class _height_dragger(DelegatingInstanceOrExpr):
# args
#e coordsystem? for now let x/y be the way it spreads, z be the height
height_ref = Arg(StateRef, doc="stateref to a height variable")
# appearance/behavior
#e should draw some "walls" too, and maybe limit the height
# note: the following sets up a cyclic inter-Instance ref ( drag_handler -> delegate -> drag_handler);
# it works since the actual refs are symbolic (getattr_Expr(_self, 'attr'), not evalled except when used).
drag_handler = Instance(
xxx_drag_behavior(_self._delegate, height_ref,
Ray(ORIGIN, DX))) ### DX for initial test, then DZ
# note: passing _self._delegate (not _self.delegate) fixed my "undiagnosed bug".
delegate = DraggableObject(
Image(
"blueflake.png"
), ###e needs an option to be visible from both sides (default True, probably)
## constrain_delta = _self.constrain_delta, ###IMPLEM constrain_delta in DraggableObject
## delta_stateref = height_ref ###IMPLEM delta_stateref [done] (and rename it); and change this to make height_ref a number not vector;
##e and maybe include the constraint in that transform, since it seems implicit in it anyway. ####HOW in semantics?
# ... = PropertyRef(DZ * height_ref.value, Set( height_ref.value, project_onto_unit_vector( _something, DZ ))
# ... = TransformStateRef( height_ref, ... ) # funcs? or formula in terms of 1 or 2 vars? with a chance at solving it?? ##e
_kluge_drag_handler=drag_handler)
## def constrain_delta(self, delta):
## not yet - called
## return project_onto_unit_vector( delta, DZ)
pass
def current_event_mouseray(self):
p0 = self.highlightable.current_event_mousepoint(
depth=0.0) # nearest depth ###k
p1 = self.highlightable.current_event_mousepoint(
depth=1.0) # farthest depth ###k
return Ray(
p0, p1 - p0
) #e passing just p1 should be ok too, but both forms can't work unless p0,p1 are typed objects...
class xxx_drag_behavior(
DragBehavior
): # revised 070316; on 070318 removed comments that were copied into version _3
"""a drag behavior which moves the original hitpoint along a line,
storing only its 1d-position-offset along the line's direction
[noting that the hitpoint is not necessarily equal to the moved object's origin]
[#doc better]
"""
# args
highlightable = Arg(
DraggableObject
) # kluge; revised 070316, delegate -> highlightable [works no worse than before [same bug as before]]
# [but it's misnamed -- it has to be a DraggableObject since we modify its .motion]
###e rename, but what is it for?
posn_parameter_ref = Arg(StateRef,
doc="where the variable height is stored")
###e rename
constrain_to_line = Arg(
Ray,
Ray(ORIGIN, DY),
doc="the line/ray on which the height is interpreted as a position")
###e rename: constraint_line? line_to_constrain_to? constrain_to_this_line?
# dflt_expr is just for testing #e remove it
def current_event_mouseray(self):
p0 = self.highlightable.current_event_mousepoint(
depth=0.0) # nearest depth ###k
p1 = self.highlightable.current_event_mousepoint(
depth=1.0) # farthest depth ###k
return Ray(
p0, p1 - p0
) #e passing just p1 should be ok too, but both forms can't work unless p0,p1 are typed objects...
def on_press(self):
self.startpoint = self.highlightable.current_event_mousepoint(
) # the touched point on the visible object (hitpoint)
self.offset = self.startpoint - (
ORIGIN + self.highlightable.motion
) #k maybe ok for now, but check whether sensible in long run
self.line = self.constrain_to_line + self.offset # the line the hitpoint is on (assuming self.motion already obeyed the constraint)
def on_drag(self):
# Note: we can assume this is a "real drag" (not one which is too short to count), due to how we are called.
mouseray = self.current_event_mouseray()
## self._cmd_drag_from_to( oldpoint, point) # use Draggable interface cmd on self
# ie self.delta_stateref.value = self.delta_stateref.value + (p2 - p1)
## def drag_mouseray_from_to(self, oldray, newray): # sort of like _cmd_from_to (sp?) in other eg code
## "[part of an interface XXX related to drag behaviors]"
k = self.line.closest_pt_params_to_ray(mouseray)
if k is not None:
# store k
self.posn_parameter_ref.value = k ####e by analogy with DraggableObject, should we perhaps save this side effect until the end?
# compute new posn from k
self.highlightable.motion = self.constrain_to_line.posn_from_params(
k) #e review renaming, since we are asking it for a 3-tuple
####### LOGIC BUG: what causes self.motion to initially come from this formula, not from our own state?
# maybe don't use DraggableObject at all? [or as initial kluge, just let initial motion and initial height both be 0]
return
def on_release(self):
pass
pass # end of class xxx_drag_behavior
def current_event_mouseray(self):
p0 = self.current_event_mousepoint(depth = 0.0) # nearest depth ###k
p1 = self.current_event_mousepoint(depth = 1.0) # farthest depth ###k
return Ray(p0, p1 - p0)