148505Sbostic /*- 2*61365Sbostic * Copyright (c) 1980, 1993 3*61365Sbostic * The Regents of the University of California. All rights reserved. 448505Sbostic * 548505Sbostic * %sccs.include.proprietary.c% 619971Sdist */ 719971Sdist 815442Sralph #ifndef lint 9*61365Sbostic static char sccsid[] = "@(#)subr.c 8.1 (Berkeley) 06/04/93"; 1048505Sbostic #endif /* not lint */ 1115442Sralph 1215442Sralph #include "dumb.h" 1315442Sralph 1415442Sralph /* Does not plot first point -- assumed that it is already plotted */ 1515442Sralph dda_line(ch, x0, y0, x1, y1) 1615442Sralph char ch; 1715442Sralph int x0, y0; /* already transformed to screen coords */ 1815442Sralph int x1, y1; /* untransformed */ 1915442Sralph { 2015442Sralph int length, i; 2115442Sralph double deltaX, deltaY; 2215442Sralph double x, y; 2315442Sralph double floor(); 2415442Sralph int abs(); 2515442Sralph 2615442Sralph scale(x1, y1); 2715442Sralph 2815442Sralph length = abs(x1 - x0); 2915442Sralph if (abs(y1 -y0) > length) 3015442Sralph length = abs(y1 - y0); 3115442Sralph 3215442Sralph if (length == 0) 3315442Sralph return; 3415442Sralph 3515442Sralph deltaX = (double) (x1 - x0)/(double) length; 3615442Sralph deltaY = (double) (y1 - y0)/(double) length; 3715442Sralph 3815442Sralph x = (double) x0 + 0.5; 3915442Sralph y = (double) y0 + 0.5; 4015442Sralph 4115442Sralph for (i=0; i < length; ++i) { 4215442Sralph x += deltaX; 4315442Sralph y += deltaY; 4415442Sralph x0 = floor(x); 4515442Sralph y0 = floor(y); 4615442Sralph currentx = x0; 4715442Sralph currenty = y0; 4815442Sralph screenmat[currentx][currenty] = ch; 4915442Sralph } 5015442Sralph } 51