Question

再C#中QQ截图的代码怎么写

再C#中QQ截图的代码怎么写

Answer 1

 QQ截图的核心其实就是调用WINDOWS API函数，主要涉及两个核心组件, user32.dll和gdi32.dll。

如下是，C#代码调用上述两个核心组件的完整示例：

namespace WindowsFormsApplication1
{
    /// <summary>
    /// 屏幕捕获类 
    /// </summary>
    public class ScreenCapture
    {
        /// <summary>
        /// 创建一个包含整个桌面的截图Image对象(捕获到的桌面是当前WINDOWS操作系统活动桌面)
        /// </summary>
        /// <returns></returns>
        public Image CaptureScreen()
        {
            return CaptureWindow(User32.GetDesktopWindow());
        }

        /// <summary>
        /// 创建一个包含特定窗口的截图Image对象
        /// </summary>
        /// <param name="handle">启动本程序的句柄窗口(在Windows上这是由Handle属性获得）</param>
        /// <returns></returns>
        public Image CaptureWindow(IntPtr handle)
        {
            // 获取目标窗口的HDC
            IntPtr hdcSrc = User32.GetWindowDC(handle);
            // 获取它的大小
            User32.RECT windowRect = new User32.RECT();
            User32.GetWindowRect(handle, ref windowRect);
            int width = windowRect.right - windowRect.left;
            int height = windowRect.bottom - windowRect.top;
            // 创建设备上下文对象
            IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);

            IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height);

            IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap);

            GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY);

            GDI32.SelectObject(hdcDest, hOld);

            GDI32.DeleteDC(hdcDest);
            User32.ReleaseDC(handle, hdcSrc);

            Image img = Image.FromHbitmap(hBitmap);

            GDI32.DeleteObject(hBitmap);

            return img;
        }

        /// <summary>
        /// 获取特定窗口，并保存它
        /// </summary>
        /// <param name="handle"></param>
        /// <param name="filename"></param>
        /// <param name="format"></param>
        public void CaptureWindowToFile(IntPtr handle, string filename, ImageFormat format)
        {
            Image img = CaptureWindow(handle);
            img.Save(filename, format);
        }

        /// <summary>
        /// 捕获整个windows活动窗口并保存它
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="format"></param>
        public void CaptureScreenToFile(string filename, ImageFormat format)
        {
            Image img = CaptureScreen();
            img.Save(filename, format);
        }

        /// <summary>
        /// GDI32 相关的API函数
        /// </summary>
        private class GDI32
        {

            public const int SRCCOPY = 0x00CC0020;  

            [DllImport("gdi32.dll")]
            public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,
                int nWidth, int nHeight, IntPtr hObjectSource,
                int nXSrc, int nYSrc, int dwRop);
            [DllImport("gdi32.dll")]
            public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,
                int nHeight);
            [DllImport("gdi32.dll")]
            public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
            [DllImport("gdi32.dll")]
            public static extern bool DeleteDC(IntPtr hDC);
            [DllImport("gdi32.dll")]
            public static extern bool DeleteObject(IntPtr hObject);
            [DllImport("gdi32.dll")]
            public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
        }

        /// <summary>
        /// User32 API相关函数
        /// </summary>
        private class User32
        {
            [StructLayout(LayoutKind.Sequential)]
            public struct RECT
            {
                public int left;
                public int top;
                public int right;
                public int bottom;
            }

            [DllImport("user32.dll")]
            public static extern IntPtr GetDesktopWindow();
            [DllImport("user32.dll")]
            public static extern IntPtr GetWindowDC(IntPtr hWnd);
            [DllImport("user32.dll")]
            public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
            [DllImport("user32.dll")]
            public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);

        }


    }

}
//  调用示例：
private void button1_Click(object sender, EventArgs e)
        {
            ScreenCapture sc = new ScreenCapture();
            // 捕获整个屏幕并保存到一个文件里
            Image img = sc.CaptureScreen();
            // 将捕获的图片显示在图片控件里
            this.pictureBox1.Image = img;
            // 捕获当前运行窗体并保存在C盘,文件名和后缀为temp.png
            sc.CaptureWindowToFile(this.Handle, "C:\\temp.png", ImageFormat.Gif);
        }

Answer 2

普通全屏截图 把图片加载到自己的窗体中显示 窗体大小为全屏，且置顶。然后根据用户鼠标绘制矩形来截取图片