private class WebControlImage
{
internal static class NativeMethods
{
[StructLayout(LayoutKind.Sequential)]
public sealed class tagDVTARGETDEVICE
{
[MarshalAs(UnmanagedType.U4)]
public int tdSize;
[MarshalAs(UnmanagedType.U2)]
public short tdDriverNameOffset;
[MarshalAs(UnmanagedType.U2)]
public short tdDeviceNameOffset;
[MarshalAs(UnmanagedType.U2)]
public short tdPortNameOffset;
[MarshalAs(UnmanagedType.U2)]
public short tdExtDevmodeOffset;
}
[StructLayout(LayoutKind.Sequential)]
public class COMRECT
{
public int left;
public int top;
public int right;
public int bottom;
public COMRECT()
{
}
public COMRECT(Rectangle r)
{
this.left = r.X;
this.top = r.Y;
this.right = r.Right;
this.bottom = r.Bottom;
}
public COMRECT(int left, int top, int right, int bottom)
{
this.left = left;
this.top = top;
this.right = right;
this.bottom = bottom;
}
public static NativeMethods.COMRECT FromXYWH(int x, int y, int width, int height)
{
return new NativeMethods.COMRECT(x, y, x + width, y + height);
}
public override string ToString()
{
return string.Concat(new object[] { "Left = ", this.left, " Top ", this.top, " Right = ", this.right, " Bottom = ", this.bottom });
}
}
[StructLayout(LayoutKind.Sequential)]
public sealed class tagLOGPALETTE
{
[MarshalAs(UnmanagedType.U2)]
public short palVersion;
[MarshalAs(UnmanagedType.U2)]
public short palNumEntries;
}
}
public class Snapshot
{
///
/// ?煺?
///
/// Com 对象
/// 图象大小
///
public Task<Bitmap> TakeSnapshot(object pUnknown, Rectangle bmpRect)
{
return Task.Run(() =>
{
if (pUnknown == null)
return null;
//必须为com对象
if (!Marshal.IsComObject(pUnknown))
return null;
//IViewObject 接口
UnsafeNativeMethods.IViewObject ViewObject = null;
IntPtr pViewObject = IntPtr.Zero;
//内存图
Bitmap pPicture = new Bitmap(bmpRect.Width, bmpRect.Height);
Graphics hDrawDC = Graphics.FromImage(pPicture);
//获取接口
object hret = Marshal.QueryInterface(Marshal.GetIUnknownForObject(pUnknown),
ref UnsafeNativeMethods.IID_IViewObject, out pViewObject);
try
{
ViewObject = Marshal.GetTypedObjectForIUnknown(pViewObject, typeof(UnsafeNativeMethods.IViewObject)) as UnsafeNativeMethods.IViewObject;
//调用Draw方法
ViewObject.Draw((int)System.Runtime.InteropServices.ComTypes.DVASPECT.DVASPECT_CONTENT,
-1,
IntPtr.Zero,
null,
IntPtr.Zero,
hDrawDC.GetHdc(),
new NativeMethods.COMRECT(bmpRect),
null,
IntPtr.Zero,
0);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
throw ex;
}
//释放
hDrawDC.Dispose();
return pPicture;
});
}
[SuppressUnmanagedCodeSecurity]
internal static class UnsafeNativeMethods
{
public static Guid IID_IViewObject = new Guid("{0000010d-0000-0000-C000-000000000046}");
[ComImport, Guid("0000010d-0000-0000-C000-000000000046"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IViewObject
{
[PreserveSig]
int Draw([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] NativeMethods.tagDVTARGETDEVICE ptd, IntPtr hdcTargetDev, IntPtr hdcDraw, [In] NativeMethods.COMRECT lprcBounds, [In] NativeMethods.COMRECT lprcWBounds, IntPtr pfnContinue, [In] int dwContinue);
[PreserveSig]
int GetColorSet([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [In] NativeMethods.tagDVTARGETDEVICE ptd, IntPtr hicTargetDev, [Out] NativeMethods.tagLOGPALETTE ppColorSet);
[PreserveSig]
int Freeze([In, MarshalAs(UnmanagedType.U4)] int dwDrawAspect, int lindex, IntPtr pvAspect, [Out] IntPtr pdwFreeze);
[PreserveSig]
int Unfreeze([In, MarshalAs(UnmanagedType.U4)] int dwFreeze);
void SetAdvise([In, MarshalAs(UnmanagedType.U4)] int aspects, [In, MarshalAs(UnmanagedType.U4)] int advf, [In, MarshalAs(UnmanagedType.Interface)] System.Runtime.InteropServices.ComTypes.IAdviseSink pAdvSink);
void GetAdvise([In, Out, MarshalAs(UnmanagedType.LPArray)] int[] paspects, [In, Out, MarshalAs(UnmanagedType.LPArray)] int[] advf, [In, Out, MarshalAs(UnmanagedType.LPArray)] System.Runtime.InteropServices.ComTypes.IAdviseSink[] pAdvSink);
}
}
}
}
