GdkDrawable and converts it to an RGB(A)
representation inside a GdkPixbuf. In other words, copies
image data from a server-side drawable to a client-side RGB(A) buffer.
This allows you to efficiently read individual pixels on the client side.gdkPixbufGetFromDrawable(dest = NULL, src, cmap = NULL, src.x, src.y, dest.x, dest.y, width, height)destNULL if a new pixbuf should be created. [ allow-none ]srccmapsrc doesn't have one set.src.xsrc.ydest.xdest is NULL.dest.ydest is NULL.widthheightGdkPixbuf] The same pixbuf as dest if it was non-NULL, or a newly-created
pixbuf with a reference count of 1 if no destination pixbuf was specified, or NULL on errorsrc has no colormap (gdkDrawableGetColormap
returns NULL), then a suitable colormap must be specified.
Typically a GdkWindow or a pixmap created by passing a GdkWindow
to gdkPixmapNew will already have a colormap associated with
it. If the drawable has a colormap, the cmap argument will be
ignored. If the drawable is a bitmap (1 bit per pixel pixmap),
then a colormap is not required; pixels with a value of 1 are
assumed to be white, and pixels with a value of 0 are assumed to be
black. For taking screenshots, gdkColormapGetSystem returns
the correct colormap to use.
If the specified destination pixbuf dest is NULL, then this
function will create an RGB pixbuf with 8 bits per channel and no
alpha, with the same size specified by the width and height
arguments. In this case, the dest.x and dest.y arguments must be
specified as 0. If the specified destination pixbuf is not NULL
and it contains alpha information, then the filled pixels will be
set to full opacity (alpha = 255).
If the specified drawable is a pixmap, then the requested source
rectangle must be completely contained within the pixmap, otherwise
the function will return NULL. For pixmaps only (not for windows)
passing -1 for width or height is allowed to mean the full width
or height of the pixmap.
If the specified drawable is a window, and the window is off the
screen, then there is no image data in the obscured/offscreen
regions to be placed in the pixbuf. The contents of portions of the
pixbuf corresponding to the offscreen region are undefined.
If the window you're obtaining data from is partially obscured by
other windows, then the contents of the pixbuf areas corresponding
to the obscured regions are undefined.
If the target drawable is not mapped (typically because it's
iconified/minimized or not on the current workspace), then NULL
will be returned.
If memory can't be allocated for the return value, NULL will be returned
instead.
(In short, there are several ways this function can fail, and if it fails
it returns NULL; so check the return value.)
This function calls gdkDrawableGetImage internally and
converts the resulting image to a GdkPixbuf, so the
documentation for gdkDrawableGetImage may also be relevant.