Attached you find a working program.
The problem was the bitmap size.
I tested it on my Nexus One 480 x 800 x 1.5
The imageview dimension is 300dip = 450 pixels.
The bitmap dimension is 380 pixels.
The bitmap property of the imageview points onto the original bitmap and the original bitmaps dimension which are not the same.
I added a canvas for the imageview and draw the bitmap onto it so the imageview bitmap has the same dimensions as the imageview (450) not the original ones (380).
Best regards.