/* * LineDDA * * Copyright 1993 Bob Amstadt */ #include <stdlib.h> #include "windef.h" #include "wingdi.h" #include "wine/wingdi16.h" /********************************************************************** * LineDDA (GDI32.248) */ BOOL WINAPI LineDDA(INT nXStart, INT nYStart, INT nXEnd, INT nYEnd, LINEDDAPROC callback, LPARAM lParam ) { INT xadd = 1, yadd = 1; INT err,erradd; INT cnt; INT dx = nXEnd - nXStart; INT dy = nYEnd - nYStart; if (dx < 0) { dx = -dx; xadd = -1; } if (dy < 0) { dy = -dy; yadd = -1; } if (dx > dy) { /* line is "more horizontal" */ err = 2*dy - dx; erradd = 2*dy - 2*dx; for(cnt = 0;cnt <= dx; cnt++) { callback(nXStart,nYStart,lParam); if (err > 0) { nYStart += yadd; err += erradd; } else { err += 2*dy; } nXStart += xadd; } } else { /* line is "more vertical" */ err = 2*dx - dy; erradd = 2*dx - 2*dy; for(cnt = 0;cnt <= dy; cnt++) { callback(nXStart,nYStart,lParam); if (err > 0) { nXStart += xadd; err += erradd; } else { err += 2*dx; } nYStart += yadd; } } return TRUE; }