Magnifying a shrunken image --- without using imageData

[Roger.E.Eller at sealedair.com]

Dave,

I have been working on the problem since you posted your first suggestion, 
and you were exactly right. Now I am trying to work out the position 
correlation between the scaled image and the full size image in a window. 
Your method maintains the original quality like I want it to.

Thanks.
Roger Eller <roger.e.eller at sealedair.com>


> Hi,
> 
> Well maybe I misunderstand the problem then!
> 
> In my case I have images that are around 1500 x 500 pixels  in size.
> I show a preview of this in a separate image which is scaled so the
> width is 250 pixels and the height adjusts depending on the aspect
> ratio. From re-reading the original post,  Roger wants to take a
> portion of the smaller preview image and scale it up. If you scale
> from the preview, then a lot of data has already been lost, so he
> wants to get the data from the original image, scaled from the
> preview. If you take the data from the preview and then scale it, it
> will become pixilated, the extent of this pixelation will obviously
> depend on the size of the original and the size of the preview. In my
> case the loss was just too great, and anyway, it's still much better
> to scale from the original if you are looking for the best quality.
> 
> All the Best
> Dave
> 
> 
>>I tried it - works fine. The original imagedata is contained in the
>>copied image - so no problem with pixel loss.