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Annotation of 43BSD/usr.lib/lib2648/update.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1980 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  */
                      6: 
                      7: #ifndef lint
                      8: static char sccsid[] = "@(#)update.c   5.1 (Berkeley) 4/26/85";
                      9: #endif not lint
                     10: 
                     11: /*
                     12:  * update: the key output optimization routine of the whole editor.
                     13:  * The input consists of two bit matrices (mold is what's on the screen,
                     14:  * mnew is what we want to be on the screen) and the coordinates of
                     15:  * the lower left corner on the screen where this matrix is.
                     16:  * This routine does whatever is necessary to get the screen to look
                     17:  * like mnew, assuming that it currently looks like mold.
                     18:  *
                     19:  * (If I could patent this process for bread and other food I
                     20:  * would be a rich man.)
                     21:  */
                     22: 
                     23: #include "bit.h"
                     24: 
                     25: update(mold, mnew, rows, cols, baser, basec)
                     26: bitmat mold, mnew;
                     27: int rows, cols, baser, basec;
                     28: {
                     29:        int irow;
                     30:        register int i, j, k;
                     31:        int r1, r2, c1, c2, nr1, nr2, nc1, nc2;
                     32:        extern int QUIET;
                     33: 
                     34: #ifdef TRACE
                     35:        if (trace)
                     36:                fprintf(trace, "update(mold=%x, mnew=%x, rows=%d, cols=%d, baser=%d, basec=%d)\n", mold, mnew, rows, cols, baser, basec);
                     37: #endif
                     38: 
                     39:        if (QUIET)
                     40:                return;
                     41:        aminmax(mold, rows, cols, &r1, &c1, &r2, &c2);
                     42:        aminmax(mnew, rows, cols, &nr1, &nc1, &nr2, &nc2);
                     43:        r1 = min(r1, nr1); r2 = max(r2, nr2);
                     44:        c1 = min(c1, nc1); c2 = max(c2, nc2);
                     45: 
                     46:        dumpmat("mold:", mold, rows, cols);
                     47:        dumpmat("mnew:", mnew, rows, cols);
                     48: 
                     49:        for (i=r1; i<=r2; i++) {
                     50:                irow = baser + rows - i - 1;
                     51:                if (emptyrow(mnew, rows, cols, i)) {
                     52:                        if (emptyrow(mold, rows, cols, i)) {
                     53:                                continue;       /* identically blank. skip. */
                     54:                        }
                     55:                        /*
                     56:                         * Row i is to be cleared.  Look for some more
                     57:                         * rows to clear and do it all at once.
                     58:                         */
                     59:                        for (j=i+1; j<rows && emptyrow(mnew,rows,cols,j); j++)
                     60:                                ;
                     61:                        areaclear(baser+rows-j, basec, irow, basec+cols-1);
                     62:                        i = j-1;        /* skip the others */
                     63:                } else for (j=c1; j<=c2; j++) {
                     64:                        /*
                     65:                         * Result row is not all blank.  We look for stretches
                     66:                         * of bits that have to be changed (in either
                     67:                         * direction) and draw an exclusive or line over all
                     68:                         * the bits in each stretch.
                     69:                         */
                     70:                        if (mat(mold,rows,cols,i,j,1)!=mat(mnew,rows,cols,i,j,2)){
                     71:                                for (k=j+1; k<cols && mat(mold,rows,cols,i,k,3)!=
                     72:                                        mat(mnew,rows,cols,i,k,4); k++)
                     73:                                        ;
                     74:                                k--;
                     75:                                setxor();
                     76:                                line(basec+j, irow, basec+k, irow);
                     77:                                j = k;  /* skip the others */
                     78:                        }
                     79:                }
                     80:        }
                     81: }

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