[Gavino]

Originally Posted by henryho_hk

    assert(dst_w == floor(dst_w/unit_w)*unit_w, ...)
    assert(dst_h == floor(dst_h/unit_h)*unit_h, ...)

'floor' is redundant here - since dst_w and unit_w are both integers, so is dst_w/unit_w.

So you could simplify it to

    assert(dst_w == (dst_w/unit_w)*unit_w, ...)

or even more simply

    assert(dst_w % unit_w == 0, ...)