Personally I think pinch-to-zoom doesn't work very well anyway. It always seems to zoom in too quickly or too slowly; the amount of zoom seems arbitrary.
What I've always wanted was to be able to put two fingers to mark the top left and bottom right of a bounding box which would mark how much to zoom in and hold for, say, half a second. To zoom out use two fingers to mark the top right and bottom left of the bounding box you want the current screen to zoom out to (again hold for half a second). This would be much more accurate. The time delay is to allow for mis-taps and to give the user time to get the bounding box the right size.
A variation would be similar but would be something like:
- hold two fingers on the screen until you get a bounding box like above.
- move the bounding box to the correct size.
- let go and the zoom happens.
With this method you could cancel the zoom action by collapsing the bounding box on itself vertically or horizontally.
What I've always wanted was to be able to put two fingers to mark the top left and bottom right of a bounding box which would mark how much to zoom in and hold for, say, half a second. To zoom out use two fingers to mark the top right and bottom left of the bounding box you want the current screen to zoom out to (again hold for half a second). This would be much more accurate. The time delay is to allow for mis-taps and to give the user time to get the bounding box the right size.
A variation would be similar but would be something like:
- hold two fingers on the screen until you get a bounding box like above.
- move the bounding box to the correct size.
- let go and the zoom happens.
With this method you could cancel the zoom action by collapsing the bounding box on itself vertically or horizontally.