Thuật toán DDA_Line dạng tổng quát

void hoanvi(int &a, int &b)
{	a = a ^ b;
	b = a ^ b;
	a = a ^ b;
}

// Hàm Line DDA ở dạng tổng quát.
void CGraphics::DrawLine_DDA_Full_2(int x1, int y1, int x2, int y2)
{	float dx, dy, x, y;
	float p;
	dx = x2 - x1;
	dy = y2 - y1;
	if(abs(dx) >= abs(dy))
	{	if(x1 > x2)
		{	hoanvi(x1, x2);
			hoanvi(y1, y2);
		}
		p = (float)(y2 - y1)/(x2 - x1);
		y = y1;
		for(x = x1; x < x2; x++)
		{	SetPixel(x, Round(y));
			y += p;
		}
	}
	else
	{	if(y1 > y2)
		{	hoanvi(x1, x2);
			hoanvi(y1, y2);
		}
		x = x1;
		p = (float)(x2 - x1)/(y2 - y1);
		for(y = y1; y < y2; y++)
		{	SetPixel(Round(x), y);
			x += p;
		}
	}
}

void CGraphics::DrawLine_DDA_Full(int x1, int y1, int x2, int y2)
{	
	CGraphics Point;
	float x,y,m;
	int dx=x2-x1, dy=y2-y1;
	if(dx==0 && dy==0)
		SetPixel(0,0,m_color);
	if(abs(dx) > abs(dy)) // Truong hop 1-2
	{
		m=float(dy)/dx;
		int k=dx > 0 ? 1:-1;
		x=x1; y=y1;
		for(int i=0;i
		{
			PutPixel(Round(x),Round(y),m_color);
			x+=k;
			y+=m*k;
		}
	}
	else
	{
		m=float(dx)/dy;
		int k = dy > 0 ? 1 : -1;
			x = x1; y = y1;
			for (int i=0; i
			{
				PutPixel(Round(x), Round(y), m_color);
				y += k;
				x += m*k;
			}
	}
}