Bmp to JPG

[llp00na]

Does any one know a routine/ method to change an image from Bmp to a JPG?

Thanks

[golanshahar]

You can use Image Class of GDI+.

Cheers

[cilu]

Or cxImage, but this might be a library too big for this task only.

[carl666]

You don't need anything.
Just use Win32 SHC api , which convert any graphic format

[VladimirF]

You don't need anything.
Just use Win32 SHC api , which convert any graphic format

Hi Carl,
In this and few other posts you are mentioning some mysterious native Win32 API to work with JPEG, PNG, etc.
Would you be so kind to name some of these API for the benefit of those of us who is unfamiliar with the subject?
Thank you!

[Owyn]

+ what SHC api?

[fransn]

You could use this COM dll which has a very easy to use interface to convert bitmaps to jpegs.
You need to rename imagehandler.zip to imagehandler.cab and then you can extract the contained dll.

[hoxsiew]

There's the CImage class that can do this too (since at least VS2003 IIRC).

[CBasicNet]

Here is the GDI+ code using the Image class to do it.

#include <GdiPlus.h>

#pragma comment(lib, "gdiplus")

void foo()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	{
		Image* pImage = Image::FromFile(L"D:\\abc.bmp", true);

		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		pImage->Save(L"D:\\abc.jpg", &clsid);

		delete pImage;
	}
	GdiplusShutdown(gdiplusToken);
}

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*)(malloc(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;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return -1;  // Failure
}