数字图像处理 几何变换（平移、水平镜像、垂直镜像、缩放、旋转）实现思路

// dd为新的图像指针，sd为旧的图像指针
// 水平镜像
BOOL LImageProc::FlipH()
{
	if (!ImageIsValid()) return FALSE;
	m_pDestImg->Create(m_pSrcImg->m_Width, m_pSrcImg->m_Height);
	BYTE *sd = m_pSrcImg->m_pBits;
	BYTE *dd = m_pDestImg->m_pBits;
	for (int i = 0; i < m_pDestImg->m_Height; i++)
	{
		for (int j = 0; j < m_pDestImg->m_Width * 3; j += 3)
		{
			for (int k = 0; k < 3; k++)
			{
				dd[i*m_pDestImg->m_WidthBytes + j + k] = sd[i*m_pDestImg->m_WidthBytes + m_pDestImg->m_WidthBytes - j + k - 3];
			}
		}
	}
	return TRUE;
}

// 垂直镜像
BOOL LImageProc::FlipV()
{
	if (!ImageIsValid()) return FALSE;
	m_pDestImg->Create(m_pSrcImg->m_Width, m_pSrcImg->m_Height);
	BYTE *sd = m_pSrcImg->m_pBits;
	BYTE *dd = m_pDestImg->m_pBits;
	for (int i = 0; i < m_pDestImg->m_Height; i++)
	{
		for (int j = 0; j < m_pDestImg->m_Width * 3; j += 3)
		{
			dd[i*m_pDestImg->m_WidthBytes + j] = sd[(m_pDestImg->m_Height - i - 1)*m_pDestImg->m_WidthBytes + j];
			dd[i*m_pDestImg->m_WidthBytes + j + 1] = sd[(m_pDestImg->m_Height - i - 1)*m_pDestImg->m_WidthBytes + j + 1];
			dd[i*m_pDestImg->m_WidthBytes + j + 2] = sd[(m_pDestImg->m_Height - i - 1)*m_pDestImg->m_WidthBytes + j + 2];
		}
	}

	return TRUE;
}

// 缩放
BOOL LImageProc::Stretch(float aW, float aH)
{
	if (!ImageIsValid()) return FALSE;
	m_pDestImg->Create((int)m_pSrcImg->m_Width*aW, (int)m_pSrcImg->m_Height*aH);
	BYTE *sd = m_pSrcImg->m_pBits;
	BYTE *dd = m_pDestImg->m_pBits;
	int newX = 1;
	int newY = 1;
	for (int i = 0; i < m_pDestImg->m_Height; i++)
	{
		for (int j = 0; j < m_pDestImg->m_Width * 3; j += 3)
		{
			newX = (int)(j / aW);
			newY = (int)(i / aH);
			dd[i*m_pDestImg->m_WidthBytes + j] = sd[newY*m_pSrcImg->m_WidthBytes + newX];
			dd[i*m_pDestImg->m_WidthBytes + j + 1] = sd[newY*m_pSrcImg->m_WidthBytes + newX + 1];
			dd[i*m_pDestImg->m_WidthBytes + j + 2] = sd[newY*m_pSrcImg->m_WidthBytes + newX + 2];
		}
	}
}

// 平移
BOOL LImageProc::Translate(int Hori, int Vert)
{
	if (Hori > m_pSrcImg->m_Width || Vert > m_pSrcImg->m_Height)
	{
		AfxMessageBox("图像平移不能超过原始长度:", MB_OK, 0);
		return FALSE;
	}
	if (!ImageIsValid()) return FALSE;
	m_pDestImg->Create((int)m_pSrcImg->m_Width, (int)m_pSrcImg->m_Height);
	BYTE *sd = m_pSrcImg->m_pBits;
	BYTE *dd = m_pDestImg->m_pBits;

	int x, y;

	for (y = 0; y < m_pDestImg->m_Height; y++)
	{

		if (((y < Vert) && (Vert >= 0)) || ((y >= (m_pDestImg->m_Height + Vert)) && (Vert < 0)))
		{
			for (x = 0; x < m_pDestImg->m_Width * 3; x += 3)
			{
				dd[y*m_pDestImg->m_WidthBytes + x] = 255;
				dd[y*m_pDestImg->m_WidthBytes + x + 1] = 255;
				dd[y*m_pDestImg->m_WidthBytes + x + 2] = 255;
			}
		}
		else if (((y >= Vert) && (Vert >= 0)) || ((y < (m_pDestImg->m_Height + Vert)) && (Vert < 0)))
		{
			for (x = 0; x < m_pDestImg->m_Width * 3; x += 3)
			{
				// 右移
				if (Hori >= 0) {
					if (x < 3 * Hori)
					{
						dd[y*m_pDestImg->m_WidthBytes + x] = 255;
						dd[y*m_pDestImg->m_WidthBytes + x + 1] = 255;
						dd[y*m_pDestImg->m_WidthBytes + x + 2] = 255;
					}
					else if (x >= 3 * Hori)
					{
						dd[y*m_pDestImg->m_WidthBytes + x] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3];
						dd[y*m_pDestImg->m_WidthBytes + x + 1] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3 + 1];
						dd[y*m_pDestImg->m_WidthBytes + x + 2] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3 + 2];
					}
				}
				// 左移动
				else {
					if (x >= (m_pDestImg->m_WidthBytes + 3 * Hori))
					{
						dd[y*m_pDestImg->m_WidthBytes + x] = 255;
						dd[y*m_pDestImg->m_WidthBytes + x + 1] = 255;
						dd[y*m_pDestImg->m_WidthBytes + x + 2] = 255;
					}
					else
					{
						dd[y*m_pDestImg->m_WidthBytes + x] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3];
						dd[y*m_pDestImg->m_WidthBytes + x + 1] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3 + 1];
						dd[y*m_pDestImg->m_WidthBytes + x + 2] = sd[(y - Vert)*m_pDestImg->m_WidthBytes + x - Hori * 3 + 2];
					}
				}
			}
		}
	}
	return TRUE;
}