#Stretchblt copyimage how to#
#Stretchblt copyimage code#
#Stretchblt copyimage windows#

Std::basic_string ss(buff.begin(),buff.begin() + nc) Sres = StretchBlt(hdc,dct.left,dct.top,dct.right,dct.bottom,mdc,rct.left,rct.top,rct.right,rct.bottom,SRCCOPY) ĭWORD nc(FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, Sres = DPtoLP(mdc,reinterpret_cast(&dct),2) Sres = Rectangle(mdc,rct.left,rct.top,rct.right,rct.bottom) Sres = DPtoLP(mdc,reinterpret_cast(&rct),2) Int hdcaps(GetDeviceCaps(hdc,RASTERCAPS)) Int mdcaps(GetDeviceCaps(mdc,RASTERCAPS)) Now the longer version with error checking at every call: case WM_PAINT: StretchBlt(hdc,dct.left,dct.top,dct.right,dct.bottom,mdc,rct.left,rct.top,rct.right,rct.bottom,SRCCOPY)

Rectangle(mdc,rct.left,rct.top,rct.right,rct.bottom) HBRUSH hBrush = CreateSolidBrush(RGB(255,255,255)) HBITMAP mbm(CreateCompatibleBitmap(pdc,pwd,pht)) Pdlg.Flags = PD_RETURNDEFAULT | PD_RETURNDC Std::fill_n(reinterpret_cast(&pdlg),sizeof(PRINTDLG),static_cast(0)) If (ps.rcPaint.right & ps.rcPaint.bottom) Both fail doing the StretchBlt and, as the second longer version which shows the GetLastError call shows, GetlastError returns 0. Either of these two versions which can be put in a main window's WM_PAINT handler, since they do exactly the same thing.

#Stretchblt copyimage code#

Here is a better example of code illustrating this problem. It becomes hard figuring out what is wrong in that case. The issue is: Why would StretchBlt ever return FALSE and GetLastError then return 0. The StretchBlt fails but all the other device context actions succeed. «_Superman_» Microsoft MVP (Visual C++) It looks something like this: - case WM_PAINT: - The m_hdcSrc device context is created earlier in the dialog object and is a memory DC.

#Stretchblt copyimage windows#

I am testing this on Windows Vista 64 Ultimate in a 32-bit application.Ĭould you post how StretchBlt is called including its parameters. Any ideas or help tracking this GDI failure down would be appreciated. It is possible the rectangular co-ordinates for my source and destination DCs are 'incorrect' in the StretchBlt call, but I would expect a GetLastError code if that were the situation. If I attempt other device context operations on my destination context, such as FillRect, Rectangle, TextOut etc., they all succeed.

#Stretchblt copyimage how to#

I am baffled on how to determine why the StretchBlt fails as it is keeping a window from displaying data. I checked the capabilities of both the source and destination device contexts using GetDeviceCaps and RASTERCAPS and had supported for the source and destination devices: RC_BITBLT RC_BITMAP64 RC_DI_BITMAP RC_DIBTODEV RC_STRETCHBLT RC_STRETCHDIB while the destination device also had RC_FLOODFILL supported. ' So I immediately call GetLastError only to be returned 0. Windows NT/2000/XP: To get extended error information, call GetLastError.

If the function fails, the return value is zero. According to the documentation for StretchBlt: 'StretchBlt If the function succeeds, the return value is nonzero. The source DC is a memory DC and the destination DC is my WM_PAINT handler DC accessed via the BeginPaint function.

In my WM_PAINT handler code in a dialog I call StretchBlt and it fails with a return of FALSE.