C# 图像处理(一)（图像缩放、屏幕截取、图像合并、保存图像）

示例：

Image screen = getScreen();                       // 截取屏幕saveImage(screen, screen.Size, @"d:\截屏.jpg");   // 保存截屏

# region 图像处理功能函数/// <summary>/// 按指定尺寸对图像pic进行非拉伸缩放/// </summary>public static Bitmap shrinkTo(Image pic, Size S, Boolean cutting){    //创建图像    Bitmap tmp = new Bitmap(S.Width, S.Height);     //按指定大小创建位图    //绘制    Graphics g = Graphics.FromImage(tmp);           //从位图创建Graphics对象    g.Clear(Color.FromArgb(0, 0, 0, 0));            //清空    Boolean mode = (float)pic.Width / S.Width > (float)pic.Height / S.Height;   //zoom缩放    if (cutting) mode = !mode;                      //裁切缩放    //计算Zoom绘制区域                 if (mode)        S.Height = (int)((float)pic.Height * S.Width / pic.Width);    else        S.Width = (int)((float)pic.Width * S.Height / pic.Height);    Point P = new Point((tmp.Width - S.Width) / 2, (tmp.Height - S.Height) / 2);    g.DrawImage(pic, new Rectangle(P, S));    return tmp;     //返回构建的新图像}//保存图像pic到文件fileName中，指定图像保存格式public static void SaveToFile(Image pic, string fileName, bool replace, ImageFormat format)    //ImageFormat.Jpeg{    //若图像已存在，则删除    if (System.IO.File.Exists(fileName) && replace)        System.IO.File.Delete(fileName);    //若不存在则创建    if (!System.IO.File.Exists(fileName))    {        if (format == null) format = getFormat(fileName);   //根据拓展名获取图像的对应存储类型        if (format == ImageFormat.MemoryBmp) pic.Save(fileName);        else pic.Save(fileName, format);                    //按给定格式保存图像    }}//根据文件拓展名，获取对应的存储类型public static ImageFormat getFormat(string filePath){    ImageFormat format = ImageFormat.MemoryBmp;    String Ext = System.IO.Path.GetExtension(filePath).ToLower();    if (Ext.Equals(".png")) format = ImageFormat.Png;    else if (Ext.Equals(".jpg") || Ext.Equals(".jpeg")) format = ImageFormat.Jpeg;    else if (Ext.Equals(".bmp")) format = ImageFormat.Bmp;    else if (Ext.Equals(".gif")) format = ImageFormat.Gif;    else if (Ext.Equals(".ico")) format = ImageFormat.Icon;    else if (Ext.Equals(".emf")) format = ImageFormat.Emf;    else if (Ext.Equals(".exif")) format = ImageFormat.Exif;    else if (Ext.Equals(".tiff")) format = ImageFormat.Tiff;    else if (Ext.Equals(".wmf")) format = ImageFormat.Wmf;    else if (Ext.Equals(".memorybmp")) format = ImageFormat.MemoryBmp;    return format;}[DllImport("user32.dll")]static extern bool GetCursorInfo(out CURSORINFO pci);private const Int32 CURSOR_SHOWING = 0x00000001;[StructLayout(LayoutKind.Sequential)]struct POINT{    public Int32 x;    public Int32 y;}[StructLayout(LayoutKind.Sequential)]struct CURSORINFO{    public Int32 cbSize;    public Int32 flags;    public IntPtr hCursor;    public POINT ptScreenPos;}/// <summary>/// 截取屏幕指定区域为Image，保存到路径savePath下，haveCursor是否包含鼠标/// </summary>public static Image getScreen(int x = 0, int y = 0, int width = -1, int height = -1, String savePath = "", bool haveCursor = true){    if (width == -1) width = SystemInformation.VirtualScreen.Width;    if (height == -1) height = SystemInformation.VirtualScreen.Height;    Bitmap tmp = new Bitmap(width, height);                 //按指定大小创建位图    Graphics g = Graphics.FromImage(tmp);                   //从位图创建Graphics对象    g.CopyFromScreen(x, y, 0, 0, new Size(width, height));  //绘制    // 绘制鼠标    if (haveCursor)    {        try        {            CURSORINFO pci;            pci.cbSize = Marshal.SizeOf(typeof(CURSORINFO));            GetCursorInfo(out pci);            System.Windows.Forms.Cursor cur = new System.Windows.Forms.Cursor(pci.hCursor);            cur.Draw(g, new Rectangle(pci.ptScreenPos.x, pci.ptScreenPos.y, cur.Size.Width, cur.Size.Height));        }        catch (Exception ex) { }    // 若获取鼠标异常则不显示    }    //Size halfSize = new Size((int)(tmp.Size.Width * 0.8), (int)(tmp.Size.Height * 0.8));  // 按一半尺寸存储图像    if (!savePath.Equals("")) saveImage(tmp, tmp.Size, savePath);       // 保存到指定的路径下    return tmp;     //返回构建的新图像}/// <summary>/// 缩放icon为指定的尺寸，并保存到路径PathName/// </summary>public static void saveImage(Image image, Size size, String PathName){    Image tmp = shrinkTo(image, size, false);    SaveToFile(tmp, PathName, true, null);}# endregion