(C++ ) Dealing with StretchBlt() and AlphaBlend() 's image size limitations (32768)?

Question

As I learned from bitter experience, these two MSDN functions will refuse to display an image that is wider than 32 767 logical units.

My aim is to create a zoomable image display of very large images (as wide as 262,144 pixels but only as high as a few hundred).

BOOL AlphaBlend(
   int xDest,
   int yDest,
   int nDestWidth,
   int nDestHeight,
   CDC* pSrcDC,
   int xSrc,
   int ySrc,
   int nSrcWidth,
   int nSrcHeight,
   BLENDFUNCTION blend 
);

I get two types of problems with the above arguments:

1) nSrcWidth is simply too large and the image doesn't get displayed. Chopping the image into parts won't work because then xDest will be too large.

2) When zooming I magnify the image and nDestWidth becomes too large; as a result zooming more than a given ratio makes the image disappear.

Is there some function/class/method I could use to avoid these limitations or am I forced to work around them?

Thanks in advance for any help.