There is quite a debate amongst web designers about the relative merits of using zoom vs. using font size to make a page more accessible. Many folks lobby for font-size as the option of choice. Others suggest that zoom is a better representation of page content since it preserves the original layout — just larger or smaller.
My mother has severe Macular Degeneration. I have watched how she works with her various magnifying tools. She is quite used to scrolling both vertical and horizontal. It has become part of her life style.
However, zoom as it is implemented is missing one very significant feature. I call it the “photoshop hand”. Photoshop just happens to be the first place I was introduced to this UI tool. By combining a keyboard shortcut with the mouse one can “grab” the canvas and move it around. It can be moved up, down, left, right, and at any angle. This is very convenient for navigating an image that is larger than the view port.
I have not found this movement tool in the Firefox Zoom feature. If there is one please let me know, my mother will be most pleased. As it is the keyboard arrow keys to some good effect.
If Zoom is designed for use by the visually impaired then it would make sense for it to duplicate the look AND feel of the equipment already in use — such as the table top overhead project type camera and screen. Or, at least for the UI (user interface) designers to study those tools for a bit.
Obviously computer browsers could have expanded functionality beyond the mechanically limited user interface of desktop camera systems. For example, a simple button to jump from h? to h? within a page might be nice. These are semantically the deliminators of distinct areas of a page. Whether or not this would truly be a good idea is left to testing. And testing is something that seems to be missing from many of the accessibility features at the moment.