GdkPixbufLoader Application-driven progressive image loading. #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() 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, just create a new one, 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 two important signals throughout the process. The first, "area_prepared", will be called as soon as the image has enough information to determine the size of the image to be used. It will pass a @GdkPixbuf in. If you want to use it, you can simply ref it. In addition, no actual information will be passed in yet, so the pixbuf can be safely filled with any temporary graphics (or an initial color) as needed. You can also call the gdk_pixbuf_loader_get_pixbuf() once this signal has been emitted and get the same pixbuf. The other signal, "area_updated" gets called 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 area updated. For example, in an interlaced image, you need to make several passes before the image is done loading. Loading an animation is a little more complex then loading an image. In addition to the above signals, there is also a "frame_done" signal, as well as an "animation_done" signal. The first lets the application know that it is dealing with an animation, instead of a static image. It also passes a #GdkPixbufFrame in the signal. As before, if you want to keep the frame, you need to ref it. Once the first "frame_done" signal has been emitted, you can call gdk_pixbuf_loader_get_animation() to get the #GdkPixbufAnimation struct. Each subsequent frame goes through a similar lifecycle. For example "area_prepared" is re-emitted. Then "area_updated" is emitted as many times as necessary. Finally, "animation_done" is emitted as soon as all frames are done. gdk_pixbuf_new_from_file() Casts a #GtkObject to a #GdkPixbufLoader. @obj: A GTK+ object. @Returns: @loader: @buf: @count: @Returns: @loader: @Returns: @loader: @Returns: @loader: 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. @loader: Loader which emitted the signal. @x: 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. This signal is emitted when the pixbuf loader has been fed the initial amount of data that is required to figure out the size and format of the image that it will create. After this signal is emitted, applications can call gdk_pixbuf_loader_get_pixbuf() to fetch the partially-loaded pixbuf. @loader: Loader which emitted the signal. This signal is emitted when a frame is done loading. It will be emitted for each frame in an animation data stream. @loader: Loader which emitted the signal. @frame: Frame which just completed loading. This signal is emitted when an animation is done loading. @loader: Loader which emitted the signal. This signal is emitted when gdk_pixbuf_loader_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. @loader: Loader which emitted the signal.