Loading images with an undocumented API in PPC 2002

Introduction

Loading images under windows can always be a painful process, especially if the image formats are like JPEG, GIF or PNG. There's always the Imgdecmp library, that does a good job, but its also a bit of a bother with the documentation being so thin and all that. The other day I was trying to load a bitmap from my device using LoadImage, but somehow I kept getting the dreaded "The handle is invalid" error. So I did a search on the MFC code that ships with the PPC SDK in hope of finding a piece of code that will help me solve the puzzle. 

One thing led to another. I suddenly came across HBITMAP SHLoadImageFile(LPCTSTR pszFileName) in aygshell.h. Bingo! I had suddenly uncovered an undocumented API! No trace of it in MSDN, a search in Google produced nothing!! Since then, I've tried this API with gif's and bmp's also and I guess it will work fine for jpeg's and png's too. Here's a code sample...

// assuming code is in the OnDraw method of a view....

CBitmap bitmap;

// Attach the bitmap object to the HBITMAP returned by SHLoadImageFile
bitmap.Attach(SHLoadImageFile(_T("/My Documents/mcdonalds.gif")));

BITMAP bmpInfo;
bitmap.GetBitmap(&bmpInfo);

CDC bitmapDC;
bitmapDC.CreateCompatibleDC(pDC);
CBitmap* pOldBitmap = bitmapDC.SelectObject(&bitmap);

pDC->BitBlt(0, 0, bmpInfo.bmWidth, bmpInfo.bmHeight, &bitmapDC, 
            0, 0, SRCCOPY);

bitmapDC.SelectObject(pOldBitmap);
bitmap.DeleteObject();

That's all for now.

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)