Class

GdkPixbufPixbufLoader

Description [src]

class GdkPixbuf.PixbufLoader : GObject.Object {
  /* No available fields */
}

Incremental image loader.

GdkPixbufLoader provides a way for applications to drive the process of loading an image, by letting them send the image data directly to the loader instead of having the loader read the data from a file. Applications can use this functionality instead of gdk_pixbuf_new_from_file() or gdk_pixbuf_animation_new_from_file() when they need to parse image data in small chunks. For example, it should be used when reading an image from a (potentially) slow network connection, or when loading an extremely large file.

To use GdkPixbufLoader to load an image, create a new instance, and call gdk_pixbuf_loader_write() to send the data to it. When done, gdk_pixbuf_loader_close() should be called to end the stream and finalize everything.

The loader will emit three important signals throughout the process:

  • GdkPixbufLoader::size-prepared will be emitted as soon as the image has enough information to determine the size of the image to be used. If you want to scale the image while loading it, you can call gdk_pixbuf_loader_set_size() in response to this signal.
  • GdkPixbufLoader::area-prepared will be emitted as soon as the pixbuf of the desired has been allocated. You can obtain the GdkPixbuf instance by calling gdk_pixbuf_loader_get_pixbuf(). If you want to use it, simply acquire a reference to it. You can also call gdk_pixbuf_loader_get_pixbuf() later to get the same pixbuf.
  • GdkPixbufLoader::area-updated will be emitted every time a region is updated. This way you can update a partially completed image. Note that you do not know anything about the completeness of an image from the updated area. For example, in an interlaced image you will need to make several passes before the image is done loading.

Loading an animation

Loading an animation is almost as easy as loading an image. Once the first GdkPixbufLoader::area-prepared signal has been emitted, you can call gdk_pixbuf_loader_get_animation() to get the GdkPixbufAnimation instance, and then call and gdk_pixbuf_animation_get_iter() to get a GdkPixbufAnimationIter to retrieve the pixbuf for the desired time stamp.

Ancestors

  • GObject

Constructors

gdk_pixbuf_loader_new

Creates a new pixbuf loader object.

gdk_pixbuf_loader_new_with_mime_type

Creates a new pixbuf loader object that always attempts to parse image data as if it were an image of MIME type mime_type, instead of identifying the type automatically.

Available since: 2.4

gdk_pixbuf_loader_new_with_type

Creates 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.

Instance methods

gdk_pixbuf_loader_close

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

gdk_pixbuf_loader_get_animation

Queries the GdkPixbufAnimation that a pixbuf loader is currently creating.

gdk_pixbuf_loader_get_format

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

Available since: 2.2

gdk_pixbuf_loader_get_pixbuf

Queries the GdkPixbuf that a pixbuf loader is currently creating.

gdk_pixbuf_loader_set_size

Causes the image to be scaled while it is loaded.

Available since: 2.2

gdk_pixbuf_loader_write

Parses the next count bytes in the given image buffer.

gdk_pixbuf_loader_write_bytes

Parses the next contents of the given image buffer.

Available since: 2.30

Signals

GdkPixbuf.PixbufLoader::area-prepared

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

GdkPixbuf.PixbufLoader::area-updated

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

GdkPixbuf.PixbufLoader::closed

This signal is emitted when gdk_pixbuf_loader_close() is called.

GdkPixbuf.PixbufLoader::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.

Class structure

struct GdkPixbufPixbufLoaderClass {
  GObjectClass parent_class;
  void (* size_prepared) (
    GdkPixbufLoader* loader,
    int width,
    int height
  );
  void (* area_prepared) (
    GdkPixbufLoader* loader
  );
  void (* area_updated) (
    GdkPixbufLoader* loader,
    int x,
    int y,
    int width,
    int height
  );
  void (* closed) (
    GdkPixbufLoader* loader
  );
  
}
Class members
parent_class
GObjectClass
  No description available.
size_prepared
void (* size_prepared) (
    GdkPixbufLoader* loader,
    int width,
    int height
  )
  No description available.
area_prepared
void (* area_prepared) (
    GdkPixbufLoader* loader
  )
  No description available.
area_updated
void (* area_updated) (
    GdkPixbufLoader* loader,
    int x,
    int y,
    int width,
    int height
  )
  No description available.
closed
void (* closed) (
    GdkPixbufLoader* loader
  )
  No description available.

Virtual methods

GdkPixbuf.PixbufLoaderClass.area_prepared
No description available.
GdkPixbuf.PixbufLoaderClass.area_updated
No description available.
GdkPixbuf.PixbufLoaderClass.closed
No description available.
GdkPixbuf.PixbufLoaderClass.size_prepared
No description available.