Library to display an image (JPG/GIF/BMP) in 300 lines/8K of code

#include <windows.h>
#include <ocidl.h>
#include <olectl.h>

typedef struct tagImgInfo {
	IPicture *Ipic;
	SIZE sizeInHiMetric;
	SIZE sizeInPix;
	char *Path;
} IMG_INFO;

static IMG_INFO ImageInfo;

void *OpenGraphic(char *name)
{
	IPicture *Ipic = NULL;
	SIZE sizeInHiMetric,sizeInPix;
	const int HIMETRIC_PER_INCH = 2540;
	HDC hDCScreen = GetDC(NULL);
	HRESULT hr;
	int nPixelsPerInchX = GetDeviceCaps(hDCScreen, LOGPIXELSX);
	int nPixelsPerInchY = GetDeviceCaps(hDCScreen, LOGPIXELSY);
	unsigned short OlePathName[512];

	ReleaseDC(NULL,hDCScreen);
	mbstowcs(OlePathName,name,strlen(name)+1);
	hr = OleLoadPicturePath(OlePathName,
									  NULL,
									  0,
									  0,
									  &IID_IPicture,
									  (void *)(&Ipic));
	if (hr)
		return 0;
	if (Ipic) {
		// get width and height of picture
		hr = Ipic->lpVtbl->get_Width(Ipic,&sizeInHiMetric.cx);
		if (!SUCCEEDED(hr))
			goto err;
		Ipic->lpVtbl->get_Height(Ipic,&sizeInHiMetric.cy);
		if (!SUCCEEDED(hr))
			goto err;

		// convert himetric to pixels
		sizeInPix.cx = (nPixelsPerInchX * sizeInHiMetric.cx +
						  HIMETRIC_PER_INCH / 2) / HIMETRIC_PER_INCH;
		sizeInPix.cy = (nPixelsPerInchY * sizeInHiMetric.cy +
						  HIMETRIC_PER_INCH / 2) / HIMETRIC_PER_INCH;
		ImageInfo.sizeInPix = sizeInPix;
		ImageInfo.sizeInHiMetric = sizeInHiMetric;
		ImageInfo.Ipic = Ipic;
		ImageInfo.Path = name;
		return Ipic;

	}
err:
	return 0;
}
void DisplayGraphic(HWND hwnd,HDC pDC)
{
	IPicture *Ipic = ImageInfo.Ipic;
	DWORD dwAttr = 0;
	HBITMAP Bmp,BmpOld;
	RECT rc;
	HRESULT hr;
	HPALETTE pPalMemOld;

	if (Ipic != NULL)
	{
		// get palette
		HPALETTE hPal = NULL,hPalOld=NULL,hPalMemOld=NULL;
		hr = Ipic->lpVtbl->get_hPal(Ipic,&hPal);

		if (!SUCCEEDED(hr))
			return;
		if (hPal != NULL)
		{
			hPalOld = SelectPalette(pDC,hPal,FALSE);
			RealizePalette(pDC);
		}

		// Fit the image to the size of the client area. Change this
		// For more sophisticated scaling
		GetClientRect(hwnd,&rc);
		// transparent?
		if (SUCCEEDED(Ipic->lpVtbl->get_Attributes(Ipic,&dwAttr)) ||
			(dwAttr & PICTURE_TRANSPARENT))
		{
			// use an off-screen DC to prevent flickering
			HDC MemDC = CreateCompatibleDC(pDC);
			Bmp = CreateCompatibleBitmap(pDC,ImageInfo.sizeInPix.cx,ImageInfo.sizeInPix.cy);

			BmpOld = SelectObject(MemDC,Bmp);
			pPalMemOld = NULL;
			if (hPal != NULL)
			{
				hPalMemOld = SelectPalette(MemDC,hPal, FALSE);
				RealizePalette(MemDC);
			}
/* Use this to show the left corner
			rc.left = rc.top = 0;
			rc.right = ImageInfo.sizeInPix.cx;
		    rc.bottom = ImageInfo.sizeInPix.cy;
*/
			// display picture using IPicture::Render
			hr = Ipic->lpVtbl->Render(Ipic,MemDC,
												0,
												0,
												rc.right,
												rc.bottom,
												0,
												ImageInfo.sizeInHiMetric.cy,
												ImageInfo.sizeInHiMetric.cx,
												-ImageInfo.sizeInHiMetric.cy,
												&rc);

			BitBlt(pDC,0, 0, ImageInfo.sizeInPix.cx, ImageInfo.sizeInPix.cy,
							   MemDC, 0, 0, SRCCOPY);

			SelectObject(MemDC,BmpOld);

			if (pPalMemOld)	SelectPalette(MemDC,pPalMemOld, FALSE);
			DeleteObject(Bmp);
			DeleteDC(MemDC);

		}
		else
		{
			// display picture using IPicture::Render
			Ipic->lpVtbl->Render(Ipic,pDC,
										 0,
										 0,
										 rc.right,
										 rc.bottom,
										 0,
										 ImageInfo.sizeInHiMetric.cy,
										 ImageInfo.sizeInHiMetric.cx,
										 -ImageInfo.sizeInHiMetric.cy,
										 &rc);
		}

		if (hPalOld != NULL) SelectPalette(pDC,hPalOld, FALSE);
		if (hPal)	DeleteObject(hPal);
	}
}

void CloseImage(void *Ipict)
{
	IPicture *ip = (IPicture *)Ipict;

	if (ip == NULL)
		ip = ImageInfo.Ipic;
	if (ip == NULL)
		return;
	ip->lpVtbl->Release(ip);
	memset(&ImageInfo,0,sizeof(ImageInfo));
}