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/*
* Code to scale dimensions. Takes two thirty-two bit integers, multiplies
* them, divides them by 2^20, and returns the thirty-two bit result.
* The first integer, the width in FIXes, can lie between -2^24 and 2^24-1.
* The second integer, the scale factor, can lie between 0 and 2^27-1.
*
* Here, unlike in TeX, we do the arithmetic exactly. Since the error
* in the TeX arithmetic is parts per million, and since dvips makes no
* layout decisions, this has no effect. (TeX stipulates that any
* implementation of *TeX* needs to do the arithmetic exactly as
* specified in TeX, but drivers need not.)
*
* Since this math is special, we put it in its own file. It is the only
* place in the program where such accuracy is required.
*/
#include "dvips.h" /* The copyright notice in that file is included too! */
/*
* The external declarations:
*/
#include "protos.h"
integer
scalewidth(register integer a, register integer b)
{
register integer al, bl;
if (a < 0)
return -scalewidth(-a, b);
if (b < 0)
return -scalewidth(a, -b);
al = a & 32767;
bl = b & 32767;
a >>= 15;
b >>= 15;
return ( ((al*bl/32768) + a*bl+al*b)/32 + a*b*1024);
}
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