Soft control user interface with touchpad input device

1. A method comprising:

by a computing device, displaying on a display of the computing device a graphical parameter-control element in a graphical user interface indicating a range and a position value of a controllable parameter of an application of the computing device;

by the computing device, detecting a touch event on a touch-sensitive surface of the computing device; and

by the computing device, determining that the touch event is a scrolling event, and scrolling the position value along the range based on a direction of the scrolling event, wherein the position value is adjusted by a relative amount within the range mapping to a relative distance of the scrolling event along the touch-sensitive surface.

2. The method of claim 1 , wherein the touch-sensitive surface is a side-mounted touchpad.

3. The method of claim 1 , wherein the relative distance of the scrolling event comprises a ratio between:

a distance between start and end locations of the scrolling event; and

a total length of the touch-sensitive surface.

4. The method of claim 1 , wherein:

the application of the computing device is a camera application;

the controllable parameter is a zoom level of the camera application;

the graphical parameter-control element is a zoom bar;

the range is a zoom range of the camera application; and

the position value corresponds to a zoom-level value of the camera application.

5. The method of claim 1 , wherein:

the application of the computing device is a media-player application;

the controllable parameter is progress of playback of media by the media-player application;

the graphical parameter-control element is a playback-progress bar;

the range is a playback time of the media; and

the position value corresponds to a point in the playback time of the media.

6. The method of claim 1 , wherein the display of the graphic parameter-control element in the graphical user interface is based on an orientation of the computing device.

7. A device comprising:

a display;

a touch-sensitive surface;

one or more processors; and

a memory coupled to the processors comprising instructions executable by the processors, the processors being operable when executing the instructions to:

display on the display a graphical parameter-control element in a graphical user interface indicating a range and a position value of a controllable parameter of an application of the device;

detect a touch event on the touch-sensitive surface; and

determine that the touch event is a scrolling event, and scroll the position value along the range based on a direction of the scrolling event, wherein the position value is adjusted by a relative amount within the range mapping to a relative distance of the scrolling event along the touch-sensitive surface.

8. The device of claim 7 , wherein the touch-sensitive surface is a side-mounted touchpad.

9. The device of claim 7 , wherein the relative distance of the scrolling event comprises a ratio between:

a distance between start and end locations of the scrolling event; and

a total length of the touch-sensitive surface.

10. The device of claim 7 , wherein the display of the graphical parameter-control element in the graphical user interface is based on an orientation of the device.

11. The device of claim 7 wherein:

the application of the device is a camera application;

the controllable parameter is a zoom level of the camera application;

the graphical parameter-control element is a zoom bar;

the range is a zoom range of the camera application; and

the position value corresponds to a zoom-level value of the camera application.

12. The device of claim 7 , wherein:

the application of the device is a media-player application;

the controllable parameter is progress of playback of media by the media-player application;

the graphical parameter-control element is a playback-progress bar;

the range is a playback time of the media; and

the position value corresponds to a point in the playback time of the media.

13. One or more computer readable non-transitory storage media embodying software that is operable when executing on a computing device to:

display on the display a graphical parameter-control element in a graphical user interface indicating a range and a position value of a controllable parameter of an application of the device;

detect a touch event on a touch-sensitive surface of the computing device; and

determine that the touch event is a scrolling event, and scroll the position value along the range based on a direction of the scrolling event, wherein the position value is adjusted by a relative amount within the range mapping to a relative distance of the scrolling event along the touch-sensitive surface.

14. The media of claim 13 , wherein the touch-sensitive surface is a side-mounted touchpad.

15. The media of claim 13 , wherein the relative distance of the scrolling event comprises a ratio between:

a distance between start and end locations of the scrolling event; and

a total length of the touch-sensitive surface.

16. The media of claim 13 , wherein the display of the graphic parameter-control element in the graphical user interface is based on an orientation of the computing device.

17. The media of claim 13 , wherein:

the application of the computing device is a camera application;

the controllable parameter is a zoom level of the camera application;

the graphical parameter-control element is a zoom bar;

the range is a zoom range of the camera application; and

the position value corresponds to a zoom-level value of the camera application.

18. The media of claim 13 , wherein:

the application of the computing device is a media-player application;

the controllable parameter is progress of playback of media by the media-player application;

the graphical parameter-control element is a playback-progress bar;

the range is a playback time of the media; and

the position value corresponds to a point in the playback time of the media.