C#图像镜像

C#水平垂直图像镜像---C#数字图像处理算法典型实例.赵春江

原理：

变换前

           灰度图像--->像素序号=c+r*w（当前列+当前行*列数）

            彩色图像--->像素序号=0+c*3+r*w*3

                                  像素序号=1+c*3+r*w*3

                                  像素序号=2+c*3+r*w*3

变换后参考代码

private void start_Click(object sender, EventArgs e)
        {
            Rectangle rect= new Rectangle(0,0,_bmp.Width,_bmp.Height);
            BitmapData bmpdata = _bmp.LockBits(rect, ImageLockMode.ReadWrite, _bmp.PixelFormat);
            IntPtr ptr = bmpdata.Scan0;
            int bytes=0;
            if(_bmp.PixelFormat==PixelFormat.Format8bppIndexed)//判断是灰度色图像还是彩色图像，给相应的大小
            {
                bytes=_bmp.Width*_bmp.Height;
            }
            else if(_bmp.PixelFormat==PixelFormat.Format24bppRgb)
            {
                bytes = _bmp.Width * _bmp.Height * 3;
            }

            byte[] pixelValues=new byte[bytes];
            System.Runtime.InteropServices.Marshal.Copy(ptr, pixelValues, 0, bytes);//内存法，从内存中将像素复制到pixelValues数组

            int halfWidth = _bmp.Width / 2;
            int halfheigth= _bmp.Height/2;
            byte temp;
            byte temp1;
            byte temp2;
            //灰度图像
            if (_bmp.PixelFormat==PixelFormat.Format8bppIndexed)
            {
                if (HorV)
                {
                    for (int r = 0; r < _bmp.Height; r++)
                        for (int c = 0; c < halfWidth; c++)
                        {
                            temp = pixelValues[r * _bmp.Width + c];
                            pixelValues[r * _bmp.Width + c] = pixelValues[(r + 1) * _bmp.Width - c - 1];
                            pixelValues[(r + 1) * _bmp.Width - c - 1] = temp;
                        }                    
                }
                else
                {
                    for (int c = 0; c < _bmp.Width; c++)
                    {
                        for (int r = 0; r < halfheigth; r++)
                        {
                            temp = pixelValues[r * _bmp.Width + c];
                            pixelValues[r * _bmp.Width + c] = pixelValues[(_bmp.Height - r - 1) * _bmp.Width + c];
                            pixelValues[(_bmp.Height - r - 1) * _bmp.Width + c] = temp;
                        }
                    }
                }
            }
            else if (_bmp.PixelFormat == PixelFormat.Format24bppRgb)//彩色图像
            {
                if (HorV)
                {
                    for (int r = 0; r < _bmp.Height; r++)
                        for (int c = 0; c < halfWidth; c++)
                        {
                            temp  = pixelValues[0 + r * _bmp.Width * 3 + c * 3];
                            temp1 = pixelValues[1 + r * _bmp.Width * 3 + c * 3];
                            temp2 = pixelValues[2 + r * _bmp.Width * 3 + c * 3];
                            pixelValues[0 + r * _bmp.Width * 3 + c * 3] = pixelValues[0 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3];
                            pixelValues[1 + r * _bmp.Width * 3 + c * 3] = pixelValues[1 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3];
                            pixelValues[2 + r * _bmp.Width * 3 + c * 3] = pixelValues[2 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3];
                            pixelValues[0 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3]=temp;
                            pixelValues[1 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3]=temp1;
                            pixelValues[2 + (r + 1) * _bmp.Width * 3 - (c + 1) * 3] = temp2;
                        }
                }
                else
                {
                    for (int c = 0; c < _bmp.Width; c++)
                    {
                        for (int r = 0; r < halfheigth; r++)
                        {
                            temp  = pixelValues[0 + r * _bmp.Width * 3 + c * 3];
                            temp1 = pixelValues[1 + r * _bmp.Width * 3 + c * 3];
                            temp2 = pixelValues[2 + r * _bmp.Width * 3 + c * 3];
                            pixelValues[0 + r * _bmp.Width * 3 + c * 3] = pixelValues[0 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3];
                            pixelValues[1 + r * _bmp.Width * 3 + c * 3] = pixelValues[1 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3];
                            pixelValues[2 + r * _bmp.Width * 3 + c * 3] = pixelValues[2 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3];
                            pixelValues[0 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3] = temp;
                            pixelValues[1 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3] = temp1;
                            pixelValues[2 + (_bmp.Height - r - 1) * _bmp.Width * 3 + c * 3] = temp2;
                        }
                    }
                }
            }

            System.Runtime.InteropServices.Marshal.Copy(pixelValues, 0, ptr, bytes);
            _bmp.UnlockBits(bmpdata);

            _pictureBox.Image = _bmp;

水平镜像效果

垂直镜像效果

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