Snapping to pixels when transforming

Hi all,
I'm haivng some trouble using the free transform tool. I've finally figured out how to make a rectangle shape snap to pixels when drawing it (so there are no semitransparent bits on the edges) but when it comes to transforming it (or any bitmap for that matter) I can't work out how to constrain it.

Can anyone help me free transform an object and have it snap to actual pixels to avoid the semitransparency on solid edges?

Thanks!

Press the shift key.

Note that even with the snap to pixels turned on (I assume your using a 1 pixel grid) you may get anti-aliasing when keeping things in proportion.

An example: A 75 x 100 pixel rectangle is scaled down to 50 pixels in lenght, the width is now 37.5 pixels. There must thus be some anti-aliasing to maintain the appearance of proportion

It's as simple as that? I thought holding down shift just meant that it scaled to the same ratio as originally. I hadn't actually considered a 1px grid but that actually sounds like it might do the job as well as I need it to!

Thanks :)

I can't work out how to constrain it.

My suggestion to press the shift key was in answer to that part of your original post.

My mention of the anti-aliasing was there to let you know that the semi-transparent edges will pretty much always be there