DIRECTORYCD, CDVScale;CDVScaleImpl: CEDAR PROGRAMIMPORTS CDVScaleEXPORTS CDVScale =BEGINScaleRange: TYPE = CDVScale.ScaleRange;ScaleRec: TYPE = CDVScale.ScaleRec;MakeScale: PUBLIC PROC [off: CD.Position_[0, 0], nscale: ScaleRange_4, grid: INTEGER_-1] RETURNS [s: ScaleRec] =BEGINsE: INTEGER;noDivisionScale: ScaleRange = 8;scaleE: ARRAY ScaleRange OF INTEGER = --scale for factors[24, 16, 12, 8, 6, 4, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1];scaleF: ARRAY ScaleRange OF INTEGER = --scale for divisors[1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192]; scaleS: ARRAY ScaleRange OF NAT = --scale for shifts[0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];s.nscale _ nscale; --MIN[MAX[nscale, 0], CDVScale.scaleNum-1];s.grid _ MAX[1, grid];sE _ scaleE[s.nscale];s.sA _ scaleF[s.nscale];s.sB _ (s.grid/2)*sE+sE/2;s.sC _ sE*s.grid;s.sD _ s.grid;s.sS _ scaleS[s.nscale];s.off.x _ off.x/s.grid*s.grid;s.off.y _ off.y/s.grid*s.grid;IF s.useMultiply _ s.nscale<noDivisionScale THEN {s.xx _ sE;s.designToViewerFactor _ sE;}ELSE {s.xx _ s.sA;s.designToViewerFactor _ 1.0/s.sA;};END;GetClipRecord: PUBLIC PROC[scale: ScaleRec, highX, highY: CARDINAL] RETURNS [CD.Rect] =BEGINUnGridedScaleViewerToDesignUp: PROC [scale: ScaleRec, v: LONG CARDINAL] RETURNS [CD.Number] = INLINE {sE: INTEGER = IF scale.useMultiply THEN scale.xx ELSE 1;RETURN [LOOPHOLE[(v*scale.sA+sE+sE)/sE, CD.Number]]};RETURN [CD.Rect[x1: CDVScale.ViewerToDesignScalar[scale, 0]+scale.off.x,y1: CDVScale.ViewerToDesignScalar[scale, 0]+scale.off.y,x2: UnGridedScaleViewerToDesignUp[scale, highX+1]+scale.off.x,y2: UnGridedScaleViewerToDesignUp[scale, highY+1]+scale.off.y]]END;END.   °  CDVScaleImpl.mesaCopyright c 1983, 1984 by Xerox Corporation.  All rights reserved.by Christian Jacobi,  August 5, 1983 11:07 am redesigned by Christian Jacobi  August 28, 1984 9:19:36 am PDTlast edited by Christian Jacobi  January 27, 1986 5:06:53 pm PST--given the grid, offset and nscale; makes a correctly gridded and initialized ScaleRec--explanation of crazy scaling procedure for ScaleViewerToDesign--v * scale + offset         :: ideal--v* s1/s2 + offset          :: integer arithmetic--(v*s1 + s2/2) / s2 + offset  :: correct round of screen point--( (v*s1 + s2/2) / s2)  + grid/2) / grid * grid + offset  :: introduce grid--(v*s1 + s2/2 + grid/2*s2 ) / s2 / grid * grid + offset  --(v*s1 + s2/2 + grid/2*s2 ) / (s2*grid) * grid + offset--given the index of the (high-most) pixel in the viewer, compute an outside clipping --rectangle in design coordinates; (such that all outside the clipping area is invisible). ÊÇ  ˜ codešœ™Kšœ
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