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/*
* LineDDA
*
* Copyright 1993 Bob Amstadt
*/
#include <stdlib.h>
#include "windows.h"
/**********************************************************************
* LineDDA16 (GDI.100)
*/
void WINAPI LineDDA16( INT16 nXStart, INT16 nYStart, INT16 nXEnd, INT16 nYEnd,
LINEDDAPROC16 callback, LPARAM lParam )
{
LineDDA32( nXStart, nYStart, nXEnd, nYEnd,
(LINEDDAPROC32)callback, lParam );
}
/**********************************************************************
* LineDDA32 (GDI32.248)
*/
BOOL32 WINAPI LineDDA32(INT32 nXStart, INT32 nYStart, INT32 nXEnd, INT32 nYEnd,
LINEDDAPROC32 callback, LPARAM lParam )
{
INT32 xadd = 1, yadd = 1;
INT32 err,erradd;
INT32 cnt;
INT32 dx = nXEnd - nXStart;
INT32 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;
}
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