gi-rsvg-2.0.3: librsvg bindings
Copyright Will Thompson and Iñaki García Etxebarria LGPL-2.1 Iñaki García Etxebarria Safe-Inferred Haskell2010

GI.Rsvg.Objects.Handle

Description

Handle loads an SVG document into memory.

This is the main entry point into the librsvg library. An Handle is an object that represents SVG data in memory. Your program creates an Handle 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 can load SVG images and render them to Cairo surfaces, using a mixture of SVG's [static mode] and [secure static mode]. Librsvg does not do animation nor scripting, and can load references to external data only in some situations; see below.

Librsvg supports reading SVG 1.1 data, and is gradually adding support for features in SVG 2. Librsvg also supports SVGZ files, which are just an SVG stream compressed with the GZIP algorithm.

static mode
https://www.w3.org/TR/SVG2/conform.htmlstatic-mode
secure static mode
https://www.w3.org/TR/SVG2/conform.htmlsecure-static-mode

# 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:

<image 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/<anything> or in /foo/bar/<anything>\/.../<anything>. This is so that malicious SVG files cannot include files that are in a directory above.

The full set of rules for deciding which URLs may be loaded is as follows; they are applied in order. A referenced URL will not be loaded as soon as one of these rules fails:

1. All data: URLs may be loaded. These are sometimes used to include raster image data, encoded as base-64, directly in an SVG file.
2. All other URL schemes in references require a base URL. For example, this means that if you load an SVG with handleNewFromData without calling handleSetBaseUri, then any referenced files will not be allowed (e.g. raster images to be loaded from other files will not work).
3. If referenced URLs are absolute, rather than relative, then they must have the same scheme as the base URL. For example, if the base URL has a file scheme, then all URL references inside the SVG must also have the file scheme, or be relative references which will be resolved against the base URL.
4. If referenced URLs have a resource scheme, that is, if they are included into your binary program with GLib's resource mechanism, they are allowed to be loaded (provided that the base URL is also a resource, per the previous rule).
5. Otherwise, non-file schemes are not allowed. For example, librsvg will not load http resources, to keep malicious SVG data from "phoning home".
6. A relative URL must resolve to the same directory as the base URL, or to one of its subdirectories. Librsvg will canonicalize filenames, by removing ".." path components and resolving symbolic links, to decide whether files meet these conditions.

This is the easiest and most resource-efficient way of loading SVG data into an Handle.

If you have a GFile that stands for an SVG file, you can simply call handleNewFromGfileSync to load an Handle from it.

Alternatively, if you have a GInputStream, you can use handleNewFromStreamSync.

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

If you already have SVG data in a byte buffer in memory, you can create a memory input stream with memoryInputStreamNewFromData and feed that to handleNewFromStreamSync.

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.

You can load an Handle from a simple filename or URI with handleNewFromFile. Note that this is a blocking operation; there is no way to cancel it if loading a remote URI takes a long time. Also, note that this method does not let you specify [flagsrsvg.HandleFlags].

Otherwise, loading an SVG without GIO is not recommended, since librsvg will need to buffer your entire data internally before actually being able to parse it. The deprecated way of doing this is by creating a handle with handleNew or handleNewWithFlags, and then using handleWrite and handleClose to feed the handle with SVG data. Still, please try to use the GIO stream functions instead.

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

SVG images can contain dimensions like "5cm" or "2pt" 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 handleSetDpi or handleSetDpiXY on an Handle to set the DPI before rendering it.

# Rendering

The preferred way to render a whole SVG document is to use handleRenderDocument. Please see its documentation for details.

# API ordering

Due to the way the librsvg API evolved over time, an Handle object is available for use as soon as it is constructed. However, not all of its methods can be called at any time. For example, an Handle just constructed with handleNew is not loaded yet, and it does not make sense to call handleRenderDocument on it just at that point.

The documentation for the available methods in Handle may mention that a particular method is only callable on a "fully loaded handle". This means either:

• The handle was loaded with handleWrite and handleClose, and those functions returned no errors.
• The handle was loaded with handleReadStreamSync and that function returned no errors.

Before librsvg 2.46, the library did not fully verify that a handle was in a fully loaded state for the methods that require it. To preserve compatibility with old code which inadvertently called the API without checking for errors, or which called some methods outside of the expected order, librsvg will just emit a g_critical() message in those cases.

New methods introduced in librsvg 2.46 and later will check for the correct ordering, and panic if they are called out of order. This will abort the program as if it had a failed assertion.

Synopsis

# Exported types

newtype Handle Source #

Memory-managed wrapper type.

Constructors

 Handle (ManagedPtr Handle)

#### Instances

Instances details
 Source # Instance detailsDefined in GI.Rsvg.Objects.Handle Methods(==) :: Handle -> Handle -> Bool #(/=) :: Handle -> Handle -> Bool # GObject Handle Source # Instance detailsDefined in GI.Rsvg.Objects.Handle ManagedPtrNewtype Handle Source # Instance detailsDefined in GI.Rsvg.Objects.Handle MethodstoManagedPtr :: Handle -> ManagedPtr Handle TypedObject Handle Source # Instance detailsDefined in GI.Rsvg.Objects.Handle MethodsglibType :: IO GType HasParentTypes Handle Source # Instance detailsDefined in GI.Rsvg.Objects.Handle IsGValue (Maybe Handle) Source # Convert Handle to and from GValue. See toGValue and fromGValue. Instance detailsDefined in GI.Rsvg.Objects.Handle MethodsgvalueGType_ :: IO GTypegvalueSet_ :: Ptr GValue -> Maybe Handle -> IO ()gvalueGet_ :: Ptr GValue -> IO (Maybe Handle) type ParentTypes Handle Source # Instance detailsDefined in GI.Rsvg.Objects.Handle type ParentTypes Handle = '[Object]

class (GObject o, IsDescendantOf Handle o) => IsHandle o Source #

Type class for types which can be safely cast to Handle, for instance with toHandle.

#### Instances

Instances details
 (GObject o, IsDescendantOf Handle o) => IsHandle o Source # Instance detailsDefined in GI.Rsvg.Objects.Handle

toHandle :: (MonadIO m, IsHandle o) => o -> m Handle Source #

Cast to Handle, for types for which this is known to be safe. For general casts, use castTo.

# Methods

Expand

## close

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: a Handle -> m () (Can throw GError)

Deprecated: (Since version 2.46.)Use handleReadStreamSync or the constructorfunctions handleNewFromGfileSync orhandleNewFromStreamSync. See the deprecation notes forhandleWrite for more information.

This is used after calling handleWrite to indicate that there is no more data to consume, and to start the actual parsing of the SVG document. The only reason to call this function is if you use use handleWrite to feed data into the handle; if you use the other methods like handleNewFromFile or handleReadStreamSync, then you do not need to call this function.

This will return TRUE if the loader closed successfully and the SVG data was parsed correctly. Note that handle isn't freed until objectUnref is called.

## free

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m ()

Deprecated: Use objectUnref instead.

Frees handle.

## getBaseUri

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> m Text Returns: the base uri, possibly null

Gets the base uri for this Handle.

Since: 2.8

## getDesc

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Maybe Text) Returns: This function always returns NULL.

Deprecated: (Since version 2.36.)Librsvg does not read the metadata/desc/title elements;this function always returns NULL.

No description available in the introspection data.

Since: 2.4

## getDimensions

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> m DimensionData

Deprecated: (Since version 2.52.)Use handleGetIntrinsicSizeInPixels instead. Thisfunction is deprecated because it is not able to return exact fractional dimensions,only integer pixels.

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

This function depends on the Handle's DPI to compute dimensions in pixels, so you should call handleSetDpi beforehand.

Since: 2.14

## getDimensionsSub

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to use the whole SVG. -> m (Bool, DimensionData) Returns: TRUE if the dimensions could be obtained, FALSE if there was an error.

Deprecated: (Since version 2.46.)Use handleGetGeometryForLayer instead.

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.

This function depends on the Handle's DPI to compute dimensions in pixels, so you should call handleSetDpi beforehand.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

Since: 2.22

## getGeometryForElement

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to compute the geometry for the whole SVG. -> m (Rectangle, Rectangle) (Can throw GError)

Computes the ink rectangle and logical rectangle of a single SVG element.

While rsvg_handle_get_geometry_for_layer computes the geometry of an SVG element subtree with its transformation matrix, this other function will compute the element's geometry as if it were being rendered under an identity transformation by itself. That is, the resulting geometry is as if the element got extracted by itself from the SVG.

This function is the counterpart to rsvg_handle_render_element.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

The "ink rectangle" is the bounding box that would be painted for fully- stroked and filled elements.

The "logical rectangle" just takes into account the unstroked paths and text outlines.

Note that these bounds are not minimum bounds; for example, clipping paths are not taken into account.

You can pass NULL for the id if you want to measure all the elements in the SVG, i.e. to measure everything from the root element.

This operation is not constant-time, as it involves going through all the child elements.

Since: 2.46

## getGeometryForLayer

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to compute the geometry for the whole SVG. -> Rectangle viewport: Viewport size at which the whole SVG would be fitted. -> m (Rectangle, Rectangle) (Can throw GError)

Computes the ink rectangle and logical rectangle of an SVG element, or the whole SVG, as if the whole SVG were rendered to a specific viewport.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

The "ink rectangle" is the bounding box that would be painted for fully-stroked and filled elements.

The "logical rectangle" just takes into account the unstroked paths and text outlines.

Note that these bounds are not minimum bounds; for example, clipping paths are not taken into account.

You can pass NULL for the id if you want to measure all the elements in the SVG, i.e. to measure everything from the root element.

This operation is not constant-time, as it involves going through all the child elements.

Since: 2.46

## getIntrinsicDimensions

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Bool, Length, Bool, Length, Bool, Rectangle)

In simple terms, queries the width, height, and viewBox attributes in an SVG document.

If you are calling this function to compute a scaling factor to render the SVG, consider simply using handleRenderDocument instead; it will do the scaling computations automatically.

Before librsvg 2.54.0, the out_has_width and out_has_height arguments would be set to true or false depending on whether the SVG document actually had width and height attributes, respectively.

However, since librsvg 2.54.0, width and height are now <https://www.w3.org/TR/SVG2/geometry.html geometry properties> per the SVG2 specification; they are not plain attributes. SVG2 made it so that the initial value of those properties is auto, which is equivalent to specifing a value of 100%. In this sense, even SVG documents which lack width or height attributes semantically have to make them default to 100%. This is why since librsvg 2.54.0, out_has_width and out_has_heigth are always returned as TRUE, since with SVG2 all documents *have* a default width and height of 100%.

As an example, the following SVG element has a width of 100 pixels and a height of 400 pixels, but no viewBox. This function will return those sizes in out_width and out_height, and set out_has_viewbox to FALSE.

<svg xmlns="http://www.w3.org/2000/svg" width="100" height="400">

Conversely, the following element has a viewBox, but no width or height. This function will set out_has_viewbox to TRUE, and it will also set out_has_width and out_has_height to TRUE but return both length values as 100%.

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 400">

Note that the RsvgLength return values have RsvgUnits in them; you should not assume that they are always in pixels. For example, the following SVG element will return width and height values whose units fields are RSVG_UNIT_MM.

<svg xmlns="http://www.w3.org/2000/svg" width="210mm" height="297mm">

API ordering: This function must be called on a fully-loaded handle. See the section "API ordering" for details.

Panics: this function will panic if the handle is not fully-loaded.

Since: 2.46

## getIntrinsicSizeInPixels

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Bool, Double, Double) Returns: TRUE if the dimensions could be converted directly to pixels; in this case outWidth and outHeight will be set accordingly. Note that the dimensions are floating-point numbers, so your application can know the exact size of an SVG document. To get integer dimensions, you should use ceil() to round up to the nearest integer (just using round(), may may chop off pixels with fractional coverage). If the dimensions cannot be converted to pixels, returns FALSE and puts 0.0 in both outWidth and outHeight.

Converts an SVG document's intrinsic dimensions to pixels, and returns the result.

This function is able to extract the size in pixels from an SVG document if the document has both width and height attributes with physical units (px, in, cm, mm, pt, pc) or font-based units (em, ex). For physical units, the dimensions are normalized to pixels using the dots-per-inch (DPI) value set previously with handleSetDpi. For font-based units, this function uses the computed value of the font-size property for the toplevel <svg> element. In those cases, this function returns TRUE.

This function is not able to extract the size in pixels directly from the intrinsic dimensions of the SVG document if the width or height are in percentage units (or if they do not exist, in which case the SVG spec mandates that they default to 100%), as these require a <firstterm>viewport</firstterm> to be resolved to a final size. In this case, the function returns FALSE.

For example, the following document fragment has intrinsic dimensions that will resolve to 20x30 pixels.

<svg xmlns="http://www.w3.org/2000/svg" width="20" height="30"/>

Similarly, if the DPI is set to 96, this document will resolve to 192×288 pixels (i.e. 96×2 × 96×3).

<svg xmlns="http://www.w3.org/2000/svg" width="2in" height="3in"/>

The dimensions of the following documents cannot be resolved to pixels directly, and this function would return FALSE for them:

<!-- Needs a viewport against which to compute the percentages. -->
<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%"/>

<!-- Does not have intrinsic width/height, just a 1:2 aspect ratio which
needs to be fitted within a viewport. -->
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 200"/>

Instead of querying an SVG document's size, applications are encouraged to render SVG documents to a size chosen by the application, by passing a suitably-sized viewport to handleRenderDocument.

Since: 2.52

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Maybe Text) Returns: This function always returns NULL.

Deprecated: (Since version 2.36.)Librsvg does not read the metadata/desc/title elements;this function always returns NULL.

No description available in the introspection data.

Since: 2.9

## getPixbuf

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Maybe Pixbuf) Returns: A pixbuf, or Nothing on error. during rendering.

Returns the pixbuf loaded by handle. The pixbuf returned will be reffed, so the caller of this function must assume that ref.

API ordering: This function must be called on a fully-loaded handle. See the section "API ordering" for details.

This function depends on the Handle's dots-per-inch value (DPI) to compute the "natural size" of the document in pixels, so you should call handleSetDpi beforehand.

## getPixbufSub

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to use the whole SVG. -> m (Maybe Pixbuf) Returns: a pixbuf, or NULL if an error occurs during rendering.

Creates a GdkPixbuf the same size as the entire SVG loaded into handle, but only renders the sub-element that has the specified id (and all its sub-sub-elements recursively). If id is NULL, this function renders the whole SVG.

This function depends on the Handle's dots-per-inch value (DPI) to compute the "natural size" of the document in pixels, so you should call handleSetDpi beforehand.

If you need to render an image which is only big enough to fit a particular sub-element of the SVG, consider using handleRenderElement.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

API ordering: This function must be called on a fully-loaded handle. See the section "API ordering" for details.

Since: 2.14

## getPositionSub

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass Nothing to use the whole SVG. -> m (Bool, PositionData) Returns: TRUE if the position could be obtained, FALSE if there was an error.

Deprecated: (Since version 2.46.)Use handleGetGeometryForLayer instead. This function isdeprecated since it is not able to return exact floating-point positions, only integerpixels.

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.

This function depends on the Handle's DPI to compute dimensions in pixels, so you should call handleSetDpi beforehand.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

Since: 2.22

## getTitle

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> m (Maybe Text) Returns: This function always returns NULL.

Deprecated: (Since version 2.36.)Librsvg does not read the metadata/desc/title elements;this function always returns NULL.

No description available in the introspection data.

Since: 2.4

## hasSub

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: a Handle -> Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. -> m Bool Returns: TRUE if id exists in the SVG document, FALSE otherwise.

Checks whether the element id exists in the SVG document.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

Since: 2.22

## internalSetTesting

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: a Handle -> Bool testing: Whether to enable testing mode -> m ()

Do not call this function. This is intended for librsvg's internal test suite only.

## new

Arguments

 :: (HasCallStack, MonadIO m) => m Handle Returns: A new Handle with no flags set.

Returns a new rsvg handle. Must be freed with objectUnref. This handle can be used to load an image.

The preferred way of loading SVG data into the returned Handle is with handleReadStreamSync.

The deprecated way of loading SVG data is with handleWrite and handleClose; note that these require buffering the entire file internally, and for this reason it is better to use the stream functions: handleNewFromStreamSync, handleReadStreamSync, or handleNewFromGfileSync.

After loading the Handle with data, you can render it using Cairo or get a GdkPixbuf from it. When finished, free the handle with objectUnref. No more than one image can be loaded with one handle.

Note that this function creates an Handle with no flags set. If you require any of [flagsrsvg.HandleFlags] to be set, use any of handleNewWithFlags, handleNewFromStreamSync, or handleNewFromGfileSync.

## newFromData

Arguments

 :: (HasCallStack, MonadIO m) => ByteString data: The SVG data -> m (Maybe Handle) Returns: A Handle or NULL if an error occurs. (Can throw GError)

Loads the SVG specified by data. Note that this function creates an Handle without a base URL, and without any [flagsrsvg.HandleFlags]. If you need these, use handleNewFromStreamSync instead by creating a MemoryInputStream from your data.

Since: 2.14

## newFromFile

Arguments

 :: (HasCallStack, MonadIO m) => Text filename: The file name to load, or a URI. -> m (Maybe Handle) Returns: A Handle or NULL if an error occurs. (Can throw GError)

Loads the SVG specified by fileName. Note that this function, like handleNew, does not specify any loading flags for the resulting handle. If you require the use of [flagsrsvg.HandleFlags], use handleNewFromGfileSync.

Since: 2.14

## newFromGfileSync

Arguments

 :: (HasCallStack, MonadIO m, IsFile a, IsCancellable b) => a file: a GFile -> [HandleFlags] flags: flags from [flagsrsvg.HandleFlags] -> Maybe b cancellable: a GCancellable, or NULL -> m (Maybe Handle) Returns: a new Handle on success, or NULL with error filled in (Can throw GError)

Creates a new Handle for file.

This function sets the "base file" of the handle to be file itself, so SVG elements like <image> which reference external resources will be resolved relative to the location of file.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned in error.

Since: 2.32

## newFromStreamSync

Arguments

 :: (HasCallStack, MonadIO m, IsInputStream a, IsFile b, IsCancellable c) => a inputStream: a GInputStream -> Maybe b baseFile: a GFile, or NULL -> [HandleFlags] flags: flags from [flagsrsvg.HandleFlags] -> Maybe c cancellable: a GCancellable, or NULL -> m (Maybe Handle) Returns: a new Handle on success, or NULL with error filled in (Can throw GError)

Creates a new Handle for stream.

This function sets the "base file" of the handle to be baseFile if provided. SVG elements like <image> which reference external resources will be resolved relative to the location of baseFile.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned in error.

Since: 2.32

## newWithFlags

Arguments

 :: (HasCallStack, MonadIO m) => [HandleFlags] flags: flags from [flagsrsvg.HandleFlags] -> m Handle Returns: a new Handle

Creates a new Handle with flags flags. After calling this function, you can feed the resulting handle with SVG data by using handleReadStreamSync.

Since: 2.36

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a, IsInputStream b, IsCancellable c) => a handle: a Handle -> b stream: a GInputStream -> Maybe c cancellable: a GCancellable, or NULL -> m () (Can throw GError)

Reads stream and writes the data from it to handle.

Before calling this function, you may need to call handleSetBaseUri or handleSetBaseGfile to set the "base file" for resolving references to external resources. SVG elements like <image> which reference external resources will be resolved relative to the location you specify with those functions.

If cancellable is not NULL, then the operation can be cancelled by triggering the cancellable object from another thread. If the operation was cancelled, the error G_IO_ERROR_CANCELLED will be returned.

Since: 2.32

## renderCairo

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> Context cr: A Cairo context -> m Bool Returns: TRUE if drawing succeeded; FALSE otherwise.

Deprecated: (Since version 2.52.)Please use handleRenderDocument instead; that function letsyou pass a viewport and obtain a good error message.

Draws a loaded SVG handle to a Cairo context. Please try to use handleRenderDocument instead, which allows you to pick the size at which the document will be rendered.

Historically this function has picked a size by itself, based on the following rules:

• If the SVG document has both width and height attributes with physical units (px, in, cm, mm, pt, pc) or font-based units (em, ex), the function computes the size directly based on the dots-per-inch (DPI) you have configured with handleSetDpi. This is the same approach as handleGetIntrinsicSizeInPixels.
• Otherwise, if there is a viewBox attribute and both width and height are set to 100% (or if they don't exist at all and thus default to 100%), the function uses the width and height of the viewBox as a pixel size. This produces a rendered document with the correct aspect ratio.
• Otherwise, this function computes the extents of every graphical object in the SVG document to find the total extents. This is moderately expensive, but no more expensive than rendering the whole document, for example.
• This function cannot deal with percentage-based units for width and height because there is no viewport against which they could be resolved; that is why it will compute the extents of objects in that case. This is why we recommend that you use handleRenderDocument instead, which takes in a viewport and follows the sizing policy from the web platform.

Drawing will occur with respect to the cr's current transformation: for example, if the cr has a rotated current transformation matrix, the whole SVG will be rotated in the rendered version.

This function depends on the Handle's DPI to compute dimensions in pixels, so you should call handleSetDpi beforehand.

Note that cr must be a Cairo context that is not in an error state, that is, cairo_status() must return CAIRO_STATUS_SUCCESS for it. Cairo can set a context to be in an error state in various situations, for example, if it was passed an invalid matrix or if it was created for an invalid surface.

Since: 2.14

## renderCairoSub

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> Context cr: A Cairo context -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to render the whole SVG. -> m Bool Returns: TRUE if drawing succeeded; FALSE otherwise.

Deprecated: (Since version 2.52.)Please use handleRenderLayer instead; that function letsyou pass a viewport and obtain a good error message.

Renders a single SVG element in the same place as for a whole SVG document (a "subset" of the document). Please try to use handleRenderLayer instead, which allows you to pick the size at which the document with the layer will be rendered.

This is equivalent to handleRenderCairo, but it renders only a single element and its children, as if they composed an individual layer in the SVG.

Historically this function has picked a size for the whole document by itself, based on the following rules:

• If the SVG document has both width and height attributes with physical units (px, in, cm, mm, pt, pc) or font-based units (em, ex), the function computes the size directly based on the dots-per-inch (DPI) you have configured with handleSetDpi. This is the same approach as handleGetIntrinsicSizeInPixels.
• Otherwise, if there is a viewBox attribute and both width and height are set to 100% (or if they don't exist at all and thus default to 100%), the function uses the width and height of the viewBox as a pixel size. This produces a rendered document with the correct aspect ratio.
• Otherwise, this function computes the extents of every graphical object in the SVG document to find the total extents. This is moderately expensive, but no more expensive than rendering the whole document, for example.
• This function cannot deal with percentage-based units for width and height because there is no viewport against which they could be resolved; that is why it will compute the extents of objects in that case. This is why we recommend that you use handleRenderLayer instead, which takes in a viewport and follows the sizing policy from the web platform.

Drawing will occur with respect to the cr's current transformation: for example, if the cr has a rotated current transformation matrix, the whole SVG will be rotated in the rendered version.

This function depends on the Handle's DPI to compute dimensions in pixels, so you should call handleSetDpi beforehand.

Note that cr must be a Cairo context that is not in an error state, that is, cairo_status() must return CAIRO_STATUS_SUCCESS for it. Cairo can set a context to be in an error state in various situations, for example, if it was passed an invalid matrix or if it was created for an invalid surface.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

Since: 2.14

## renderDocument

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Context cr: A Cairo context -> Rectangle viewport: Viewport size at which the whole SVG would be fitted. -> m () (Can throw GError)

Renders the whole SVG document fitted to a viewport.

The viewport gives the position and size at which the whole SVG document will be rendered. The document is scaled proportionally to fit into this viewport.

The cr must be in a CAIRO_STATUS_SUCCESS state, or this function will not render anything, and instead will return an error.

Since: 2.46

## renderElement

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Context cr: A Cairo context -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to render the whole SVG document tree. -> Rectangle elementViewport: Viewport size in which to fit the element -> m () (Can throw GError)

Renders a single SVG element to a given viewport.

This function can be used to extract individual element subtrees and render them, scaled to a given elementViewport. This is useful for applications which have reusable objects in an SVG and want to render them individually; for example, an SVG full of icons that are meant to be be rendered independently of each other.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

You can pass NULL for the id if you want to render all the elements in the SVG, i.e. to render everything from the root element.

The element_viewport gives the position and size at which the named element will be rendered. FIXME: mention proportional scaling.

Since: 2.46

## renderLayer

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Context cr: A Cairo context -> Maybe Text id: An element's id within the SVG, starting with "#" (a single hash character), for example, #layer1. This notation corresponds to a URL's fragment ID. Alternatively, pass NULL to render the whole SVG document tree. -> Rectangle viewport: Viewport size at which the whole SVG would be fitted. -> m () (Can throw GError)

Renders a single SVG element in the same place as for a whole SVG document.

The viewport gives the position and size at which the whole SVG document would be rendered. The document is scaled proportionally to fit into this viewport; hence the individual layer may be smaller than this.

This is equivalent to handleRenderDocument, but it renders only a single element and its children, as if they composed an individual layer in the SVG. The element is rendered with the same transformation matrix as it has within the whole SVG document. Applications can use this to re-render a single element and repaint it on top of a previously-rendered document, for example.

Element IDs should look like an URL fragment identifier; for example, pass #foo (hash foo) to get the geometry of the element that has an id="foo" attribute.

You can pass NULL for the id if you want to render all the elements in the SVG, i.e. to render everything from the root element.

Since: 2.46

## setBaseGfile

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a, IsFile b) => a handle: a Handle -> b baseFile: a GFile -> m ()

Set the base URI for handle from file.

Note: This function may only be called before handleWrite or handleReadStreamSync have been called.

Since: 2.32

## setBaseUri

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle -> Text baseUri: The base uri -> m ()

Set the base URI for this SVG.

Note: This function may only be called before handleWrite or handleReadStreamSync have been called.

Since: 2.9

## setDpi

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Double dpi: Dots Per Inch (i.e. as Pixels Per Inch) -> m ()

Sets the DPI at which the handle will be rendered. 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, but since setDefaultDpi is deprecated, please do not pass values <= 0 to this function.

Since: 2.8

## setDpiXY

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Double dpiX: Dots Per Inch (i.e. Pixels Per Inch) -> Double dpiY: Dots Per Inch (i.e. Pixels Per Inch) -> m ()

Sets the DPI at which the handle will be rendered. 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, but since setDefaultDpiXY is deprecated, please do not pass values <= 0 to this function.

Since: 2.8

## setSizeCallback

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: An Handle -> Maybe SizeFunc sizeFunc: A sizing function, or NULL -> m ()

Deprecated: (Since version 2.14.)Use handleRenderDocument instead.This function was deprecated because when the sizeFunc is used, it makes itunclear when the librsvg functions which call the sizeFunc will use thesize computed originally, or the callback-specified size, or whether itrefers to the whole SVG or to just a sub-element of it. It is easier, andunambiguous, to use code similar to the example above.

Sets the sizing function for the handle, which can be used to override the size that librsvg computes for SVG images. The sizeFunc is called from the following functions:

• handleGetDimensions
• handleGetDimensionsSub
• handleGetPositionSub
• handleRenderCairo
• handleRenderCairoSub

Librsvg computes the size of the SVG being rendered, and passes it to the sizeFunc, which may then modify these values to set the final size of the generated image.

## setStylesheet

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: A Handle. -> ByteString css: String with CSS data; must be valid UTF-8. -> m () (Can throw GError)

Sets a CSS stylesheet to use for an SVG document.

The cssLen argument is mandatory; this function will not compute the length of the css string. This is because a provided stylesheet, which the calling program could read from a file, can have nul characters in it.

During the CSS cascade, the specified stylesheet will be used with a "User" origin.

Note that @import rules will not be resolved, except for data: URLs.

Since: 2.48

## write

Arguments

 :: (HasCallStack, MonadIO m, IsHandle a) => a handle: an Handle -> ByteString buf: pointer to svg data -> m () (Can throw GError)

Deprecated: (Since version 2.46.)Use handleReadStreamSync or the constructorfunctions handleNewFromGfileSync orhandleNewFromStreamSync. This function is deprecated because itwill accumulate data from the buf in memory until handleClose getscalled. To avoid a big temporary buffer, use the suggested functions, whichtake a GFile or a GInputStream and do not require a temporary buffer.

Loads the next count bytes of the image. You can call this function multiple times until the whole document is consumed; then you must call handleClose to actually parse the document.

Before calling this function for the first time, you may need to call handleSetBaseUri or handleSetBaseGfile to set the "base file" for resolving references to external resources. SVG elements like <image> which reference external resources will be resolved relative to the location you specify with those functions.

# Properties

## baseUri

Base URI, to be used to resolve relative references for resources. See the section "Security and locations of referenced files" for details.

constructHandleBaseUri :: (IsHandle o, MonadIO m) => Text -> m (GValueConstruct o) Source #

Construct a GValueConstruct with valid value for the “base-uri” property. This is rarely needed directly, but it is used by new.

getHandleBaseUri :: (MonadIO m, IsHandle o) => o -> m Text Source #

Get the value of the “base-uri” property. When overloading is enabled, this is equivalent to

get handle #baseUri


setHandleBaseUri :: (MonadIO m, IsHandle o) => o -> Text -> m () Source #

Set the value of the “base-uri” property. When overloading is enabled, this is equivalent to

set handle [ #baseUri := value ]


## desc

SVG's description.

getHandleDesc :: (MonadIO m, IsHandle o) => o -> m (Maybe Text) Source #

Get the value of the “desc” property. When overloading is enabled, this is equivalent to

get handle #desc


## dpiX

Horizontal resolution in dots per inch.

constructHandleDpiX :: (IsHandle o, MonadIO m) => Double -> m (GValueConstruct o) Source #

Construct a GValueConstruct with valid value for the “dpi-x” property. This is rarely needed directly, but it is used by new.

getHandleDpiX :: (MonadIO m, IsHandle o) => o -> m Double Source #

Get the value of the “dpi-x” property. When overloading is enabled, this is equivalent to

get handle #dpiX


setHandleDpiX :: (MonadIO m, IsHandle o) => o -> Double -> m () Source #

Set the value of the “dpi-x” property. When overloading is enabled, this is equivalent to

set handle [ #dpiX := value ]


## dpiY

Horizontal resolution in dots per inch.

constructHandleDpiY :: (IsHandle o, MonadIO m) => Double -> m (GValueConstruct o) Source #

Construct a GValueConstruct with valid value for the “dpi-y” property. This is rarely needed directly, but it is used by new.

getHandleDpiY :: (MonadIO m, IsHandle o) => o -> m Double Source #

Get the value of the “dpi-y” property. When overloading is enabled, this is equivalent to

get handle #dpiY


setHandleDpiY :: (MonadIO m, IsHandle o) => o -> Double -> m () Source #

Set the value of the “dpi-y” property. When overloading is enabled, this is equivalent to

set handle [ #dpiY := value ]


## em

Exact width, in pixels, of the rendered SVG before calling the size callback as specified by handleSetSizeCallback.

getHandleEm :: (MonadIO m, IsHandle o) => o -> m Double Source #

Get the value of the “em” property. When overloading is enabled, this is equivalent to

get handle #em


## ex

Exact height, in pixels, of the rendered SVG before calling the size callback as specified by handleSetSizeCallback.

getHandleEx :: (MonadIO m, IsHandle o) => o -> m Double Source #

Get the value of the “ex” property. When overloading is enabled, this is equivalent to

get handle #ex


## flags

Flags from [flagsrsvg.HandleFlags].

Since: 2.36

constructHandleFlags :: (IsHandle o, MonadIO m) => [HandleFlags] -> m (GValueConstruct o) Source #

Construct a GValueConstruct with valid value for the “flags” property. This is rarely needed directly, but it is used by new.

getHandleFlags :: (MonadIO m, IsHandle o) => o -> m [HandleFlags] Source #

Get the value of the “flags” property. When overloading is enabled, this is equivalent to

get handle #flags


## height

Height, in pixels, of the rendered SVG after calling the size callback as specified by handleSetSizeCallback.

getHandleHeight :: (MonadIO m, IsHandle o) => o -> m Int32 Source #

Get the value of the “height” property. When overloading is enabled, this is equivalent to

get handle #height


getHandleMetadata :: (MonadIO m, IsHandle o) => o -> m (Maybe Text) Source #

Get the value of the “metadata” property. When overloading is enabled, this is equivalent to

get handle #metadata


## title

SVG's title.

getHandleTitle :: (MonadIO m, IsHandle o) => o -> m (Maybe Text) Source #

Get the value of the “title” property. When overloading is enabled, this is equivalent to

get handle #title


## width

Width, in pixels, of the rendered SVG after calling the size callback as specified by handleSetSizeCallback.

getHandleWidth :: (MonadIO m, IsHandle o) => o -> m Int32 Source #

Get the value of the “width” property. When overloading is enabled, this is equivalent to

get handle #width