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Gdk::PixbufLoader Class Reference

Inheritance diagram for Gdk::PixbufLoader:

List of all members.

Public Member Functions

void close ()
 Informs a pixbuf loader that no further writes with PixbufLoader::write() will occur, so that it can free its internal loading structures.
Glib::RefPtr
<Gdk::PixbufAnimation
get_animation ()
 Queries the Gdk::PixbufAnimation that a pixbuf loader is currently creating.
PixbufFormat get_format () const
 Obtains the available information about the format of the currently loading image file.
Glib::RefPtr<Gdk::Pixbufget_pixbuf ()
 Queries the Gdk::Pixbuf that a pixbuf loader is currently creating.
const GdkPixbufLoader* gobj () const
 Provides access to the underlying C GObject.
GdkPixbufLoader* gobj ()
 Provides access to the underlying C GObject.
GdkPixbufLoader* gobj_copy ()
 Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.
void set_size (int width, int height)
 Causes the image to be scaled while it is loaded.
Glib::SignalProxy0<void> signal_area_prepared ()
 This signal is emitted when the pixbuf loader has allocated the pixbuf in the desired size.
Glib::SignalProxy4< void, int,
int, int, int > 
signal_area_updated ()
 This signal is emitted when a significant area of the image being loaded has been updated.
Glib::SignalProxy0<void> signal_closed ()
 This signal is emitted when close() is called.
Glib::SignalProxy2< void, int,
int > 
signal_size_prepared ()
 This signal is emitted when the pixbuf loader has been fed the initial amount of data that is required to figure out the size of the image that it will create.
void write (const guint8* buf, gsize count)
 Causes the pixbuf loader to parse the next count bytes of an image.
virtual ~PixbufLoader ()

Static Public Member Functions

static Glib::RefPtr<PixbufLoadercreate (const Glib::ustring& image_type, bool mime_type=false)
 Constructs a pixbuf loader object for a specific image type.
static Glib::RefPtr<PixbufLoadercreate ()
 Creates a new pixbuf loader object.

Protected Member Functions

virtual void on_area_prepared ()
virtual void on_area_updated (int x, int y, int width, int height)
virtual void on_closed ()
 PixbufLoader (const Glib::ustring& image_type, bool mime_type=false)
 Constructs a pixbuf loader object for a specific image type.
 PixbufLoader ()
 Constructs a pixbuf loader object.

Related Functions

(Note that these are not member functions.)

Glib::RefPtr<Gdk::PixbufLoaderwrap (GdkPixbufLoader* object, bool take_copy=false)
 A Glib::wrap() method for this object.


Constructor & Destructor Documentation

virtual Gdk::PixbufLoader::~PixbufLoader (  )  [virtual]

Gdk::PixbufLoader::PixbufLoader (  )  [protected]

Constructs a pixbuf loader object.

Gdk::PixbufLoader::PixbufLoader ( const Glib::ustring image_type,
bool  mime_type = false 
) [explicit, protected]

Constructs a pixbuf loader object for a specific image type.

Constructs a new pixbuf loader object that always attempts to parse image data as if it were an image of type image_type, instead of identifying the type automatically. Useful if you want an error if the image isn't the expected type, for loading image formats that can't be reliably identified by looking at the data, or if the user manually forces a specific type.

The image_type can be one of the types returned by Gdk::Pixbuf::get_formats(), or a MIME type.

Common MIME Types are listed here http://www.iana.org/assignments/media-types/ and here: http://www.freedesktop.org/Software/shared-mime-info

The list of non-mime-type image formats depends on what image loaders are installed, but typically "png", "jpeg", "gif", "tiff" and "xpm" are among the supported formats. To obtain the full list of supported image formats, call PixbufFormat::get_name() on each of the PixbufFormats returned by Gdk::Pixbuf::get_formats().

Parameters:
image_type Name of the image format to be loaded with the image.
mime_type If this is true then the image_type is a MIME type.
Exceptions:
Gdk::PixbufError 


Member Function Documentation

void Gdk::PixbufLoader::close (  ) 

Informs a pixbuf loader that no further writes with PixbufLoader::write() will occur, so that it can free its internal loading structures.

Also, tries to parse any data that hasn't yet been parsed; if the remaining data is partial or corrupt, an exception will be thrown. If you're just cancelling a load rather than expecting it to be finished, writing an empty catch() block to ignore errors is reasonable.

Exceptions:
Gdk::PixbufError 
Glib::FileError Informs a pixbuf loader that no further writes with write() will occur, so that it can free its internal loading structures. Also, tries to parse any data that hasn't yet been parsed; if the remaining data is partial or corrupt, an error will be returned. If false is returned, error will be set to an error from the Gdk::PIXBUF_ERROR or FILE_ERROR domains. If you're just cancelling a load rather than expecting it to be finished, passing 0 for error to ignore it is reasonable.
Returns:
true if all image data written so far was successfully passed out via the update_area signal.

static Glib::RefPtr<PixbufLoader> Gdk::PixbufLoader::create ( const Glib::ustring image_type,
bool  mime_type = false 
) [static]

Constructs a pixbuf loader object for a specific image type.

Constructs a new pixbuf loader object that always attempts to parse image data as if it were an image of type image_type, instead of identifying the type automatically. Useful if you want an error if the image isn't the expected type, for loading image formats that can't be reliably identified by looking at the data, or if the user manually forces a specific type.

The image_type can be one of the types returned by Gdk::Pixbuf::get_formats(), or a MIME type.

Common MIME Types are listed here http://www.iana.org/assignments/media-types/ and here: http://www.freedesktop.org/Software/shared-mime-info

The list of non-mime-type image formats depends on what image loaders are installed, but typically "png", "jpeg", "gif", "tiff" and "xpm" are among the supported formats. To obtain the full list of supported image formats, call PixbufFormat::get_name() on each of the PixbufFormats returned by Gdk::Pixbuf::get_formats().

Parameters:
image_type Name of the image format to be loaded with the image.
mime_type If this is true then the image_type is a MIME type.
Exceptions:
Gdk::PixbufError 

static Glib::RefPtr<PixbufLoader> Gdk::PixbufLoader::create (  )  [static]

Creates a new pixbuf loader object.

Returns:
A newly-created pixbuf loader.

Glib::RefPtr<Gdk::PixbufAnimation> Gdk::PixbufLoader::get_animation (  ) 

Queries the Gdk::PixbufAnimation that a pixbuf loader is currently creating.

In general it only makes sense to call this function after the "area_prepared" signal has been emitted by the loader. If the loader doesn't have enough bytes yet (hasn't emitted the "area_prepared" signal) this function will return 0.

Returns:
The Gdk::PixbufAnimation that the loader is loading, or 0 if not enough data has been read to determine the information.

PixbufFormat Gdk::PixbufLoader::get_format (  )  const

Obtains the available information about the format of the currently loading image file.

Returns:
A Gdk::PixbufFormat or 0. The return value is owned by GdkPixbuf and should not be freed.
Since gtkmm 2.2:

Glib::RefPtr<Gdk::Pixbuf> Gdk::PixbufLoader::get_pixbuf (  ) 

Queries the Gdk::Pixbuf that a pixbuf loader is currently creating.

In general it only makes sense to call this function after the "area_prepared" signal has been emitted by the loader; this means that enough data has been read to know the size of the image that will be allocated. If the loader has not received enough data via write(), then this function returns 0. The returned pixbuf will be the same in all future calls to the loader, so simply calling Glib::object_ref() should be sufficient to continue using it. Additionally, if the loader is an animation, it will return the "static image" of the animation (see Gdk::PixbufAnimation::get_static_image()).

Returns:
The Gdk::Pixbuf that the loader is creating, or 0 if not enough data has been read to determine how to create the image buffer.

const GdkPixbufLoader* Gdk::PixbufLoader::gobj (  )  const [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

GdkPixbufLoader* Gdk::PixbufLoader::gobj (  )  [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

GdkPixbufLoader* Gdk::PixbufLoader::gobj_copy (  ) 

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

virtual void Gdk::PixbufLoader::on_area_prepared (  )  [protected, virtual]

virtual void Gdk::PixbufLoader::on_area_updated ( int  x,
int  y,
int  width,
int  height 
) [protected, virtual]

virtual void Gdk::PixbufLoader::on_closed (  )  [protected, virtual]

void Gdk::PixbufLoader::set_size ( int  width,
int  height 
)

Causes the image to be scaled while it is loaded.

The desired image size can be determined relative to the original size of the image by calling set_size() from a signal handler for the size_prepared signal.

Attempts to set the desired image size are ignored after the emission of the size_prepared signal.

Since gtkmm 2.2:
Parameters:
width The desired width of the image being loaded.
height The desired height of the image being loaded.

Glib::SignalProxy0< void > Gdk::PixbufLoader::signal_area_prepared (  ) 

This signal is emitted when the pixbuf loader has allocated the pixbuf in the desired size.

After this signal is emitted, applications can call get_pixbuf() to fetch the partially-loaded pixbuf.

Prototype:
void on_my_area_prepared()

Glib::SignalProxy4< void,int,int,int,int > Gdk::PixbufLoader::signal_area_updated (  ) 

This signal is emitted when a significant area of the image being loaded has been updated.

Normally it means that a complete scanline has been read in, but it could be a different area as well. Applications can use this signal to know when to repaint areas of an image that is being loaded.

Parameters:
X offset of upper-left corner of the updated area.
y Y offset of upper-left corner of the updated area.
width Width of updated area.
height Height of updated area.
Prototype:
void on_my_area_updated(int x, int y, int width, int height)

Glib::SignalProxy0< void > Gdk::PixbufLoader::signal_closed (  ) 

This signal is emitted when close() is called.

It can be used by different parts of an application to receive notification when an image loader is closed by the code that drives it.

Prototype:
void on_my_closed()

Glib::SignalProxy2< void,int,int > Gdk::PixbufLoader::signal_size_prepared (  ) 

This signal is emitted when the pixbuf loader has been fed the initial amount of data that is required to figure out the size of the image that it will create.

Applications can call set_size() in response to this signal to set the desired size to which the image should be scaled.

Parameters:
width The original width of the image.
height The original height of the image
Prototype:
void on_my_size_prepared(int width, int height)

void Gdk::PixbufLoader::write ( const guint8 *  buf,
gsize  count 
)

Causes the pixbuf loader to parse the next count bytes of an image.

It will return if the data was loaded successfully, and throw an exception if an error occurred. In the latter case, the loader will be closed, and will not accept further writes.

Parameters:
buf Pointer to image data.
count Length of the buf buffer in bytes.
Exceptions:
Gdk::PixbufError 
Glib::FileError This will cause a pixbuf loader to parse the next count bytes of an image. It will return true if the data was loaded successfully, 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 Gdk::PIXBUF_ERROR or FILE_ERROR domains.
Parameters:
buf Pointer to image data.
count Length of the buf buffer in bytes.
Returns:
true if the write was successful, or false if the loader cannot parse the buffer.


Friends And Related Function Documentation

Glib::RefPtr<Gdk::PixbufLoader> wrap ( GdkPixbufLoader *  object,
bool  take_copy = false 
) [related]

A Glib::wrap() method for this object.

Parameters:
object The C instance.
take_copy False if the result should take ownership of the C instance. True if it should take a new copy or ref.
Returns:
A C++ instance that wraps this C instance.


The documentation for this class was generated from the following file:

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