C#数字图像处理算法学习笔记（三）--图像几何变换

//后台代码：
    public partial class Form1 : Form
    {
        private string _curFileName;
        private Bitmap _srcBitmap;
        private Bitmap _dstBitmap;

        public Form1()
        {
            InitializeComponent();
        }

        private void open_Click(object sender, EventArgs e)
        {
            OpenFileDialog opnDlg = new OpenFileDialog();
            opnDlg.Filter = @"所有图像文件|*.bmp;*.pcx;*.png;*.jpg;*.gif;" + @"*.tif;*.ico;*.dxf;*.cgm;*.cdr;*.wmf;*;eps;*.emf|" +
                            @"位图(*.bmp;*.jpg;*.png;...)|*.bmp;*.pcx;*.png;*.jpg;*.gif;*.tif;*.ico|" +
                            @"矢量图(*.wmf;*.eps;*.emf;...)|*.dxf;*.cgm;*.wmf;*.eps;*.emf";
            opnDlg.Title = @"打开图像文件";
            opnDlg.ShowHelp = true;
            if (opnDlg.ShowDialog() == DialogResult.OK)
            {
                _curFileName = opnDlg.FileName;
                try
                {
                    _srcBitmap = (Bitmap) Image.FromFile(_curFileName);
                }
                catch (Exception ee)
                {
                    MessageBox.Show(ee.Message);
                }
            }
            Invalidate();
        }

        private void close_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            if (_srcBitmap != null)
            {
                g.DrawImage(_srcBitmap, 160, 20, _srcBitmap.Width, _srcBitmap.Height);
            }
        }

　　　　//翻转处理函数，这里是通过两幅图来进行翻转操作，也可以用一幅图直接翻转，只不过要特别注意每个像素占3个byte位，且翻转时是整个像素一起翻转
        private void mirror_Click(object sender, EventArgs e)
        {
            if (_srcBitmap != null)
            {
                _dstBitmap = (Bitmap) _srcBitmap.Clone();
                BitmapData bmpData = _srcBitmap.LockBits(new Rectangle(0, 0, _srcBitmap.Width, _srcBitmap.Height),
                    ImageLockMode.ReadWrite,
                    _srcBitmap.PixelFormat);
                BitmapData dstData = _dstBitmap.LockBits(new Rectangle(0, 0, _dstBitmap.Width, _dstBitmap.Height),
                    ImageLockMode.ReadWrite, _dstBitmap.PixelFormat);

                unsafe
                {
                    byte* p = (byte*) bmpData.Scan0;

                    for (int y = 0; y < bmpData.Height; y++)
                    {
                        for (int x = 0; x < bmpData.Width; x++)
                        {
                            byte* dstp = (byte*) dstData.Scan0 + y*dstData.Stride + x*3;
                            dstp[0] = p[bmpData.Width*3 - (x + 1)*3]; 
                            dstp[1] = p[bmpData.Width*3 - (x + 1)*3 + 1];
                            dstp[2] = p[bmpData.Width*3 - (x + 1)*3 + 2];
                        }
                        p += bmpData.Stride;    //Stride 为扫描宽度 Stride > bmpData.Width * 3 ,Width 表示每行的像素个数，每个像素占3个byte位
                    }

                    _srcBitmap.UnlockBits(bmpData);
                    _dstBitmap.UnlockBits(dstData);
                }

                _srcBitmap = (Bitmap) _dstBitmap.Clone();
                Invalidate();
            }
        }
    }