gtk:drag-check-threshold (widget xstart ystart xcurrent ycurrent)

source -- a gtk:drag-source object
xstart -- an integer for the x coordinate of start of drag
ystart -- an integer for the y coordinate of start of drag
xcurrent -- an integer for the current x coordinate
ycurrent -- an integer for the current y coordinate

True if the drag threshold has been passed.

Checks to see if a mouse drag starting at (xstart, ystart) and ending at (xcurrent, ycurrent) has passed the GTK drag threshold, and thus should trigger the beginning of a drag-and-drop operation.