如何在位图上绘制整个表单？

问题描述

我想在 TBitmap 对象上绘制包括标题栏和框架在内的整个表单。

I want to paint the whole form including its caption bar and frame on a TBitmap object.

GetFormImage 很酷，但是有两个问题：

GetFormImage is cool, but it has two problems:

• 它也不会绘制窗口框。


• 隐藏表单时不起作用。

有解决这些问题的想法吗？

Do you have any idea to workaround these problems?

推荐答案

访问非客户区的关键是函数，其他所有操作均像往常一样：

The key to accessing non-client area is GetWindowDC function, everything else is blitting as usual:

procedure TForm5.FormClick(Sender: TObject);
var
  Bitmap: TBitmap;
  DC: HDC;
  FileName: string;
begin
  Bitmap := TBitmap.Create;
  try
    Assert(HandleAllocated);
    DC := GetWindowDC(Handle);
    Win32Check(DC <> 0);

    Bitmap.SetSize(Width, Height);

    Win32Check(BitBlt(Bitmap.Canvas.Handle, 0, 0, Width, Height, DC, 0, 0, SRCCOPY));

    FileName := Name + '.' + GraphicExtension(TBitmap);
    Bitmap.SaveToFile(FileName);

    ShellExecute(HWND_DESKTOP, nil, PChar(FileName), nil, nil, SW_NORMAL);
  finally
    ReleaseDC(Handle, DC);
    Bitmap.Free;
  end;
end;

对于第二种隐藏（未绘制！）窗口-请参阅RRUZ的评论。

For the second case of hidden (not painted!) window - see a comment from RRUZ.

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