@pixbuf:
@Returns:
If this argument is %TRUE, then the width of the pixbuf will be
considered to be in pixels, that is, it will not be visually
scaled even if the item's affine transformation changes. If this
is %FALSE, then the width of the pixbuf will be considered to be
in canvas units, and so will be scaled normally by affine
transformations. The default is %FALSE.
GdkRGB
@image_module:
@error:
@Returns:
#GnomeCanvas, #GdkPixbuf
@GDK_PIXBUF_ERROR_CORRUPT_IMAGE:
@GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY:
@GDK_PIXBUF_ERROR_BAD_OPTION_VALUE:
@GDK_PIXBUF_ERROR_UNKNOWN_TYPE:
@GDK_PIXBUF_ERROR_UNSUPPORTED_OPERATION:
@GDK_PIXBUF_ERROR_FAILED:
Canvas item to display #GdkPixbuf images.
The &gdk-pixbuf; Xlib library provides several convenience
functions to render pixbufs to X drawables. It uses XlibRGB to
render the image data.
These functions are analogous to those for the Gdk version of
&gdk-pixbuf;.
@pixbuf:
@bitmap:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_threshold:
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.
&gdk-pixbuf; Xlib initialization
@src:
@dest:
@saturation:
@pixelate:
@pixbuf:
@Returns:
@pixbuf:
@Returns:
Works in the same way as the width_in_pixels
argument. The default is %FALSE.
@animation:
@Returns:
@animation:
@Returns:
Rendering
Getting parts of an X drawable's image data into a pixbuf.
@module_name:
@format_check:
@module:
@load:
@load_xpm_data:
@begin_load:
@stop_load:
@load_increment:
@load_animation:
@save:
@pixbuf:
@Returns:
@animation:
@Returns:
Getting parts of a drawable's image data into a pixbuf.
@pixbuf:
@pixmap_return:
@mask_return:
@alpha_threshold:
@src:
@dest:
@dest_x:
@dest_y:
@dest_width:
@dest_height:
@offset_x:
@offset_y:
@scale_x:
@scale_y:
@interp_type:
@overall_alpha:
@check_x:
@check_y:
@check_size:
@color1:
@color2:
@data:
@colorspace:
@has_alpha:
@bits_per_sample:
@width:
@height:
@rowstride:
@destroy_fn:
@destroy_fn_data:
@Returns:
@filename:
@error:
@Returns:
Works in the same way as the x_in_pixels
argument, but controls whether the y translation offset is
scaled or not. The default is %FALSE.
This structure describes an animation, which is represented as a
list of #GdkPixbufFrame structures.
Initializing the &gdk-pixbuf; Xlib library.
@frame:
@Returns:
This enumeration describes the different interpolation modes that
can be used with the scaling functions.
Cubic filtering is missing from the list; hyperbolic
interpolation is just as fast and results in higher quality.
@GDK_INTERP_NEAREST: Nearest neighbor sampling; this is the fastest
and lowest quality mode.
@GDK_INTERP_TILES: This is an accurate simulation of the PostScript
image operator without any interpolation enabled. Each pixel is
rendered as a tiny parallelogram of solid color, the edges of which
are implemented with antialiasing. It resembles nearest neighbor for
enlargement, and bilinear for reduction.
@GDK_INTERP_BILINEAR: Bilinear interpolation. For enlargement, it is
equivalent to point-sampling the ideal bilinear-interpolated image.
For reduction, it is equivalent to laying down small tiles and
integrating over the coverage area.
@GDK_INTERP_HYPER: This is the slowest and highest quality
reconstruction function. It is derived from the hyperbolic filters in
Wolberg's "Digital Image Warping", and is formally defined as the
hyperbolic-filter sampling the ideal hyperbolic-filter interpolated
image (the filter is designed to be idempotent for 1:1 pixel mapping).
@pixbuf:
@drawable:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@alpha_mode:
@alpha_threshold:
@dither:
@x_dither:
@y_dither:
Each animation frame can have several things happen to it when the
next frame is displayed. The #GdkPixbufFrameAction determines
this. These are essentially the overlay modes supported by GIF
animations.
@GDK_PIXBUF_FRAME_RETAIN: The previous image should remain displayed,
and will potentially be occluded by the new frame.
@GDK_PIXBUF_FRAME_DISPOSE: The animation will be reverted to the state
before the frame was shown.
@GDK_PIXBUF_FRAME_REVERT: The animation will be reverted to the first
frame.
The XlibRGB set of functions is a port of the GdkRGB library to
use plain Xlib and X drawables. You can use these functions to
render RGB buffers into drawables very quickly with high-quality
dithering.
This canvas item displays #GdkPixbuf images. It handles full
affine transformations in both GDK and antialiased modes, and also
supports the W3C's SVG-like scaling and
translation semantics for absolute pixel values.
#GdkPixbuf structures may be shared among different pixbuf canvas
items; the pixbuf item uses #GdkPixbuf's reference counting
functions for this.
Custom Scaling and Translation
In addition to the normal affine transformations supported by
canvas items, the #GnomeCanvasPixbuf item supports independent
object arguments for scaling and translation. This is useful
for explicitly setting a size to which the pixbuf's image will
be scaled, and for specifying translation offsets that take
place in the item's local coordinate system.
By default, the pixbuf canvas item will attain the size in units
of the #GdkPixbuf it contains. If a #GnomeCanvasPixbuf is
configured to use a #GdkPixbuf that has a size of 300 by 200
pixels, then the pixbuf item will automatically obtain a size of
300 by 200 units in the item's local coordinate system. If the
item is transformed with a scaling transformation of (0.5, 2.0),
then the final image size will be of 150 by 400 pixels.
To set custom width and height values, you must set the width_set or height_set
arguments to %TRUE, and then set the width or height arguments to
the desired values. The former two arguments control whether
the latter two are used when computing the final image's size;
they are both %FALSE by default so that the pixbuf item will
attain a size in units equal to the size in pixels of the
#GdkPixbuf that the item contains.
The custom translation offsets are controlled by the x and y arguments. The logical
upper-left vertex of the image will be translated by the
specified distance, aligned with the item's local coordinate
system.
Absolute Pixel Scaling and Translation
The Scalable Vector
Graphics specification (SVG) of the World Wide Web Consortium also
allows images to be translated and scaled by absolute pixel
values that are independent of an item's normal affine
transformation.
Normally, the pixbuf item's translation and scaling arguments
are interpreted in units, so they will be modified by the item's
affine transformation. The width_in_pixels,
height_in_pixels,
x_in_pixels, and
y_in_pixels
object arguments can be used to modify this behavior. If one of
these arguments is %TRUE, then the corresponding scaling or
translation value will not be affected lengthwise by the pixbuf
item's affine transformation.
For example, consider a pixbuf item whose size is (300, 200).
If the item is modified with a scaling transformation of (0.5,
2.0) but the width_in_pixels
is set to %TRUE, then the item will appear to be (300, 400)
pixels in size. This means that in this case the item's affine
transformation only applies to the height value, while the width
value is kept in absolute pixels.
Likewise, consider a pixbuf item whose (x, y) arguments are set to
(30, 40). If the item is then modified by the same scaling
transformation of (0.5, 2.0) but the y_in_pixels
argument is set to %TRUE, then the image's upper-left corner
will appear to be at position (15, 40). In this case, the
affine transformation is applied only to the x offset, while the
y offset is kept in absolute pixels.
In short, these arguments control whether a particular dimension
of a pixbuf item is scaled or not in the normal way by the
item's affine transformation.
Resource Management
When you set the #GdkPixbuf structure that a #GnomeCanvasPixbuf
item will use by setting the pixbuf argument, a
reference count will be added to that #GdkPixbuf structure.
When the pixbuf item no longer needs the #GdkPixbuf structure,
such as when the item is destroyed or when a new pixbuf
structure is passed to it, then the old #GdkPixbuf structure
will be automatically unreferenced.
This means that if an application just needs to load a pixbuf
image and set it into a pixbuf canvas item, it can do the
following to ‘forget’ about the pixbuf structure:
GdkPixbuf *pixbuf;
GnomeCanvasItem *item;
pixbuf = gdk_pixbuf_new_from_file ("foo.png");
g_assert (pixbuf != NULL);
item = gnome_canvas_item_new (gnome_canvas_root (my_canvas),
gnome_canvas_pixbuf_get_type (),
"pixbuf", pixbuf,
NULL);
gdk_pixbuf_unref (pixbuf);
After this happens, the reference count of the pixbuf structure
will be 1: the gdk_pixbuf_new_from_file() function creates it
with a reference count of 1, then setting the pixbuf argument of
the #GnomeCanvasPixbuf item increases it to 2, and then it is
decremented to 1 by the call to gdk_pixbuf_unref(). When the
canvas item is destroyed, it will automatically unreference the
pixbuf structure again, causing its reference count to drop to
zero and thus be freed.
Rendering a pixbuf to a GDK drawable.
Casts a #GtkObject to a #GdkPixbufLoader.
@obj: A GTK+ object.
Determines whether the x argument is used to
translate the pixbuf from its logical origin in item-relative
coordinates.
@pixbuf:
@user_data:
Casts a #GtkOjbect to a #GnomeCanvasPixbuf.
@obj: A GTK+ object.
@pixbuf:
@Returns:
@pixbuf:
@Returns:
This enumeration defines the color spaces that are supported by
the &gdk-pixbuf; library. Currently only RGB is supported.
@GDK_COLORSPACE_RGB: Indicates a red/green/blue additive color space.
Determines whether the width argument is taken
into account when scaling the pixbuf item. If this argument is
%FALSE, then the width value of the pixbuf will be used instead.
This argument is %FALSE by default.
@buffer:
@size:
@filename:
@error:
@Returns:
The functions in this section allow you to take the image data
from an X 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.
These functions are analogous to those for the Gdk version of
&gdk-pixbuf;.
@name:
@error:
@Returns:
@colorspace:
@has_alpha:
@bits_per_sample:
@width:
@height:
@Returns:
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.
@inline_pixbuf:
@copy_pixels:
@length:
@error:
@Returns:
XlibRGB
@pixbuf:
@pixbuf:
@Returns:
A function of this type is responsible for freeing the pixel array
of a pixbuf. The gdk_pixbuf_new_from_data() function lets you
pass in a pre-allocated pixel array so that a pixbuf can be
created from it; in this case you will need to pass in a function
of #GdkPixbufDestroyNotify so that the pixel data can be freed
when the pixbuf is finalized.
@pixels: The pixel array of the pixbuf that is being finalized.
@data: User closure data.
@data:
@Returns:
@art_pixbuf:
@Returns:
@src:
@dest_width:
@dest_height:
@interp_type:
@Returns:
Indicates the height the pixbuf will be scaled to. This argument
will only be used if the height_set argument
is %TRUE. Works in the same way as the width argument.
@src:
@dest:
@dest_x:
@dest_y:
@dest_width:
@dest_height:
@offset_x:
@offset_y:
@scale_x:
@scale_y:
@interp_type:
@overall_alpha:
@frame:
@Returns:
@pixbuf:
@Returns:
Xlib Rendering
gdk_image_get().
Contains a pointer to a #GdkPixbuf structure that will be used by
the pixbuf canvas item as an image source. When a pixbuf is set
its reference count is incremented; if the pixbuf item kept a
pointer to another #GdkPixbuf structure, the reference count of
this structure will be decremented. Also, the GdkPixbuf's
reference count will automatically be decremented when the
#GnomeCanvasPixbuf item is destroyed. When a pixbuf is queried, a
reference count will not be added to the return value; you must do
this yourself if you intend to keep the pixbuf structure around.
@frame:
@Returns:
@frame:
@Returns:
Functions for rendering RGB buffers to X drawables.
Indicates the horizontal translation offset of the pixbuf item's
image. This offset may not actually appear horizontal, since it
will be affected by the item's affine transformation. The default
is 0.0.
Indicates the vertical translation offset of the pixbuf item's
image. Works in the same way as the x argument. The default is
0.0.
@animation:
@Returns:
Indicates the width the pixbuf will be scaled to. This argument
will only be used if the width_set argument
is %TRUE. If the width_in_pixels
argument is %FALSE, the width will be taken to be in canvas units,
and thus will be scaled along with the canvas item's affine
transformation. If width_in_pixels is %TRUE, the width will be
taken to be in pixels, and will visually remain a constant size
even if the item's affine transformation changes.
@src:
@dest_width:
@dest_height:
@interp_type:
@overall_alpha:
@check_size:
@color1:
@color2:
@Returns:
@app:
@modinfo:
@pixbuf:
@last_unref_fn:
@last_unref_fn_data:
Determines whether the height argument is
taken into account when scaling the pixbuf item. Works in the
same way as the width_set argument.
The default is %FALSE.
@animation:
@pixbuf:
@drawable:
@gc:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@dither:
@x_dither:
@y_dither:
In addition to the normal Gdk-specific functions, the &gdk-pixbuf;
package provides a small library that lets Xlib-only applications
use #GdkPixbuf structures and render them to X drawables. The
functions in this section are used to initialize the &gdk-pixbuf;
Xlib library. This library must be initialized near the beginning
or the program or before calling any of the other &gdk-pixbuf;
Xlib functions; it cannot be initialized automatically since
Xlib-only applications do not call gdk_rgb_init() like GNOME
applications do.
@frame:
@Returns:
GdkRGB
Rendering a pixbuf to an X drawable.
@pixbuf:
@x:
@y:
@width:
@height:
@user_data:
@pixbuf:
@pixbuf:
@Returns:
@dest:
@src:
@cmap:
@src_x:
@src_y:
@dest_x:
@dest_y:
@width:
@height:
@Returns:
@frame:
@user_data:
@app:
@modinfo:
gdk-pixbuf-io
@pixbuf:
@Returns:
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.
@animation:
@Returns:
GnomeCanvasPixbuf
This is the main structure in the &gdk-pixbuf; library. It is
used to represent images. It contains information about the
image's pixel data, its color space, bits per sample, width and
height, and the rowstride or number of bytes between rows.
@src:
@dest:
@dest_x:
@dest_y:
@dest_width:
@dest_height:
@offset_x:
@offset_y:
@scale_x:
@scale_y:
@interp_type:
@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.
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.
This structure describes a frame in a #GdkPixbufAnimation. Each
frame consists of a #GdkPixbuf, an offset of the frame within the
animation's bounding box, a duration, and an overlay mode or
action.
@pixbuf:
@substitute_color:
@r:
@g:
@b:
@Returns:
@pixbuf:
@user_data:
@src_pixbuf:
@src_x:
@src_y:
@width:
@height:
@dest_pixbuf:
@dest_x:
@dest_y:
X Drawables to Pixbufs
Drawables to Pixbufs
If this argument is %TRUE, the pixbuf's translation with respect
to its logical origin in item-relative coordinates will be in
pixels, that is, the visible offset will not change even if the
item's affine transformation changes. If it is %FALSE, the
pixbuf's translation will be taken to be in canvas units, and thus
will change along with the item's affine transformation. The
default is %FALSE.
XlibRGB
@filename:
@error:
@Returns: