This patch adds drag functionality to {nav View} mode. A
drag operation is only initiated if dragging wouldn't
otherwise do something, e.g. when zoomed and the image is
pannable, or the crop tool is active.
In order to get a drag pixmap for all cases (videos
included), we use KIOa ThumbnailProvider to generate a file
preview. However, if the image is modified, we generate a
if the image is modified,new pixmap using the edited version. we generate a new pixmap uUsing
the edited version.`MimeTypeUtils::selectionMimeData`, Using `MimeTypeUtils::selectionMimeData`,this should mean the
this should mean the drag pixmap always matches the image the receiving
the receiving application gets.
BUG: 386034
FIXED-IN: 18.08.0
{F5781358}