RsvgHandle: Librsvg Reference Manual

## RsvgHandle RsvgHandle — Loads SVG data into memory. |

## Functions

GQuark | rsvg_error_quark ()
void | rsvg_cleanup ()
void | rsvg_set_default_dpi ()
void | rsvg_set_default_dpi_x_y ()
void | rsvg_handle_set_dpi ()
void | rsvg_handle_set_dpi_x_y ()
RsvgHandle * | rsvg_handle_new ()
RsvgHandle * | rsvg_handle_new_with_flags ()
gboolean | rsvg_handle_write ()
gboolean | rsvg_handle_close ()
const char * | rsvg_handle_get_base_uri ()
void | rsvg_handle_set_base_uri ()
void | rsvg_handle_get_dimensions ()
gboolean | rsvg_handle_get_dimensions_sub ()
gboolean | rsvg_handle_get_position_sub ()
gboolean | rsvg_handle_has_sub ()
const char * | rsvg_handle_get_title ()
const char * | rsvg_handle_get_desc ()
const char * | rsvg_handle_get_metadata ()
RsvgHandle * | rsvg_handle_new_from_data ()
RsvgHandle * | rsvg_handle_new_from_file ()
GType | rsvg_error_get_type ()
void | rsvg_init ()
void | rsvg_term ()
void | rsvg_handle_free ()
void | rsvg_handle_set_size_callback ()

## Types and Values

enum | RsvgError
#define | RSVG_ERROR
struct | RsvgHandle
typedef | RsvgHandlePrivate
struct | RsvgHandleClass
struct | RsvgDimensionData
struct | RsvgPositionData
#define | RSVG_TYPE_ERROR

## Description

This is the main entry point into the librsvg library. An RsvgHandle is an object that represents SVG data in memory. Your program creates an RsvgHandle from an SVG file, or from a memory buffer that contains SVG data, or in the most general form, from a GInputStream that will provide SVG data.

Librsvg supports reading SVG 1.1 data. It also supports SVGZ files, which is just an SVG stream compressed with the GZIP algorithm.

### The "base file" and resolving references to external files

When you load an SVG, librsvg needs to know the location of the "base file" for it. This is so that librsvg can determine the location of referenced entities. For example, say you have an SVG in `/foo/bar/foo.svg` and that it has an image element like this:

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    <image xlink:href="resources/foo.png" .../>

In this case, librsvg needs to know the location of the toplevel `/foo/bar/foo.svg` so that it can generate the appropriate reference to `/foo/bar/resources/foo.png`.

#### Security and locations of referenced files

When processing an SVG, librsvg will only load referenced files if they are in the same directory as the base file, or in a subdirectory of it. That is, if the base file is `/foo/bar/baz.svg`, then librsvg will only try to load referenced files (from SVG's "image" element, for example, or from content included through XML entities) if those files are in `/foo/bar/*` or in `/foo/bar/*/.../*`. This is so that malicious SVG files cannot include files that are in a directory above.

### Loading an SVG with GIO

If you have a GFile that stands for an SVG file, you can simply call `rsvg_handle_new_from_gfile_sync()` to load an RsvgHandle from it.

Alternatively, if you have a GInputStream, you can use `rsvg_handle_new_from_stream_sync()`.

Both of those methods allow specifying a GCancellable, so the loading process can be cancelled from another thread.

#### Loading an SVG from memory

If you already have SVG data in memory, you can create a memory input stream with `g_memory_input_stream_new_from_data()` and feed that to `rsvg_handle_new_from_stream_sync()`. This lets you specify the appropriate flags, for example RSVG_HANDLE_FLAG_UNLIMITED if your input data is very large.

Note that in this case, it is important that you specify the base_file for the in-memory SVG data. Librsvg uses the base_file to resolve links to external content, like raster images.

### Loading an SVG without GIO

You can load an RsvgHandle from a simple filename or URI with `rsvg_handle_new_from_file()`. Note that this is a blocking operation; there is no way to cancel it if loading a remote URI takes a long time.

Alternatively, you can create an empty RsvgHandle with `rsvg_handle_new()` or `rsvg_handle_new_with_flags()`. The first function is equivalent to using RSVG_HANDLE_FLAGS_NONE on the second one. These functions give you back an empty RsvgHandle, which is ready for you to feed it SVG data. You can do this with `rsvg_handle_write()` and `rsvg_handle_close()`.

### Resolution of the rendered image (dots per inch, or DPI)

SVG images can contain dimensions like "`5 cm`" or "`2 pt`" that must be converted from physical units into device units. To do this, librsvg needs to know the actual dots per inch (DPI) of your target device. You can call `rsvg_handle_set_dpi()` or `rsvg_handle_set_dpi_x_y()` on an RsvgHandle to set the DPI before rendering it.

### Rendering

The preferred way to render an already-loaded RsvgHandle is to use `rsvg_handle_render_cairo()`. Please see its documentation for details.

Alternatively, you can use `rsvg_handle_get_pixbuf()` to directly obtain a GdkPixbuf with the rendered image. This is simple, but it does not let you control the size at which the SVG will be rendered. It will just be rendered at the size which `rsvg_handle_get_dimensions()` would return, which depends on the dimensions that librsvg is able to compute from the SVG data.

## Functions

### rsvg_error_quark ()

    GQuark
    rsvg_error_quark (void);

The error domain for RSVG

#### Returns

The error domain

### rsvg_cleanup ()

    void
    rsvg_cleanup (void);

This function should not be called from normal programs. See `xmlCleanupParser()` for more information.

Since: 2.36

### rsvg_set_default_dpi ()

    void
    rsvg_set_default_dpi (double dpi);

`rsvg_set_default_dpi` has been deprecated since version 2.42.3 and should not be used in newly-written code.

This function used to set a global default DPI. However, it only worked if it was called before any RsvgHandle objects had been created; it would not work after that. To avoid global mutable state, please use `rsvg_handle_set_dpi()` instead.

Do not use this function. Create an RsvgHandle and call `rsvg_handle_set_dpi()` on it instead.

#### Parameters

dpi | Dots Per Inch (aka Pixels Per Inch) |

Since: 2.8

### rsvg_set_default_dpi_x_y ()

    void
    rsvg_set_default_dpi_x_y (double dpi_x,
                              double dpi_y);

`rsvg_set_default_dpi_x_y` has been deprecated since version 2.42.3 and should not be used in newly-written code.

This function used to set a global default DPI. However, it only worked if it was called before any RsvgHandle objects had been created; it would not work after that. To avoid global mutable state, please use `rsvg_handle_set_dpi()` instead.

Do not use this function. Create an RsvgHandle and call `rsvg_handle_set_dpi_x_y()` on it instead.

#### Parameters

dpi_x | Dots Per Inch (aka Pixels Per Inch) |
dpi_y | Dots Per Inch (aka Pixels Per Inch) |

Since: 2.8

### rsvg_handle_set_dpi ()

    void
    rsvg_handle_set_dpi (RsvgHandle *handle,
                         double dpi);

Sets the DPI for the outgoing pixbuf. Common values are 75, 90, and 300 DPI. Passing a number <= 0 to `dpi` will reset the DPI to whatever the default value happens to be.

#### Parameters

handle | An RsvgHandle |
dpi | Dots Per Inch (aka Pixels Per Inch) |

Since: 2.8

### rsvg_handle_set_dpi_x_y ()

    void
    rsvg_handle_set_dpi_x_y (RsvgHandle *handle,
                             double dpi_x,
                             double dpi_y);

Sets the DPI for the outgoing pixbuf. Common values are 75, 90, and 300 DPI. Passing a number <= 0 to dpi_x or `dpi_y` will reset the DPI to whatever the default value happens to be.

#### Parameters

handle | An RsvgHandle |
dpi_x | Dots Per Inch (aka Pixels Per Inch) |
dpi_y | Dots Per Inch (aka Pixels Per Inch) |

Since: 2.8

### rsvg_handle_new ()

    RsvgHandle *
    rsvg_handle_new (void);

Returns a new rsvg handle. Must be freed with `g_object_unref` . This handle can be used for dynamically loading an image. You need to feed it data using `rsvg_handle_write` , then call `rsvg_handle_close` when done. Afterwords, you can render it using Cairo or get a GdkPixbuf from it. When finished, free with `g_object_unref()`. No more than one image can be loaded with one handle.

#### Returns

A new RsvgHandle

### rsvg_handle_new_with_flags ()

    RsvgHandle *
    rsvg_handle_new_with_flags (RsvgHandleFlags flags);

Creates a new RsvgHandle with flags `flags` .

#### Parameters

flags | flags from RsvgHandleFlags |

#### Returns

a new RsvgHandle.

[transfer full]

Since: 2.36

### rsvg_handle_write ()

    gboolean
    rsvg_handle_write (RsvgHandle *handle,
                       const guchar *buf,
                       gsize count,
                       GError **error);

Loads the next `count` bytes of the image. This will return `TRUE` if the data was loaded successful, and `FALSE` if an error occurred. In the latter case, the loader will be closed, and will not accept further writes. If `FALSE` is returned, `error` will be set to an error from the RsvgError domain. Errors from GIOErrorEnum are also possible.

#### Parameters

handle | an RsvgHandle |
buf | pointer to svg data. | [array length=count][element-type guchar]
count | length of the `buf` buffer in bytes |
error | a location to store a GError, or `NULL`. | [allow-none]

#### Returns

`TRUE` on success, or `FALSE` on error

### rsvg_handle_close ()

    gboolean
    rsvg_handle_close (RsvgHandle *handle,
                       GError **error);

Closes `handle` , to indicate that loading the image is complete. This will return `TRUE` if the loader closed successfully. Note that `handle` isn't freed until `g_object_unref` is called.

#### Parameters

handle | a RsvgHandle |
error | a location to store a GError, or `NULL`. | [allow-none]

#### Returns

`TRUE` on success, or `FALSE` on error

### rsvg_handle_get_base_uri ()

    const char *
    rsvg_handle_get_base_uri (RsvgHandle *handle);

Gets the base uri for this RsvgHandle.

#### Parameters

handle | A RsvgHandle |

#### Returns

the base uri, possibly null

Since: 2.8

### rsvg_handle_set_base_uri ()

    void
    rsvg_handle_set_base_uri (RsvgHandle *handle,
                              const char *base_uri);

Set the base URI for this SVG. This can only be called before `rsvg_handle_write()` has been called.

#### Parameters

handle | A RsvgHandle |
base_uri | The base uri |

Since: 2.9

### rsvg_handle_get_dimensions ()

    void
    rsvg_handle_get_dimensions (RsvgHandle *handle,
                                RsvgDimensionData *dimension_data);

Get the SVG's size. Do not call from within the size_func callback, because an infinite loop will occur.

#### Parameters

handle | A RsvgHandle |
dimension_data | A place to store the SVG's size. | [out]

Since: 2.14

### rsvg_handle_get_dimensions_sub ()

    gboolean
    rsvg_handle_get_dimensions_sub (RsvgHandle *handle,
                                    RsvgDimensionData *dimension_data,
                                    const char *id);

Get the size of a subelement of the SVG file. Do not call from within the size_func callback, because an infinite loop will occur.

#### Parameters

handle | A RsvgHandle |
dimension_data | A place to store the SVG's size. | [out]
id | An element's id within the SVG, starting with "##", for example, "#layer1"; or `NULL` to use the whole SVG. | [nullable]

Since: 2.22

### rsvg_handle_get_position_sub ()

    gboolean
    rsvg_handle_get_position_sub (RsvgHandle *handle,
                                  RsvgPositionData *position_data,
                                  const char *id);

Get the position of a subelement of the SVG file. Do not call from within the size_func callback, because an infinite loop will occur.

#### Parameters

handle | A RsvgHandle |
position_data | A place to store the SVG fragment's position. | [out]
id | An element's id within the SVG, starting with "##", for example, "#layer1"; or `NULL` to use the whole SVG. | [nullable]

Since: 2.22

### rsvg_handle_has_sub ()

    gboolean
    rsvg_handle_has_sub (RsvgHandle *handle,
                         const char *id);

Checks whether the element `id` exists in the SVG document.

#### Parameters

handle | a RsvgHandle |
id | an element's id within the SVG, starting with "##", for example, "#layer1". |

#### Returns

`TRUE` if `id` exists in the SVG document

Since: 2.22

### rsvg_handle_get_title ()

    const char *
    rsvg_handle_get_title (RsvgHandle *handle);

`rsvg_handle_get_title` has been deprecated since version 2.36 and should not be used in newly-written code.

#### Parameters

handle | An RsvgHandle |

#### Returns

This function always returns NULL.

[nullable]

Since: 2.4

### rsvg_handle_get_desc ()

    const char *
    rsvg_handle_get_desc (RsvgHandle *handle);

`rsvg_handle_get_desc` has been deprecated since version 2.36 and should not be used in newly-written code.

#### Parameters

handle | An RsvgHandle |

#### Returns

This function always returns NULL.

[nullable]

Since: 2.4

### rsvg_handle_get_metadata ()

    const char *
    rsvg_handle_get_metadata (RsvgHandle *handle);

`rsvg_handle_get_metadata` has been deprecated since version 2.36 and should not be used in newly-written code.

#### Parameters

handle | An RsvgHandle |

#### Returns

This function always returns NULL.

[nullable]

Since: 2.9

### rsvg_handle_new_from_data ()

    RsvgHandle *
    rsvg_handle_new_from_data (const guint8 *data,
                               gsize data_len,
                               GError **error);

Loads the SVG specified by `data` .

#### Parameters

data | The SVG data. | [array length=data_len]
data_len | The length of `data` , in bytes |
error | return location for errors |

#### Returns

A RsvgHandle or `NULL` if an error occurs.

Since: 2.14

### rsvg_handle_new_from_file ()

    RsvgHandle *
    rsvg_handle_new_from_file (const gchar *file_name,
                               GError **error);

Loads the SVG specified by `file_name` .

#### Parameters

file_name | The file name to load. If built with gnome-vfs, can be a URI. |
error | return location for errors |

#### Returns

A RsvgHandle or `NULL` if an error occurs.

Since: 2.14

### rsvg_error_get_type ()

    GType
    rsvg_error_get_type (void);

### rsvg_init ()

    void
    rsvg_init (void);

`rsvg_init` has been deprecated since version 2.36 and should not be used in newly-written code.

There is no need to initialize librsvg.

This function does nothing.

Since: 2.9

### rsvg_term ()

    void
    rsvg_term (void);

`rsvg_term` has been deprecated since version 2.36 and should not be used in newly-written code.

There is no need to de-initialize librsvg.

This function does nothing.

Since: 2.9

### rsvg_handle_free ()

    void
    rsvg_handle_free (RsvgHandle *handle);

`rsvg_handle_free` is deprecated and should not be used in newly-written code.

Use `g_object_unref()` instead.

Frees `handle` .

#### Parameters

handle | An RsvgHandle |

### rsvg_handle_set_size_callback ()

    void
    rsvg_handle_set_size_callback (RsvgHandle *handle,
                                   RsvgSizeFunc size_func,
                                   gpointer user_data,
                                   GDestroyNotify user_data_destroy);

`rsvg_handle_set_size_callback` is deprecated and should not be used in newly-written code.

Set up a cairo matrix and use `rsvg_handle_render_cairo()` instead. You can call `rsvg_handle_get_dimensions()` to figure out the size of your SVG, and then scale it to the desired size via Cairo. For example, the following code renders an SVG at a specified size, scaled proportionally from whatever original size it may have had:

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    void
    render_scaled_proportionally (RsvgHandle *handle, cairo_t cr, int width, int height)
    {
        RsvgDimensionData dimensions;
        double x_factor, y_factor;
        double scale_factor;

        rsvg_handle_get_dimensions (handle, &dimensions);

        x_factor = (double) width / dimensions.width;
        y_factor = (double) height / dimensions.height;

        scale_factor = MIN (x_factor, y_factor);

        cairo_scale (cr, scale_factor, scale_factor);

        rsvg_handle_render_cairo (handle, cr);
    }

Sets the sizing function for the `handle` . This function is called right after the size of the image has been loaded. The size of the image is passed in to the function, which may then modify these values to set the real size of the generated pixbuf. If the image has no associated size, then the size arguments are set to -1.

#### Parameters

handle | An RsvgHandle |
size_func | A sizing function, or `NULL`. | [nullable]
user_data | User data to pass to `size_func` , or `NULL` |
user_data_destroy | Destroy function for `user_data` , or `NULL` |

## Types and Values

### enum RsvgError

An enumeration representing possible errors

#### Members

RSVG_ERROR_FAILED | the request failed |

### RSVG_ERROR

    #define RSVG_ERROR (rsvg_error_quark ())

### struct RsvgHandle

    struct RsvgHandle {
        GObject parent;
    };

Lets you load SVG data and render it.

#### Members

GObject `parent`; | parent instance |

### RsvgHandlePrivate

    typedef struct RsvgHandlePrivate RsvgHandlePrivate;

### struct RsvgHandleClass

    struct RsvgHandleClass {
        GObjectClass parent;
    };

Class structure for RsvgHandle.

#### Members

GObjectClass `parent`; | parent class |

### struct RsvgDimensionData

    struct RsvgDimensionData {
        int width;
        int height;
        gdouble em;
        gdouble ex;
    };

#### Members

int `width`; | SVG's width, in pixels |
int `height`; | SVG's height, in pixels |
gdouble `em`; | em |
gdouble `ex`; | ex |

### struct RsvgPositionData

    struct RsvgPositionData {
        int x;
        int y;
    };

Position of an SVG fragment.

#### Members

int `x`; | position on the x axis |
int `y`; | position on the y axis |

### RSVG_TYPE_ERROR

    #define RSVG_TYPE_ERROR (rsvg_error_get_type())