don't throw away float <-> double conversions for FORTRAN.

[unix-history] / usr / src / old / lib2648 / update.c

/*      update.c        4.1     83/03/09        */
/*
* update: the key output optimization routine of the whole editor.
* The input consists of two bit matrices (mold is what's on the screen,
* mnew is what we want to be on the screen) and the coordinates of
* the lower left corner on the screen where this matrix is.
* This routine does whatever is necessary to get the screen to look
* like mnew, assuming that it currently looks like mold.
*
* (If I could patent this process for bread and other food I
* would be a rich man.)
*/

#include "bit.h"

update(mold, mnew, rows, cols, baser, basec)
bitmat mold, mnew;
int rows, cols, baser, basec;
{
       int irow;
       register int i, j, k;
       int r1, r2, c1, c2, nr1, nr2, nc1, nc2;
       extern int QUIET;

#ifdef TRACE
       if (trace)
               fprintf(trace, "update(mold=%x, mnew=%x, rows=%d, cols=%d, baser=%d, basec=%d)\n", mold, mnew, rows, cols, baser, basec);
#endif

       if (QUIET)
               return;
       aminmax(mold, rows, cols, &r1, &c1, &r2, &c2);
       aminmax(mnew, rows, cols, &nr1, &nc1, &nr2, &nc2);
       r1 = min(r1, nr1); r2 = max(r2, nr2);
       c1 = min(c1, nc1); c2 = max(c2, nc2);

       dumpmat("mold:", mold, rows, cols);
       dumpmat("mnew:", mnew, rows, cols);

       for (i=r1; i<=r2; i++) {
               irow = baser + rows - i - 1;
               if (emptyrow(mnew, rows, cols, i)) {
                       if (emptyrow(mold, rows, cols, i)) {
                               continue;       /* identically blank. skip. */
                       }
                       /*
                        * Row i is to be cleared.  Look for some more
                        * rows to clear and do it all at once.
                        */
                       for (j=i+1; j<rows && emptyrow(mnew,rows,cols,j); j++)
                               ;
                       areaclear(baser+rows-j, basec, irow, basec+cols-1);
                       i = j-1;        /* skip the others */
               } else for (j=c1; j<=c2; j++) {
                       /*
                        * Result row is not all blank.  We look for stretches
                        * of bits that have to be changed (in either
                        * direction) and draw an exclusive or line over all
                        * the bits in each stretch.
                        */
                       if (mat(mold,rows,cols,i,j,1)!=mat(mnew,rows,cols,i,j,2)){
                               for (k=j+1; k<cols && mat(mold,rows,cols,i,k,3)!=
                                       mat(mnew,rows,cols,i,k,4); k++)
                                       ;
                               k--;
                               setxor();
                               line(basec+j, irow, basec+k, irow);
                               j = k;  /* skip the others */
                       }
               }
       }
}