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Sun Feb 11 22:16:34 2001 Owen Taylor <otaylor@redhat.com> * */Makefile.am: Use the new snazzy mother-of-all-gtk-doc-makefiles. * gdk/tmpl/* gdk-pixbuf/tmpl/*: Recover a bunch of docs that were lost at one point.
88 lines
3.0 KiB
Plaintext
88 lines
3.0 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 to perform reference counting and memory management on a
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#GdkPixbuf.
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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#GdkPixbuf structures are reference counted. This means that
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an 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. When it no longer needs
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the pixbuf, it should subtract a reference. The pixbuf will be
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destroyed when its reference count drops to zero. Newly-created
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#GdkPixbuf structures start with a reference count of one.
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</para>
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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 gdk_pixbuf_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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