internal static Bitmap MakeSnapshot(IntPtr parentWinHandle,
bool isClientWnd, Win32Api.WindowShowStyle nCmdShow)
{
if (parentWinHandle == IntPtr.Zero || !Win32Api.IsWindow(parentWinHandle) ||
!Win32Api.IsWindowVisible(parentWinHandle))
{
return(null);
}
if (Win32Api.IsIconic(parentWinHandle))
{
Win32Api.ShowWindow(parentWinHandle, nCmdShow);//show it
}
if (!Win32Api.SetForegroundWindow(parentWinHandle))
{
return(null);//can't bring it to front
}
Win32Api.ShowWindow(parentWinHandle, Win32Api.WindowShowStyle.ShowMinimized);
Win32Api.ShowWindow(parentWinHandle, Win32Api.WindowShowStyle.Restore);
var appWndHandle = parentWinHandle;
System.Threading.Thread.Sleep(1000);//give it some time to redraw
RECT appRect;
bool res = Win32Api.GetWindowRect
(appWndHandle, out appRect);
if (!res || appRect.Height == 0 || appRect.Width == 0)
{
return(null);//some hidden window
}
// calculate the app rectangle
//Intersect with the Desktop rectangle and get what's visible
IntPtr DesktopHandle = Win32Api.GetDesktopWindow();
RECT desktopRect;
Win32Api.GetWindowRect(DesktopHandle, out desktopRect);
RECT visibleRect;
if (!Win32Api.IntersectRect
(out visibleRect, ref desktopRect, ref appRect))
{
visibleRect = appRect;
}
if (Win32Api.IsRectEmpty(ref visibleRect))
{
return(null);
}
int Width = visibleRect.Width;
int Height = visibleRect.Height;
IntPtr hdcTo = IntPtr.Zero;
IntPtr hdcFrom = IntPtr.Zero;
IntPtr hBitmap = IntPtr.Zero;
try
{
Bitmap result = null;
// get device context of the window...
hdcFrom = Win32Api.GetDC(appWndHandle);
// create dc that we can draw to...
hdcTo = Win32Api.CreateCompatibleDC(hdcFrom);
hBitmap = Win32Api.CreateCompatibleBitmap(hdcFrom, Width, Height);
// validate
if (hBitmap != IntPtr.Zero)
{
// adjust and copy
int x = appRect.Left < 0 ? -appRect.Left : 0;
int y = appRect.Top < 0 ? -appRect.Top : 0;
IntPtr hLocalBitmap = Win32Api.SelectObject(hdcTo, hBitmap);
Win32Api.BitBlt(hdcTo, 0, 0, Width, Height,
hdcFrom, 0, 0, Win32Api.SRCCOPY);
Win32Api.SelectObject(hdcTo, hLocalBitmap);
// create bitmap for window image...
using (var screenShot = Image.FromHbitmap(hBitmap))
{
// For some reason, the area that was reserved for the screenshot is bigger than the actual
// result. We remove the black borders to the right and bottom here
result = CropBitmap(screenShot);
}
}
return(result);
}
finally
{
// release the unmanaged resources
if (hdcFrom != IntPtr.Zero)
{
Win32Api.ReleaseDC(appWndHandle, hdcFrom);
}
if (hdcTo != IntPtr.Zero)
{
Win32Api.DeleteDC(hdcTo);
}
if (hBitmap != IntPtr.Zero)
{
Win32Api.DeleteObject(hBitmap);
}
}
}
/// <summary>
/// Erzeugt einen Screenshot dieses Fensters.
/// </summary>
/// <param name="isClientWnd">Handelt es sich um das Handle eines Client-Fensters oder nícht.</param>
/// <param name="nCmdShow">Der WindowShowStyle.</param>
/// <param name="timeForRedrawing">Die Zeit, die gewartet werden soll, bis der Screenshot gemacht wird.</param>
/// <returns>Der Screenshot oder <see langword="null" />, wenn nicht ermittelbar.</returns>
public Bitmap MakeScreenshot(bool isClientWnd = false,
Win32Api.WindowShowStyle nCmdShow = Win32Api.WindowShowStyle.Restore,
TimeSpan?timeForRedrawing = null)
{
var appWndHandle = this.HWnd;
if (appWndHandle == IntPtr.Zero ||
!Win32Api.IsWindow(appWndHandle) ||
!Win32Api.IsWindowVisible(appWndHandle))
{
return(null);
}
if (Win32Api.IsIconic(appWndHandle))
{
Win32Api.ShowWindow(appWndHandle, nCmdShow); // show it
}
if (!Win32Api.SetForegroundWindow(appWndHandle))
{
return(null); // can't bring it to front
}
if (timeForRedrawing.HasValue)
{
// give it some time to redraw
Thread.Sleep(timeForRedrawing.Value);
}
RECT appRect;
var res = isClientWnd ? Win32Api.GetClientRect(appWndHandle, out appRect) : Win32Api.GetWindowRect(appWndHandle, out appRect);
if (!res ||
appRect.Height == 0 ||
appRect.Width == 0)
{
return(null); // some hidden window
}
if (isClientWnd)
{
var lt = new Point(appRect.Left, appRect.Top);
var rb = new Point(appRect.Right, appRect.Bottom);
Win32Api.ClientToScreen(appWndHandle, ref lt);
Win32Api.ClientToScreen(appWndHandle, ref rb);
appRect.Left = lt.X;
appRect.Top = lt.Y;
appRect.Right = rb.X;
appRect.Bottom = rb.Y;
}
// intersect with the Desktop rectangle and get what's visible
var desktopHandle = Win32Api.GetDesktopWindow();
RECT desktopRect;
Win32Api.GetWindowRect(desktopHandle, out desktopRect);
RECT visibleRect;
if (!Win32Api.IntersectRect(out visibleRect, ref desktopRect, ref appRect))
{
visibleRect = appRect;
}
if (Win32Api.IsRectEmpty(ref visibleRect))
{
return(null);
}
var width = visibleRect.Width;
var height = visibleRect.Height;
var hdcTo = IntPtr.Zero;
var hdcFrom = IntPtr.Zero;
var hBitmap = IntPtr.Zero;
try
{
Bitmap clsRet = null;
// get device context of the window...
hdcFrom = isClientWnd ? Win32Api.GetDC(appWndHandle) : Win32Api.GetWindowDC(appWndHandle);
// create dc that we can draw to...
hdcTo = Win32Api.CreateCompatibleDC(hdcFrom);
hBitmap = Win32Api.CreateCompatibleBitmap(hdcFrom, width, height);
// validate...
if (hBitmap != IntPtr.Zero)
{
// copy...
var x = appRect.Left < 0 ? -appRect.Left : 0;
var y = appRect.Top < 0 ? -appRect.Top : 0;
var hLocalBitmap = Win32Api.SelectObject(hdcTo, hBitmap);
Win32Api.BitBlt(hdcTo, 0, 0, width, height, hdcFrom, x, y, Win32Api.SRCCOPY);
Win32Api.SelectObject(hdcTo, hLocalBitmap);
// create bitmap for window image...
clsRet = System.Drawing.Image.FromHbitmap(hBitmap);
}
return(clsRet);
}
finally
{
// release...
if (hdcFrom != IntPtr.Zero)
{
Win32Api.ReleaseDC(appWndHandle, hdcFrom);
}
if (hdcTo != IntPtr.Zero)
{
Win32Api.DeleteDC(hdcTo);
}
if (hBitmap != IntPtr.Zero)
{
Win32Api.DeleteObject(hBitmap);
}
}
}
