG Surfaces — Rendering SVG documents

Functions

++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

+cairo_surface_t * +	+cairo_svg_surface_create () +
+cairo_surface_t * +	+cairo_svg_surface_create_for_stream () +
+cairo_svg_unit_t +	+cairo_svg_surface_get_document_unit () +
+void +	+cairo_svg_surface_set_document_unit () +
+void +	+cairo_svg_surface_restrict_to_version () +
+void +	+cairo_svg_get_versions () +
const char * +	+cairo_svg_version_to_string () +

Types and Values

++++ + + + + + + + + + + + + + + +

#define	CAIRO_HAS_SVG_SURFACE
enum	cairo_svg_version_t
enum	cairo_svg_unit_t

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 "pt". This is for historical reasons.

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 1
+

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_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)

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

See also: +https://www.w3.org/TR/SVG/coords.htmlUnits +https://www.w3.org/TR/SVG/types.htmlDataTypeLength +https://www.w3.org/TR/css-values-3/lengths

Members

+++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

CAIRO_SVG_UNIT_USER
CAIRO_SVG_UNIT_EM
CAIRO_SVG_UNIT_EX
CAIRO_SVG_UNIT_PX
CAIRO_SVG_UNIT_IN
CAIRO_SVG_UNIT_CM
CAIRO_SVG_UNIT_MM
CAIRO_SVG_UNIT_PT
CAIRO_SVG_UNIT_PC
CAIRO_SVG_UNIT_PERCENT

Since: 1.16

SVG Surfaces

Functions

Types and Values

Description

Functions

cairo_svg_surface_create ()

Parameters

Returns

cairo_svg_surface_create_for_stream ()

Parameters

Returns

cairo_svg_surface_get_document_unit ()

Parameters

Returns

cairo_svg_surface_set_document_unit ()

Parameters

cairo_svg_surface_restrict_to_version ()

Parameters

cairo_svg_get_versions ()

Parameters

cairo_svg_version_to_string ()

Parameters

Returns

Types and Values

CAIRO_HAS_SVG_SURFACE

enum cairo_svg_version_t

Members

enum cairo_svg_unit_t

Members

See Also