Proposed: Slider label positioning offset methods

    /minoffset % - => x y
	at left end of hslider, at bottom of vslider
    /maxoffset % - => x y
	at right end of hslider, at top of vslider
    /mintickoffset % - => x y
        at left end below hslider, at top to right of vslider
    /maxtickoffset % - => x y
	at right end below hslider, at bottom to right of vslider

    These methods return the (x,y) offset from the slider's lower left
    corner to the point where a label should be justified. These offsets
    are useful for positioning labels and text fields relative to sliders
    in panels with calculated layout.


Proposed: ClassLayout offset method name backstop

    In a calculated layout specification, if a named offset is not
    defined in the CornerPositions dict (not one of /North /East /West
    /South /NorthWest /SouthWest /NorthEast /SouthEast /Center) then a
    message of that name is sent to the object in question.  The
    offset should be the name of a method returning an (x,y) offset
    from the object's lower left corner. The offset method name will
    work the in both contexts that the corner position names may
    appear in calculated layout specifications.

    Normal calculated layout usage, positioning an object's west edge along
    the previous object's east edge:

	/West {/East PREVIOUS POSITION}

    Positioning a object's hot spot at the center of its parent:

	/hotspotoffset {/Center PARENT POSITION}

    Positioning an object's north edge below a slider's minimum tick mark:

	/North {/minlabeloffset /slider position}

    Positioning an object's left sidebearing at the previous object's right
    sidebearing:

	/leftbearingoffset {/rightbearingoffset PREVIOUS POSITION}


Proposed: ClassLayout /SEND enhancement

    There should be a convenient way to send a message to a named list
    element.

	/SEND { % ...args /method list-element => result...
	    ResolveReference send
	} def


Proposed: ClassLayout /SIZE enhancement

    Combination of the already existing methods: /WIDTH /HEIGHT
    /WIDTH and /HEIGHT can be redefined in terms of /SIZE

	/SIZE { % list-element => width height
	    ResolveReference
	    dup self eq InMinSize? and {
	      pop 0 0
	    } {
	      Size
	    } ifelse
	} def

	/WIDTH { % list-element => width
	  SIZE pop
	} def

	/HEIGHT { % list-element => height
	  SIZE exch pop
	} def

Proposed: ClassBag client names

    There needs to be a way for a client to ask its parent bag for its name.
    There also needs to be a way to ask a bag for the names of its clients.
    These methods I am using in a subclass. They could be merged into
    ClassBag.

	/addclient { % name instance layout => -
	  3 copy pop exch /SetClientName self send
	  /addclient super send
	} def

	/removeclient { % name => client true  |  false
	  /removeclient super send {
	    dup /TNTClientName undef true
	  } { false } ifelse
	} def

	/SetClientName { % client name => -
	  /TNTClientName exch put
	} def

	/ClientName { % client => name
	  /TNTClientName get
	} def

	/clientnames { % - => [ key1 key2 ... ]
	  [ ClientDict { pop } forall ]
	} def

Proposal: Experimental panel souper-upper

    To avoid interobject sends, teach ClassPanel to access the position
    and size of canvas clients by hand.

	/Move { % x y client => -
	    dup type /canvastype eq {
	      movecanvas
	    } {
	      /move exch send
	    } ifelse
	} def

	/Size { % client => width height
	    dup type /canvastype eq {
	      false getbbox 4 2 roll pop pop
	    } {
	      /size exch send
	    } ifelse
	} def

	/Location { % client => x y
	    /location exch send
	} def

	/CellSize { % - => <cell width> <cell height>
	    0 0
	    /regionclientlist self send {
		/size exch send
		4 -1 roll max 3 1 roll max
		pause
	    } forall
	    /children self send {
		false getbbox 4 2 roll pop pop
		4 -1 roll max 3 1 roll max
		pause
	    } forall
	    exch
	} def