hi,

for quiet some time i am occupied by this little assignment:

Take a screenshot, shrink it (while preserving the aspect ration) and save it to disk.

my code:

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes	ImageCodecInfo* pImageCodecInfo = NULL;	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure	pImageCodecInfo = (ImageCodecInfo*)(GlobalAlloc(0,size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure	GetImageEncoders(num, size, pImageCodecInfo);	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			GlobalFree(pImageCodecInfo);
			return j;  // Success
		}    
	}	GlobalFree(pImageCodecInfo);
	return 0;
}int main()
{
	ULONG_PTR m_gdiplusToken;
	Gdiplus::GdiplusStartupInput gdiplusStartupInput;
	Gdiplus::GdiplusStartup(&m_gdiplusToken, &gdiplusStartupInput, NULL);
	Bitmap* bm = new Bitmap(1450,1050,PixelFormat32bppARGB);//create an empty image	HDC scrn = GetDC(0);//take screenshot
	Graphics gr(scrn);//assign it to a graphics object	gr.DrawImage(bm,100,100,1450,1050);//shrink it to 100x100	CLSID clsid;
	GetEncoderClsid(L"image/jpeg", &clsid);//get jpg encoder	bm->Save(L"D:\\wtf.jpg",&clsid);//save image	return 0;
}

obviously i am not the greatest gdi+ expert around...

but i cant see why this code just fails without any error (image is just not created....)

Edited April 3, 201114 yr by deepzero

Looks like you forgot to fill gdiplusStartupInput, at least .GdiplusVersion must be 1