<<>>
    <<TreeGrapher.mesa>>
        <<Copyright Ó 1990, 1991 by Xerox Corporation.  All rights reserved.>>
        <<Michael Plass, July 13, 1990 4:37 pm PDT>>
        <<>>
    DIRECTORY
        ImagerBox USING [Box],
        Vector2 USING [VEC];

    TreeGrapher: CEDAR DEFINITIONS
    ~ BEGIN OPEN ImagerBox, Vector2;

        Node: TYPE = REF NodeRep;
        NodeRep: TYPE = RECORD [
            data: REF,
            class: REF ClassRep,
            children: LIST OF Node,
            layout: REF LayoutRep ¬ NIL
            ];

        Direction: TYPE = { N, E, S, W }; -- compass directions

        ClassRep: TYPE = RECORD [
            classData: REF,
            bounds: PROC [self: Node] RETURNS [Box],
            attachmentPoint: PROC [self: Node, direction: Direction] RETURNS [VEC]
            ];

        LayoutRep: TYPE = RECORD [
            origin: VEC,
            bounds: Box, -- cached value returned by self.class.bounds[self]
            treeBox: Box -- Absolute, once processing is complete
            ];

        LayoutParameters: TYPE = REF LayoutParametersRep;
        LayoutParametersRep: TYPE = RECORD [
            descendantPad: REAL ¬ 10.0,
            descendantDirection: Direction ¬ $E,
            siblingPad: REAL ¬ 6.0,
            siblingDirection: Direction ¬ $N,
            ext: REF
            ];

        DoLayout: PROC [root: Node, lp: LayoutParameters];

        Resolve: PROC [root: Node, p: VEC] RETURNS [Node];

        DefaultAttachmentPoint: PROC [self: Node, direction: Direction] RETURNS [VEC];


    END.