File: BitMap3d.mesa
Last edited by Bier on July 30, 1984 1:29:29 am PDT
Copyright © 1984 by Xerox Corporation. All rights reserved.
Created June 14, 1982 4:21 pm
Contents: calls to GraphicsExtra.mesa to double buffer graphics.
DIRECTORY
Graphics,
GraphicsOps,
ViewerClasses;
BitMap3d: DEFINITIONS =
BEGIN
We draw into the unseen bitmap and then draw that map onto our screen when we want to see the picture.
BitmapRef: TYPE = REF READONLY BitmapRep;
BitmapRep: TYPE = GraphicsOps.BitmapRep;
AlternateDisplayContext: TYPE = REF AlternateDisplayContextObj;
AlternateDisplayContextObj:
TYPE =
RECORD [
dc: Graphics.Context,
bitMap: BitmapRef];
Viewer: TYPE = ViewerClasses.Viewer;
DrawAltDisplayContext: PROC [dc: Graphics.Context, altDC: AlternateDisplayContext];
GetAltDisplayContext: PROC RETURNS [altDC: AlternateDisplayContext];
ResizeBitMap: PROC [viewer: Viewer, altDC: AlternateDisplayContext]; -- must resize each time viewer changes size.
Erase: PROC [altDC: AlternateDisplayContext];
END.