blast old implementation notes, #66

doc/implementation-notes.md

@@ -1,34 +1,2 @@
-
-:GENERAL:
-
-- Shelf, Scale & Number Line all use a add/remove/clear/populate mechanism for managing movable items. User draggable
-items are managed at the top-most model level (i.e. URShoppingModel & RacingLabModel)
-
-- Positioning & tween animation for all movable nodes is done in the common/model/Movable base class
-
-- The touch area for all movable objects is currently the bounds of the image being used. This is problematic when
-trying to adjust the touch area. Right now you have to resize the image (see Racing Lab checkered_flag.png).
-There's got to be a better way to handle this.
-
-- When profiling memory usage, if asserts are enabled the sim will leak memory because of the
-SUN/buttons/RectangularPushButton's being used. Apparently SUN buttons dispose fails when assertions are enabled,
-so the disposes are turned off if asserts are turned on (see sun/#212)
-
-- FuzzMouse memory testing seems to stabilize around 30Mb, though I have a sneaking suspicion a few
-URNumberLineMarkers are still not getting disposed of properly.
-
-:SHOPPING & SHOPPING LAB:
-
-- Most functionality is in common as the Shopping & Shopping Lab screens are very similar.
-
-- The main models (Shelf, Scale & Number Line) are all derived from ItemCollection, which holds multiple arrays of items
-(i.e. apples, carrots, etc.. ). Instances of individual items are moved from one model to another when a user drags them.
-(e.g. from shelf to scale or vice versa). The item arrays are switched in each model when the itemTypeProperty changes.
-
-- Any item that is not dragged to the scale drop zone is automatically moved back to the shelf. This is initiated in
-common/shopping/model/URShoppingModel
-
-:RACING LAB:
-
-TODO
+TODO see https://github.com/phetsims/unit-rates/issues/66