DIRECTORY
GGModelTypes, RefTab;

GGHistoryTypesOpaque: CEDAR DEFINITIONS =
BEGIN

Scene: TYPE = GGModelTypes.Scene;
Slice: TYPE = GGModelTypes.Slice;
SliceParts: TYPE = GGModelTypes.SliceParts;


ChangeType: TYPE = {changingprops, changingstate, capture}; -- to be expanded

Change: TYPE = RECORD [ -- to be expanded
SELECT kind: ChangeType FROM

changingprops => [
op: ATOM, -- an atom, like $SetColor or $SetLineWidth, triggering this entry
slice: Slice, -- the slice being changed
parts: SliceParts, -- the slice parts being changed
oldValue:  REF -- the old value of the changing property
],

changingstate => [
op: ATOM, -- an atom, like $SetScaleUnit
scene: Scene,
oldValue:  REF -- the old value of the changing state variable
],

capture => [
scene: Scene,
virginData: LIST OF Slice, -- hiding place for data needed to undo a capture
virginMap: RefTab.Ref -- key: virginSlice, value: oldSlice.  Used to restore captured data to the original storage occupied when a capture occurs.
],

ENDCASE
];

END.

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GGHistoryTypesOpaque.mesa
Contents:  The Change TYPE.
Copyright Ó 1986, 1988, 1992 by Xerox Corporation.  All rights reserved.
Last edited by Bier on October 31, 1988 4:10:57 pm PST
Bier, October 31, 1988 5:10:06 pm PST

There is one Change record for each subevent.  A subevent is usually a single change on a single operand.
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