gtk/docs/reference/gdk-pixbuf/tmpl/rendering.sgml
Federico Mena Quintero 37ac7d593e Your eyes are bloodshot.
Your eyes are bloodshot.

Your mouth starts to foam.

Your hands are shaking.

You know your need your fix.

NEED MORE ABSTRACTION!

2000-04-12  Federico Mena Quintero  <federico@helixcode.com>

	This comes from an excellent idea by Tim Janik (timj@gtk.org) to
	hook to the last unref operation.

	* gdk-pixbuf/gdk-pixbuf.c (gdk_pixbuf_set_last_unref_handler): New
	function to set the last unref handler for a pixbuf.
	(gdk_pixbuf_finalize): New function to actually finalize a pixbuf.
	It calls the pixbuf's destroy notification function and frees the
	GdkPixbuf structure itself.
	(gdk_pixbuf_unref): Use the last unref function of the pixbuf if
	available.

	* gdk-pixbuf/gdk-pixbuf-private.h (struct _GdkPixbuf): New fields
	for the last unref handler and its user data.

	* gdk-pixbuf/gdk-pixbuf-data.c (gdk_pixbuf_new_from_data): Use
	g_new0() to allocate the pixbuf.

	* gdk-pixbuf/gdk-pixbuf-loader.c (gdk_pixbuf_loader_class_init):
	Fixed the call to gtk_signal_new() for the "frame_done" signal; it
	was not specifying the `frame' argument.

	* gdk-pixbuf/gdk-pixbuf-animation.c
	(gdk_pixbuf_animation_get_width): Fixed docstring.
	(gdk_pixbuf_animation_get_height): Likewise.
	(gdk_pixbuf_animation_get_num_frames): Likewise.
	(gdk_pixbuf_animation_get_frames): Likewise.

	* doc/gdk-pixbuf-sections.txt: Updated with the new functions and
	types.

	* doc/tmpl/gdk-pixbuf.sgml: Added the description for GdkColorspace.

	* doc/tmpl/scaling.sgml: Added the description for GdkInterpType.

	* doc/tmpl/refcounting.sgml: Updated with the information about
	the last unref handler.

	* doc/tmpl/*.sgml: Markup tweaks.

	* gdk-pixbuf/Makefile.am (libgnomecanvaspixbuf_la_LDFLAGS): Sigh,
	update the libtool version number for libgnomecanvaspixbuf as
	well.
	(libpixbufloader_*_la_LDFLAGS): The loaders need to be versioned
	as well, or the old ones won't work with the new stuff.  Also,
	renamed the modules as follows.

	* gdk-pixbuf/gdk-pixbuf-io.c (gdk_pixbuf_load_module): Now the
	modules are called "libpixbufloader-<format>.so" instead of
	"libpixbuf-<format>.so".  They needed renaming so that the new
	loaders won't overwrite the old ones; even with the versioning
	stuff, the new .so symlink to the .so.1.0.0 would overwrite the
	old real .so file.
2000-04-13 01:18:41 +00:00

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<!-- ##### SECTION Title ##### -->
Rendering
<!-- ##### SECTION Short_Description ##### -->
Rendering a pixbuf to a GDK drawable.
<!-- ##### SECTION Long_Description ##### -->
<para>
The <application>gdk-pixbuf</application> library provides several
convenience functions to render pixbufs to GDK drawables. It uses
the GdkRGB to render the image data.
</para>
<para>
At this point there is not a standard alpha channel extension for
the X Window System, so it is not possible to use full opacity
information when painting images to arbitrary drawables. The
<application>gdk-pixbuf</application> convenience functions will
threshold the opacity information to create a bi-level clipping
mask (black and white), and use that to draw the image onto a
drawable.
</para>
<important>
<para>
Since these functions use GdkRGB for rendering, you must
initialize GdkRGB before using any of them. You can do this by
calling gdk_rgb_init() near the beginning of your program.
</para>
</important>
<!-- ##### SECTION See_Also ##### -->
<para>
GdkRGB
</para>
<!-- ##### ENUM GdkPixbufAlphaMode ##### -->
<para>
These values can be passed to
gdk_pixbuf_render_to_drawable_alpha() to control how the alpha
chanel of an image should be handled. This function can create a
bilevel clipping mask (black and white) and use it while painting
the image. In the future, when the X Window System gets an alpha
channel extension, it will be possible to do full alpha
compositing onto arbitrary drawables. For now both cases fall
back to a bilevel clipping mask.
</para>
@GDK_PIXBUF_ALPHA_BILEVEL: A bilevel clipping mask (black and white)
will be created and used to draw the image. Pixels below 0.5 opacity
will be considered fully transparent, and all others will be
considered fully opaque.
@GDK_PIXBUF_ALPHA_FULL: For now falls back to #GDK_PIXBUF_ALPHA_BILEVEL.
In the future it will do full alpha compositing.
<!-- ##### FUNCTION gdk_pixbuf_render_to_drawable_alpha ##### -->
<para>
</para>
@pixbuf:
@drawable:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_mode:
@alpha_threshold:
@dither:
@x_dither:
@y_dither:
<!-- ##### FUNCTION gdk_pixbuf_render_to_drawable ##### -->
<para>
</para>
@pixbuf:
@drawable:
@gc:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@dither:
@x_dither:
@y_dither:
<!-- ##### FUNCTION gdk_pixbuf_render_threshold_alpha ##### -->
<para>
</para>
@pixbuf:
@bitmap:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_threshold:
<!-- ##### FUNCTION gdk_pixbuf_render_pixmap_and_mask ##### -->
<para>
</para>
@pixbuf:
@pixmap_return:
@mask_return:
@alpha_threshold:
<!--
Local variables:
mode: sgml
sgml-parent-document: ("../gdk-pixbuf.sgml" "book" "refsect2" "")
End:
-->