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C-捕获鼠标光标图像

screenshot icons cursor mouse c#

namenlos · 技术社区 · 16 年前

背景

我正在编写屏幕捕获应用程序
我的代码基于此项目: http://www.codeproject.com/KB/cs/DesktopCaptureWithMouse.aspx?display=Print
注意,代码也捕获鼠标光标(这对我来说是可取的)

我的问题

当鼠标光标是普通指针或手图标时,代码工作正常-鼠标在屏幕截图上呈现正确
然而,当鼠标光标被改变为插入点(“i-束”光标)时,例如在记事本中键入代码,那么代码就不起作用了,结果是,我得到光标的模糊图像,就像它的半透明(灰色)版本,而不是空白的和白色的。

我的问题

当图像是这些“i-beam”类型的图像之一时,如何捕获鼠标光标图像
注意:如果你点击原始文章,就会有人提出建议——它不起作用。

来源

这是原文。

    static Bitmap CaptureCursor(ref int x, ref int y)
    {
        Bitmap bmp;
        IntPtr hicon;
        Win32Stuff.CURSORINFO ci = new Win32Stuff.CURSORINFO();
        Win32Stuff.ICONINFO icInfo;
        ci.cbSize = Marshal.SizeOf(ci);
        if (Win32Stuff.GetCursorInfo(out ci))
        {
            if (ci.flags == Win32Stuff.CURSOR_SHOWING)
            {
                hicon = Win32Stuff.CopyIcon(ci.hCursor);
                if (Win32Stuff.GetIconInfo(hicon, out icInfo))
                {
                    x = ci.ptScreenPos.x - ((int)icInfo.xHotspot);
                    y = ci.ptScreenPos.y - ((int)icInfo.yHotspot);

                    Icon ic = Icon.FromHandle(hicon);
                    bmp = ic.ToBitmap(); 
                    return bmp;
                }
            }
        }

        return null;
    }

6 回复 | 直到 8 年前

caesay 9 年前

虽然我不能确切地解释为什么会发生这种情况,但我想我可以展示如何绕过它。

iconinfo结构包含两个成员hbmmask和hbmcolor,分别包含光标的掩码和颜色位图(请参见msdn页 ICONINFO 官方文件)。

为默认光标调用getICONINFO()时,ICONINFO结构包含有效的遮罩和颜色位图,如下所示(注意:已添加红色边框以清楚显示图像边界):

默认光标蒙板位图 default cursor mask bitmap image http://img4.imageshack.us/img4/1108/arrowmask.png

默认光标颜色位图 default cursor color bitmap image http://img191.imageshack.us/img191/7680/arrowcolor.png

当Windows绘制默认光标时,首先使用和光栅操作应用遮罩位图,然后使用XOR光栅操作应用颜色位图。这将导致不透明的光标和透明的背景。

但是,当您为i-beam光标调用geticoninfo()时,iconinfo结构只包含有效的遮罩位图,而不包含颜色位图,如下所示(注意:再次添加红色边框以清楚地显示图像边界):

工字梁光标蒙板位图 ibeam cursor mask bitmap image http://img14.imageshack.us/img14/6025/ibeammask.png

根据iconinfo文档,i-beam光标是单色光标。遮罩位图的上半部分是和遮罩,而遮罩位图的下半部分是XOR位图。当Windows绘制工字梁光标时,该位图的上半部分首先通过“和光栅”操作绘制在桌面上。然后,使用XOR光栅操作在顶部绘制位图的下半部分。在屏幕上,光标将显示为其后面内容的倒数。

其中之一 comments 对于您链接的原始文章,提到了这一点。在桌面上,由于光栅操作应用于桌面内容,因此光标将正确显示。但是,当图像不在背景上绘制时(如在已发布的代码中),Windows执行的光栅操作会导致图像褪色。

也就是说,这个更新的capturecursor()方法将处理彩色和单色光标,当光标为单色时提供纯黑色光标图像。

static Bitmap CaptureCursor(ref int x, ref int y)
{
  Win32Stuff.CURSORINFO cursorInfo = new Win32Stuff.CURSORINFO();
  cursorInfo.cbSize = Marshal.SizeOf(cursorInfo);
  if (!Win32Stuff.GetCursorInfo(out cursorInfo))
    return null;

  if (cursorInfo.flags != Win32Stuff.CURSOR_SHOWING)
    return null;

  IntPtr hicon = Win32Stuff.CopyIcon(cursorInfo.hCursor);
  if (hicon == IntPtr.Zero)
    return null;

  Win32Stuff.ICONINFO iconInfo;
  if (!Win32Stuff.GetIconInfo(hicon, out iconInfo))
    return null;

  x = cursorInfo.ptScreenPos.x - ((int)iconInfo.xHotspot);
  y = cursorInfo.ptScreenPos.y - ((int)iconInfo.yHotspot);

  using (Bitmap maskBitmap = Bitmap.FromHbitmap(iconInfo.hbmMask))
  {
    // Is this a monochrome cursor?
    if (maskBitmap.Height == maskBitmap.Width * 2)
    {
      Bitmap resultBitmap = new Bitmap(maskBitmap.Width, maskBitmap.Width);

      Graphics desktopGraphics = Graphics.FromHwnd(Win32Stuff.GetDesktopWindow());
      IntPtr desktopHdc = desktopGraphics.GetHdc();

      IntPtr maskHdc = Win32Stuff.CreateCompatibleDC(desktopHdc);
      IntPtr oldPtr = Win32Stuff.SelectObject(maskHdc, maskBitmap.GetHbitmap());

      using (Graphics resultGraphics = Graphics.FromImage(resultBitmap))
      {
        IntPtr resultHdc = resultGraphics.GetHdc();

        // These two operation will result in a black cursor over a white background.
        // Later in the code, a call to MakeTransparent() will get rid of the white background.
        Win32Stuff.BitBlt(resultHdc, 0, 0, 32, 32, maskHdc, 0, 32, Win32Stuff.TernaryRasterOperations.SRCCOPY);
        Win32Stuff.BitBlt(resultHdc, 0, 0, 32, 32, maskHdc, 0, 0, Win32Stuff.TernaryRasterOperations.SRCINVERT);

        resultGraphics.ReleaseHdc(resultHdc);
      }

      IntPtr newPtr = Win32Stuff.SelectObject(maskHdc, oldPtr);
      Win32Stuff.DeleteObject(newPtr);
      Win32Stuff.DeleteDC(maskHdc);
      desktopGraphics.ReleaseHdc(desktopHdc);

      // Remove the white background from the BitBlt calls,
      // resulting in a black cursor over a transparent background.
      resultBitmap.MakeTransparent(Color.White);
      return resultBitmap;
    }
  }

  Icon icon = Icon.FromHandle(hicon);
  return icon.ToBitmap();
}

代码有一些问题,可能是或不是问题。

检查单色光标只需测试高度是否是宽度的两倍。虽然这看起来很合乎逻辑,但ICONINFO文档并不要求仅定义单色光标。
可能有更好的方法来呈现我使用的方法调用的bitblt()-bitblt()-makeTransparent()组合的光标。

Dimitar 13 年前

[StructLayout(LayoutKind.Sequential)]
struct CURSORINFO
{
    public Int32 cbSize;
    public Int32 flags;
    public IntPtr hCursor;
    public POINTAPI ptScreenPos;
}

[StructLayout(LayoutKind.Sequential)]
struct POINTAPI
{
    public int x;
    public int y;
}

[DllImport("user32.dll")]
static extern bool GetCursorInfo(out CURSORINFO pci);

[DllImport("user32.dll")]
static extern bool DrawIcon(IntPtr hDC, int X, int Y, IntPtr hIcon);

const Int32 CURSOR_SHOWING = 0x00000001;

public static Bitmap CaptureScreen(bool CaptureMouse)
{
    Bitmap result = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format24bppRgb);

    try
    {
        using (Graphics g = Graphics.FromImage(result))
        {
            g.CopyFromScreen(0, 0, 0, 0, Screen.PrimaryScreen.Bounds.Size, CopyPixelOperation.SourceCopy);

            if (CaptureMouse)
            {
                CURSORINFO pci;
                pci.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(typeof(CURSORINFO));

                if (GetCursorInfo(out pci))
                {
                    if (pci.flags == CURSOR_SHOWING)
                    {
                        DrawIcon(g.GetHdc(), pci.ptScreenPos.x, pci.ptScreenPos.y, pci.hCursor);
                        g.ReleaseHdc();
                    }
                }
            }
        }
    }
    catch
    {
        result = null;
    }

    return result;
}

johv Chris 12 年前

下面是Dimitar的一个修改版本的响应(使用drawiconex),它在多个屏幕上对我有效:

public class ScreenCapturePInvoke
{
    [StructLayout(LayoutKind.Sequential)]
    private struct CURSORINFO
    {
        public Int32 cbSize;
        public Int32 flags;
        public IntPtr hCursor;
        public POINTAPI ptScreenPos;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct POINTAPI
    {
        public int x;
        public int y;
    }

    [DllImport("user32.dll")]
    private static extern bool GetCursorInfo(out CURSORINFO pci);

    [DllImport("user32.dll", SetLastError = true)]
    static extern bool DrawIconEx(IntPtr hdc, int xLeft, int yTop, IntPtr hIcon, int cxWidth, int cyHeight, int istepIfAniCur, IntPtr hbrFlickerFreeDraw, int diFlags);

    private const Int32 CURSOR_SHOWING = 0x0001;
    private const Int32 DI_NORMAL = 0x0003;

    public static Bitmap CaptureFullScreen(bool captureMouse)
    {
        var allBounds = Screen.AllScreens.Select(s => s.Bounds).ToArray();
        Rectangle bounds = Rectangle.FromLTRB(allBounds.Min(b => b.Left), allBounds.Min(b => b.Top), allBounds.Max(b => b.Right), allBounds.Max(b => b.Bottom));

        var bitmap = CaptureScreen(bounds, captureMouse);
        return bitmap;
    }

    public static Bitmap CapturePrimaryScreen(bool captureMouse)
    {
        Rectangle bounds = Screen.PrimaryScreen.Bounds;

        var bitmap = CaptureScreen(bounds, captureMouse);
        return bitmap;
    }

    public static Bitmap CaptureScreen(Rectangle bounds, bool captureMouse)
    {
        Bitmap result = new Bitmap(bounds.Width, bounds.Height);

        try
        {
            using (Graphics g = Graphics.FromImage(result))
            {
                g.CopyFromScreen(bounds.Location, Point.Empty, bounds.Size);

                if (captureMouse)
                {
                    CURSORINFO pci;
                    pci.cbSize = Marshal.SizeOf(typeof (CURSORINFO));

                    if (GetCursorInfo(out pci))
                    {
                        if (pci.flags == CURSOR_SHOWING)
                        {
                            var hdc = g.GetHdc();
                            DrawIconEx(hdc, pci.ptScreenPos.x-bounds.X, pci.ptScreenPos.y-bounds.Y, pci.hCursor, 0, 0, 0, IntPtr.Zero, DI_NORMAL);
                            g.ReleaseHdc();
                        }
                    }
                }
            }
        }
        catch
        {
            result = null;
        }

        return result;
    }
}

nvuono 16 年前

您对半透明的“灰色”i-beam光标的描述让我怀疑您是否遇到了图像缩放或光标位置错误的问题。

在那个网站上发布的一个人提供了一个(断开的)链接,指向一个具有特殊行为的报告,我跟踪到: http://www.efg2.com/Lab/Graphics/CursorOverlay.htm

该页面上的示例不在C中,但代码项目解决方案的作者可能正在做类似的事情,我知道在很多场合使用图形对象时,我自己都搞砸了缩放比例:

在任何ImageMousedown事件中, 图像已加载,CusOrbitmap是在使用canvas.draw方法进行位图。注意一些坐标调整 (重新缩放)是必要的,以防位图被拉伸以适应 TImage。

Daniel 8 年前

基于其他答案,我制作了一个没有所有Windows API材料的版本(对于单色部分),因为解决方案不适用于所有单色光标。我通过组合两个遮罩部分从遮罩创建光标。

我的解决方案:

Bitmap CaptureCursor(ref Point position)
{
   CURSORINFO cursorInfo = new CURSORINFO();
   cursorInfo.cbSize = Marshal.SizeOf(cursorInfo);
   if (!GetCursorInfo(out cursorInfo))
      return null;

   if (cursorInfo.flags != CURSOR_SHOWING)
      return null;

   IntPtr hicon = CopyIcon(cursorInfo.hCursor);
   if (hicon == IntPtr.Zero)
      return null;

   ICONINFO iconInfo;
   if (!GetIconInfo(hicon, out iconInfo))
      return null;

   position.X = cursorInfo.ptScreenPos.x - iconInfo.xHotspot;
   position.Y = cursorInfo.ptScreenPos.y - iconInfo.yHotspot;

   using (Bitmap maskBitmap = Bitmap.FromHbitmap(iconInfo.hbmMask))
   {
      // check for monochrome cursor
      if (maskBitmap.Height == maskBitmap.Width * 2)
      {
         Bitmap cursor = new Bitmap(32, 32, PixelFormat.Format32bppArgb);
         Color BLACK = Color.FromArgb(255, 0, 0, 0); //cannot compare Color.Black because of different names
         Color WHITE = Color.FromArgb(255, 255, 255, 255); //cannot compare Color.White because of different names
         for (int y = 0; y < 32; y++)
         {
            for (int x = 0; x < 32; x++)
            {
               Color maskPixel = maskBitmap.GetPixel(x, y);
               Color cursorPixel = maskBitmap.GetPixel(x, y + 32);
               if (maskPixel == WHITE && cursorPixel == BLACK)
               {
                  cursor.SetPixel(x, y, Color.Transparent);
               }
               else if (maskPixel == BLACK)
               {
                  cursor.SetPixel(x, y, cursorPixel);
               }
               else
               {
                  cursor.SetPixel(x, y, cursorPixel == BLACK ? WHITE : BLACK);
               }
            }
         }
         return cursor;
      }
   }

   Icon icon = Icon.FromHandle(hicon);
   return icon.ToBitmap();
}

Vladimír Adamovský 8 年前

这是修补版本,包含此页面上显示的所有错误修复:

public static Bitmap CaptureImageCursor(ref Point point)
{
    try
    {
        var cursorInfo = new CursorInfo();
        cursorInfo.cbSize = Marshal.SizeOf(cursorInfo);

        if (!GetCursorInfo(out cursorInfo))
            return null;

        if (cursorInfo.flags != CursorShowing)
            return null;

        var hicon = CopyIcon(cursorInfo.hCursor);
        if (hicon == IntPtr.Zero)
            return null;

        Iconinfo iconInfo;
        if (!GetIconInfo(hicon, out iconInfo))
        {
            DestroyIcon(hicon);
            return null;
        }

        point.X = cursorInfo.ptScreenPos.X - iconInfo.xHotspot;
        point.Y = cursorInfo.ptScreenPos.Y - iconInfo.yHotspot;

        using (var maskBitmap = Image.FromHbitmap(iconInfo.hbmMask))
        {
            //Is this a monochrome cursor?  
            if (maskBitmap.Height == maskBitmap.Width * 2 && iconInfo.hbmColor == IntPtr.Zero)
            {
                var final = new Bitmap(maskBitmap.Width, maskBitmap.Width);
                var hDesktop = GetDesktopWindow();
                var dcDesktop = GetWindowDC(hDesktop);

                using (var resultGraphics = Graphics.FromImage(final))
                {
                    var resultHdc = resultGraphics.GetHdc();

                    BitBlt(resultHdc, 0, 0, final.Width, final.Height, dcDesktop, (int)point.X + 3, (int)point.Y + 3, CopyPixelOperation.SourceCopy);
                    DrawIconEx(resultHdc, 0, 0, cursorInfo.hCursor, 0, 0, 0, IntPtr.Zero, 0x0003);

                    //TODO: I have to try removing the background of this cursor capture.
                    //Native.BitBlt(resultHdc, 0, 0, final.Width, final.Height, dcDesktop, (int)point.X + 3, (int)point.Y + 3, Native.CopyPixelOperation.SourceErase);

                    resultGraphics.ReleaseHdc(resultHdc);
                    ReleaseDC(hDesktop, dcDesktop);
                }

                DeleteObject(iconInfo.hbmMask);
                DeleteDC(dcDesktop);
                DestroyIcon(hicon);

                return final;
            }

            DeleteObject(iconInfo.hbmColor);
            DeleteObject(iconInfo.hbmMask);
            DestroyIcon(hicon);
        }

        var icon = Icon.FromHandle(hicon);
        return icon.ToBitmap();
    }
    catch (Exception ex)
    {
        //You should catch exception with your method here.
        //LogWriter.Log(ex, "Impossible to get the cursor.");
    }

    return null;
}

此版本适用于:

I-光束光标。
黑色游标。
正常游标。
反向光标。

见工作,这里: https://github.com/NickeManarin/ScreenToGif/blob/master/ScreenToGif/Util/Native.cs#L991