我想要相对自由的方式来做到这一点,有什么想法吗?例如,以下内容截取了不包含半透明窗口的屏幕截图:
Public Class Form1 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Shown Text = "Opaque Window" Dim win2 As New Form win2.Opacity = 0.5 win2.Text = "Tranparent Window" win2.Show() win2.Top = Top + 50 win2.Left = Left() + 50 Dim bounds As Rectangle = System.Windows.Forms.Screen.GetBounds(Point.Empty) Using bmp As Bitmap = New Bitmap(bounds.Width, bounds.Height) Using g As Graphics = Graphics.FromImage(bmp) g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size) End Using bmp.Save("c:\temp\scn.gif") End Using Process.Start(New Diagnostics.ProcessStartInfo("c:\temp\scn.gif") With {.UseShellExecute = True}) End Sub End Class
我的Google- fu真的很烂,或者听起来并不容易。我很确定为什么会发生这种情况,因为视频驱动程序必须分开内存才能完成这项工作,但是我不在乎为什么它行不通,我只想在没有它的情况下做… 印刷屏幕按键破解 第三方软件 * SDK功能尚可,但我会投票支持用户拥有的每个对象,这些对象可以在纯框架中向我展示(只是开个玩笑,但会很好)。
如果这是唯一的方法,那么我如何在VB中这样做呢? 1M谢谢。
设置了TransparencyKey或Opacity属性的表单是所谓的分层窗口。使用视频适配器的“覆盖”功能显示它们。这使他们能够具有透明效果。
捕获它们需要在CopyFromScreen重载中打开CopyPixelOperation.CaptureBlt选项,该重载接受CopyPixelOperation参数。
不幸的是,此重载有一个严重的错误,阻止了它的正常运行。它无法正确验证该值。仍未在.NET 4.0中修复。没有其他好的修复方法,只能使用P / Invoke进行屏幕截图。这是一个例子:
using System; using System.Drawing; using System.Windows.Forms; using System.Runtime.InteropServices; namespace WindowsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { Size sz = Screen.PrimaryScreen.Bounds.Size; IntPtr hDesk = GetDesktopWindow(); IntPtr hSrce = GetWindowDC(hDesk); IntPtr hDest = CreateCompatibleDC(hSrce); IntPtr hBmp = CreateCompatibleBitmap(hSrce, sz.Width, sz.Height); IntPtr hOldBmp = SelectObject(hDest, hBmp); bool b = BitBlt(hDest, 0, 0, sz.Width, sz.Height, hSrce, 0, 0, CopyPixelOperation.SourceCopy | CopyPixelOperation.CaptureBlt); Bitmap bmp = Bitmap.FromHbitmap(hBmp); SelectObject(hDest, hOldBmp); DeleteObject(hBmp); DeleteDC(hDest); ReleaseDC(hDesk, hSrce); bmp.Save(@"c:\temp\test.png"); bmp.Dispose(); } // P/Invoke declarations [DllImport("gdi32.dll")] static extern bool BitBlt(IntPtr hdcDest, int xDest, int yDest, int wDest, int hDest, IntPtr hdcSource, int xSrc, int ySrc, CopyPixelOperation rop); [DllImport("user32.dll")] static extern bool ReleaseDC(IntPtr hWnd, IntPtr hDc); [DllImport("gdi32.dll")] static extern IntPtr DeleteDC(IntPtr hDc); [DllImport("gdi32.dll")] static extern IntPtr DeleteObject(IntPtr hDc); [DllImport("gdi32.dll")] static extern IntPtr CreateCompatibleBitmap(IntPtr hdc, int nWidth, int nHeight); [DllImport("gdi32.dll")] static extern IntPtr CreateCompatibleDC(IntPtr hdc); [DllImport("gdi32.dll")] static extern IntPtr SelectObject(IntPtr hdc, IntPtr bmp); [DllImport("user32.dll")] public static extern IntPtr GetDesktopWindow(); [DllImport("user32.dll")] public static extern IntPtr GetWindowDC(IntPtr ptr); } }
Fwiw,Windows的更高版本提供了针对此错误的解决方法。不确定,我认为是Win7 SP1。如果 仅 传递CopyPixelOperation.CaptureBlt选项,则BitBlt()函数现在将执行所需的操作。但是,当然,该解决方法并未追溯应用到早期Windows版本,因此您不能真正依赖它。