50 lines
1.0 KiB
C
50 lines
1.0 KiB
C
/*
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* Copyright (c) 1980 Regents of the University of California.
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* All rights reserved. The Berkeley software License Agreement
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* specifies the terms and conditions for redistribution.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)subr.c 1.1 94/10/31 SMI"; /* from UCB 5.1 5/7/85 */
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#endif not lint
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#include "dumb.h"
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/* Does not plot first point -- assumed that it is already plotted */
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dda_line(ch, x0, y0, x1, y1)
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char ch;
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int x0, y0; /* already transformed to screen coords */
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int x1, y1; /* untransformed */
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{
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int length, i;
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double deltaX, deltaY;
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double x, y;
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double floor();
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int abs();
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scale(x1, y1);
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length = abs(x1 - x0);
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if (abs(y1 -y0) > length)
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length = abs(y1 - y0);
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if (length == 0)
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return;
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deltaX = (double) (x1 - x0)/(double) length;
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deltaY = (double) (y1 - y0)/(double) length;
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x = (double) x0 + 0.5;
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y = (double) y0 + 0.5;
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for (i=0; i < length; ++i) {
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x += deltaX;
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y += deltaY;
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x0 = floor(x);
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y0 = floor(y);
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currentx = x0;
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currenty = y0;
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screenmat[currentx][currenty] = ch;
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}
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}
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