GtkPreview::size
void size(int width, int height);
Sets the dimensions of the preview to width pixels
wide by height pixels high.
size() only sets the requested
size. The actual size of the preview image depends on the size and
settings of the container that encloses the widget. If the preview is
allowed to expand to fill the container, it may appear larger than the
dimensions requested with the size() method.
See also: set_expand()
