void inc_line(int x1, int y1, int x2, int y2, int color){
int dx, dy, incE, incNE, d, x, y;
dx = x2 - x1;
dy = y2 - y1;
d = 2 * dy - dx; /* Valor inicial de d */
incE = 2 * dy; /* Incremento de E */
incNE = 2 * (dy - dx); /* Incremento de NE */
x = x1;
y = y1;
write_pixel(x, y, color);
while (x < x2){
if (d <= 0) {
/* Escolhe E */
d = d + incE;
x = x + 1;
}else{
/* Escolhe NE */
d = d + incNE;
x = x + 1;
y = y + 1;
}/* end if */
write_pixel(x, y, color);
}/* end while */
}/* end inc_line */