Commit 0e86d280 authored by Jonathan Blandford's avatar Jonathan Blandford Committed by Jonathan Blandford
Browse files

much longer long description added.

2000-01-07  Jonathan Blandford  <jrb@redhat.com>

	* doc/tmpl/gdk-pixbuf-loader.sgml: much longer long description
	added.
parent 4bd671a8
......@@ -22,11 +22,11 @@ Animations as multi-frame structures.
<para>
Each animation frame can have several things happen to it when the
next frame is displayed. The #GdkPixbufFrameAction determines this.
If a frame as marked as @GDK_PIXBUF_FRAME_RETAIN, then the image
If a frame as marked as #GDK_PIXBUF_FRAME_RETAIN, then the image
will remain displayed, and will be potentially occluded by the next
frame. If it is marked as @GDK_PIXBUF_FRAME_DISPOSE, then the
frame. If it is marked as #GDK_PIXBUF_FRAME_DISPOSE, then the
animation is reverted to the setting before the frame was shown. If
it is marked as @GDK_PIXBUF_FRAME_REVERT, then the animation is
it is marked as #GDK_PIXBUF_FRAME_REVERT, then the animation is
reverted to the first image before continuing.
</para>
......
......@@ -2,17 +2,58 @@
GdkPixbufLoader
<!-- ##### SECTION Short_Description ##### -->
Application-driven image loading.
Application-driven progressive image loading.
<!-- ##### SECTION Long_Description ##### -->
<para>
#GdkPixbufLoader provides a way for applications to drive the
process of loading an image. Applications can use this
functionality instead of gdk_pixbuf_new_from_file() when they need
to parse image data in small chunks, such as when reading it from
a network connection.
process of loading an image, by letting them send the image data
directly. 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.
</para>
<para>
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.
</para>
<para>
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.
</para>
<refsect2>
<title>Loading an animation</title>
<para>
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.
</para>
</refsect2>
<!-- ##### SECTION See_Also ##### -->
<para>
gdk_pixbuf_new_from_file()
......
2000-01-07 Jonathan Blandford <jrb@redhat.com>
* doc/tmpl/gdk-pixbuf-loader.sgml: much longer long description
added.
2000-01-05 Owen Taylor <otaylor@redhat.com>
* gdk-pixbuf/pixops/pixops.c (pixops_process): Fix computation of end of run indices.
......
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