Imagine a simple camera app for a touch screen phone. The app can't use any hardware buttons and needs no other controls than one button to take the picture.
Some things to consider/ideas:
- Phone cameras are used in all sorts on contexts. From self portraits with the screen away from the user, to groups pubs and clubs (tipsy, dancing users in groups) or just straight forward photography where the photographer doesn't want any graphics interrupting the image.
- Fitts' law might suggest just making the whole screen a button
- But touching anywhere on the screen to take a photo would result in accidental captures.
- Maybe corners would be easy for fingers to locate when the screen isn't being looked at. But on some phones this might not be obvious by touch.
- Gestures might be a way to do away with a 'button', but might be slower to take the photo.
- Multi-touch could be used. First touch primes the camera, second touch takes the photo? (this may be tricky if used single handed).
- Using the accelerometer to take photos when the camera is shaken might solve my problems but probably won't result in user's that are happy with the results ;-)
Anyway - how would you place the button or trigger the photo to be taken?