gtkmm: Gdk::PixbufLoader Class Reference

#include <gdkmm/pixbufloader.h>

Inheritance diagram for Gdk::PixbufLoader:

Public Member Functions

 PixbufLoader (PixbufLoader&& src) noexcept
 
PixbufLoaderoperator= (PixbufLoader&& src) noexcept
 
 ~PixbufLoader () noexceptoverride
 
GdkPixbufLoader* gobj ()
 Provides access to the underlying C GObject. More...

 
const GdkPixbufLoader* gobj () const
 Provides access to the underlying C GObject. More...

 
GdkPixbufLoader* gobj_copy ()
 Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs. More...

 
void set_size (int width, int height)
 Causes the image to be scaled while it is loaded. More...

 
void write (const guint8* buf, gsize count)
 Causes the pixbuf loader to parse the next count bytes of an image. More...

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

 
Glib::RefPtr< Gdk::Pixbufget_pixbuf ()
 Queries the Gdk::Pixbuf that a pixbuf loader is currently creating. More...

 
Glib::RefPtr< Gdk::PixbufAnimationget_animation ()
 Queries the Gdk::PixbufAnimation that a pixbuf loader is currently creating. More...

 
PixbufFormat get_format () const
 Obtains the available information about the format of the currently loading image file. More...

 
Glib::SignalProxy< void > signal_area_prepared ()
 This signal is emitted when the pixbuf loader has allocated the pixbuf in the desired size. More...

 
Glib::SignalProxy< void, int, int, int, int > signal_area_updated ()
 This signal is emitted when a significant area of the image being loaded has been updated. More...

 
Glib::SignalProxy< void > signal_closed ()
 This signal is emitted when close() is called. More...

 
Glib::SignalProxy< 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. More...

 
- Public Member Functions inherited from Glib::Object
 Object (const Object &)=delete
 
Objectoperator= (const Object &)=delete
 
 Object (Object &&src) noexcept
 
Objectoperator= (Object &&src) noexcept
 
void * get_data (const QueryQuark &key)
 
void set_data (const Quark &key, void *data)
 
void set_data (const Quark &key, void *data, DestroyNotify notify)
 
void remove_data (const QueryQuark &quark)
 
void * steal_data (const QueryQuark &quark)
 
Glib::RefPtr< Glib::Objectwrap (GObject *object, bool take_copy=false)
 
- Public Member Functions inherited from Glib::ObjectBase
 ObjectBase (const ObjectBase &)=delete
 
ObjectBaseoperator= (const ObjectBase &)=delete
 
void set_property_value (const Glib::ustring &property_name, const Glib::ValueBase &value)
 
void get_property_value (const Glib::ustring &property_name, Glib::ValueBase &value) const
 
void set_property (const Glib::ustring &property_name, const PropertyType &value)
 
void get_property (const Glib::ustring &property_name, PropertyType &value) const
 
void connect_property_changed (const Glib::ustring &property_name, const sigc::slot< void > &slot)
 
void connect_property_changed (const Glib::ustring &property_name, sigc::slot< void > &&slot)
 
sigc::connection connect_property_changed_with_return (const Glib::ustring &property_name, const sigc::slot< void > &slot)
 
sigc::connection connect_property_changed_with_return (const Glib::ustring &property_name, sigc::slot< void > &&slot)
 
void freeze_notify ()
 
void thaw_notify ()
 
virtual void reference () const
 
virtual void unreference () const
 
GObject * gobj ()
 
const GObject * gobj () const
 
GObject * gobj_copy () const
 
- Public Member Functions inherited from sigc::trackable
 trackable () noexcept
 
 trackable (const trackable &src) noexcept
 
 trackable (trackable &&src)
 
 ~trackable ()
 
void add_destroy_notify_callback (void *data, func_destroy_notify func) const
 
void notify_callbacks ()
 
trackableoperator= (const trackable &src)
 
trackableoperator= (trackable &&src)
 
void remove_destroy_notify_callback (void *data) const
 

Static Public Member Functions

static GType get_type ()
 Get the GType for this class, for use with the underlying GObject type system. More...

 
static Glib::RefPtr< PixbufLoadercreate ()
 Creates a new pixbuf loader object. More...

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

 

Protected Member Functions

 PixbufLoader ()
 Constructs a pixbuf loader object. More...

 
 PixbufLoader (const Glib::ustring& image_type, bool mime_type=false)
 Constructs a pixbuf loader object for a specific image type. More...

 
virtual void on_area_prepared ()
 This is a default handler for the signal signal_area_prepared(). More...

 
virtual void on_area_updated (int x, int y, int width, int height)
 This is a default handler for the signal signal_area_updated(). More...

 
virtual void on_closed ()
 This is a default handler for the signal signal_closed(). More...

 
virtual void on_size_prepared (int width, int height)
 This is a default handler for the signal signal_size_prepared(). More...

 
- Protected Member Functions inherited from Glib::Object
 Object ()
 
 Object (const Glib::ConstructParams &construct_params)
 
 Object (GObject *castitem)
 
 ~Object () noexceptoverride
 
- Protected Member Functions inherited from Glib::ObjectBase
 ObjectBase ()
 
 ObjectBase (const char *custom_type_name)
 
 ObjectBase (const std::type_info &custom_type_info)
 
 ObjectBase (ObjectBase &&src) noexcept
 
ObjectBaseoperator= (ObjectBase &&src) noexcept
 
virtual ~ObjectBase () noexcept=0
 
void initialize (GObject *castitem)
 
void initialize_move (GObject *castitem, Glib::ObjectBase *previous_wrapper)
 

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. More...

 

Additional Inherited Members

- Public Types inherited from Glib::Object
typedef void(*)(gpointer data DestroyNotify)
 
- Public Types inherited from sigc::trackable
typedef internal::func_destroy_notify func_destroy_notify
 

Constructor & Destructor Documentation

Gdk::PixbufLoader::PixbufLoader ( PixbufLoader&&  src)
noexcept
Gdk::PixbufLoader::~PixbufLoader ( )
overridenoexcept
Gdk::PixbufLoader::PixbufLoader ( )
protected

Constructs a pixbuf loader object.

Gdk::PixbufLoader::PixbufLoader ( const Glib::ustring image_type,
bool  mime_type = false 
)
explicitprotected

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_typeName of the image format to be loaded with the image.
mime_typeIf 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
static Glib::RefPtr<PixbufLoader> Gdk::PixbufLoader::create ( )
static

Creates a new pixbuf loader object.

Returns
A newly-created pixbuf loader.
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_typeName of the image format to be loaded with the image.
mime_typeIf this is true then the image_type is a MIME type.
Exceptions
Gdk::PixbufError
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 nullptr.

Returns
The Gdk::PixbufAnimation that the loader is loading, or nullptr 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.

Since gtkmm 2.2:
Returns
A Gdk::PixbufFormat or nullptr. The return value is owned by GdkPixbuf and should not be freed.
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 nullptr. 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 nullptr if not enough data has been read to determine how to create the image buffer.
static GType Gdk::PixbufLoader::get_type ( )
static

Get the GType for this class, for use with the underlying GObject type system.

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

Provides access to the underlying C GObject.

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

Provides access to the underlying C GObject.

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 ( )
protectedvirtual

This is a default handler for the signal signal_area_prepared().

virtual void Gdk::PixbufLoader::on_area_updated ( int  x,
int  y,
int  width,
int  height 
)
protectedvirtual

This is a default handler for the signal signal_area_updated().

virtual void Gdk::PixbufLoader::on_closed ( )
protectedvirtual

This is a default handler for the signal signal_closed().

virtual void Gdk::PixbufLoader::on_size_prepared ( int  width,
int  height 
)
protectedvirtual

This is a default handler for the signal signal_size_prepared().

PixbufLoader& Gdk::PixbufLoader::operator= ( PixbufLoader&&  src)
noexcept
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 signal_size_prepared() signal.

Attempts to set the desired image size are ignored after the emission of the signal_size_prepared() signal.

Since gtkmm 2.2:
Parameters
widthThe desired width of the image being loaded.
heightThe desired height of the image being loaded.
Glib::SignalProxy< 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.

Slot Prototype:
void on_my_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 Gdk::PixbufLoader::get_pixbuf() to fetch the partially-loaded pixbuf.

Glib::SignalProxy< 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
Xoffset of upper-left corner of the updated area.
yY offset of upper-left corner of the updated area.
widthWidth of updated area.
heightHeight of updated area.
Slot Prototype:
void on_my_area_updated(int x, int y, int width, int height)

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
xX offset of upper-left corner of the updated area.
yY offset of upper-left corner of the updated area.
widthWidth of updated area.
heightHeight of updated area.
Glib::SignalProxy< 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.

Slot Prototype:
void on_my_closed()

This signal is emitted when Gdk::PixbufLoader::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.

Glib::SignalProxy< 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
widthThe original width of the image.
heightThe original height of the image
Slot Prototype:
void on_my_size_prepared(int width, int height)

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 Gdk::PixbufLoader::set_size() in response to this signal to set the desired size to which the image should be scaled.

Parameters
widthThe original width of the image.
heightThe original height of the image.
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
bufPointer to image data.
countLength of the buf buffer in bytes.
Exceptions
Gdk::PixbufError
Glib::FileError

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
objectThe C instance.
take_copyFalse 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.