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856a93cb85
Sat Dec 22 18:18:07 2001 Owen Taylor <otaylor@redhat.com>
* gtk/Makefile.am (IGNORE_HFILES): Add gtktextutil.h
* gtk/text_widget.sgml (linkend): SGML fixes.
* gtk/gtk-sections.txt: Update
* gdk/gdk-sections.txt: Update.
* gdk/tmpl/cursors.sgml: SGML fix.
* gdk/gdk-docs.sgml: Add PNG handling magic.
96 lines
3.2 KiB
Plaintext
96 lines
3.2 KiB
Plaintext
<!-- ##### SECTION Title ##### -->
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Reference Counting and Memory Mangement
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<!-- ##### SECTION Short_Description ##### -->
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Functions for reference counting and memory management on pixbufs.
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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#GdkPixbuf structures are reference counted. This means that an
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application can share a single pixbuf among many parts of the
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code. When a piece of the program needs to keep a pointer to a
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pixbuf, it should add a reference to it by calling g_object_ref().
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When it no longer needs the pixbuf, it should subtract a reference
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by calling g_object_unref(). The pixbuf will be destroyed when
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its reference count drops to zero. Newly-created #GdkPixbuf
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structures start with a reference count of one.
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</para>
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<note>
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<para>
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As #GdkPixbuf is derived from #GObject now, gdk_pixbuf_ref() and
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gdk_pixbuf_unref() are deprecated in favour of g_object_ref()
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and g_object_unref () resp.
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</para>
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</note>
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<para>
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<emphasis>Finalizing</emphasis> a pixbuf means to free its pixel
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data and to free the #GdkPixbuf structure itself. Most of the
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library functions that create #GdkPixbuf structures create the
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pixel data by themselves and define the way it should be freed;
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you do not need to worry about those. The only function that lets
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you specify how to free the pixel data is
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gdk_pixbuf_new_from_data(). Since you pass it a pre-allocated
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pixel buffer, you must also specify a way to free that data. This
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is done with a function of type #GdkPixbufDestroyNotify. When a
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pixbuf created with gdk_pixbuf_new_from_data() is finalized, your
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destroy notification function will be called, and it is its
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responsibility to free the pixel array.
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</para>
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<para>
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As an extension to traditional reference counting, #GdkPixbuf
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structures support defining a handler for the last unref
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operation. If g_object_unref() is called on a #GdkPixbuf
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structure that has a reference count of 1, i.e. its last
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reference, then the pixbuf's last unref handler function will be
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called. It is up to this function to determine whether to
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finalize the pixbuf using gdk_pixbuf_finalize() or to just
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continue execution. This can be used to implement a pixbuf cache
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efficiently; please see the programmer's documentation for
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details.
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</para>
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<!-- FIXME: link the last sentence above to the relevant section of
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the programmer's docs.
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-->
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<!-- ##### SECTION See_Also ##### -->
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<para>
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#GdkPixbuf, gdk_pixbuf_new_from_data().
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</para>
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<!-- ##### USER_FUNCTION GdkPixbufDestroyNotify ##### -->
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<para>
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A function of this type is responsible for freeing the pixel array
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of a pixbuf. The gdk_pixbuf_new_from_data() function lets you
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pass in a pre-allocated pixel array so that a pixbuf can be
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created from it; in this case you will need to pass in a function
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of #GdkPixbufDestroyNotify so that the pixel data can be freed
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when the pixbuf is finalized.
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</para>
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@pixels: The pixel array of the pixbuf that is being finalized.
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@data: User closure data.
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<!-- ##### FUNCTION gdk_pixbuf_ref ##### -->
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<para>
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</para>
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@pixbuf:
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@Returns:
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<!-- ##### FUNCTION gdk_pixbuf_unref ##### -->
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<para>
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</para>
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@pixbuf:
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