A function of this type can be used to override the default
operation when a pixbuf loses its last reference, i.e. when
gdk_pixbuf_unref() is called on a #GdkPixbuf structure that has a
reference count of 1. This function should determine whether to
finalize the pixbuf by calling gdk_pixbuf_finalize(), or whether
to just resume normal execution. The last unref handler for a
#GdkPixbuf can be set using the
gdk_pixbuf_set_last_unref_handler() function. By default, pixbufs
will be finalized automatically if no last unref handler has been
defined.
@pixbuf: The pixbuf that is losing its last reference.
@data: User closure data.
Drawables to Pixbufs
GdkRGB
@pixbuf:
@pixmap_return:
@mask_return:
@alpha_threshold:
@pixbuf:
@drawable:
@gc:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@dither:
@x_dither:
@y_dither:
@dest:
@src:
@cmap:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@Returns:
@art_pixbuf:
@Returns:
The functions in this section allow you to take the image data
from a GDK drawable and dump it into a #GdkPixbuf. This can be
used for screenshots and other special effects. Note that these
operations can be expensive, since the image data has to be
transferred from the X server to the client program and converted.
@pixbuf:
Rendering a pixbuf to a GDK drawable.
@pixbuf:
@last_unref_fn:
@last_unref_fn_data:
Determines whether the x argument is used to
translate the pixbuf from its logical origin in item-relative
coordinates.
@pixbuf:
@Returns:
@pixbuf:
@drawable:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_mode:
@alpha_threshold:
@dither:
@x_dither:
@y_dither:
gdk_image_get().
Rendering
Casts a #GtkObject to a #GdkPixbufLoader.
@obj: A GTK+ object.
Determines whether the y argument is used to
translate the pixbuf from its logical origin in item-relative
coordinates. Works in the same way as the x_set argument. The
default is %FALSE.
The gdk-pixbuf library provides several
convenience functions to render pixbufs to GDK drawables. It uses
the GdkRGB to render the image data.
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
gdk-pixbuf 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.
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.
Getting parts of a drawable's image data into a pixbuf.
@pixbuf:
@bitmap:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_threshold:
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.
@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.
gdk-pixbuf-io