Blended transfer function for computer pointing devices
View Patent ↗A transfer function is provided for use with computer pointing devices such as trackpads. The transfer function includes a first component having characteristics of a positional transfer function and a second component having characteristics of a velocity-based transfer function. The first (positional) component and the second (velocity-based) component of the transfer function are blended so that the transfer function exhibits purely positional behavior in response to a first range of inputs and exhibits combined positional and velocity-based behavior in response to a second range of inputs. The first range of inputs may, for example, correspond to a region in the input coordinate space that is bounded by a circle having a predetermined threshold radius.
1. A computer-implemented method for use with a pointing device for providing input to a computing device, the method comprising:
determining whether input coordinates of an input vector are within a first region of an input coordinate space, the input coordinate space being associated with the pointing device and comprising the first region and a second region; and
if the input coordinates are determined not to be within the first region, then:
selecting a first transfer function, the first transfer function comprising a non-constant function relating the input vector to velocity; and
selecting a position and velocity of an on-screen pointer based on the first transfer function;
wherein:
the first transfer function relating to the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
h comprises a vector representing a center of a positional range of the pointer,
kp comprises a positional gain, and the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r , and
kv comprises a velocity gain.
2. The method of claim 1 , further comprising:
if the input coordinates are determined to be within the first region, then:
selecting a second transfer function; and
selecting the position and velocity of the on-screen pointer based on the second transfer function.
3. The method of claim 2 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer,
wherein kp comprises a positional gain, and wherein the second transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
4. The method of claim 3 , further comprising:
identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
setting the coordinates of the home vector h equal to the identified coordinates.
5. The method of claim 1 , further comprising steps of:
identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
setting the coordinates of the home vector h equal to the identified coordinates.
6. The method of claim 1 , wherein the first region comprises a region bounded by a rectangle.
7. The method of claim 1 ,
wherein the first region comprises a region within a first transition radius of a center of the input coordinate space associated with the pointing device.
8. An apparatus for use with a pointing device for providing input to a computing device, the apparatus comprising:
determination means for determining whether input coordinates of an input vector are within a first region of an input coordinate space, the input coordinate space being associated with the pointing device and comprising the first region and a second region; and
first selection means for selecting a first transfer function and selecting a position and velocity of an on-screen pointer based on the first transfer function if the input coordinates are determined not to be within the first region, the first transfer function comprising a non-constant function relating the input vector to velocity;
wherein:
the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
h comprises a vector representing a center of a positional range of the pointer,
kp comprises a positional gain, and the first transfer function relates the velocity dh/dt of the on-screen pointer to the input vector r using the formula:
dh/dt=kv*r, and
kv comprises a velocity gain.
9. The apparatus of claim 8 , further comprising:
second selection means for selecting a second transfer function and selecting the position and velocity of the on-screen pointer based on the second transfer function if the input coordinates are determined to be within the first region.
10. The apparatus of claim 9 , wherein the second transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
wherein h comprises a vector representing a center of a positional range of the pointer,
wherein kp comprises a positional gain, and
wherein the second transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
11. The apparatus of claim 10 , further comprising:
means for identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
means for setting the coordinates of the home vector h equal to the coordinates identified by the means for identifying.
12. The apparatus of claim 8 , further comprising:
means for identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
means for setting the coordinates of the home vector h equal to the identified coordinates.
13. The apparatus of claim 8 , wherein the first region comprises a region bounded by a rectangle.
14. The apparatus of claim 8 , wherein the first region comprises a region within a first transition radius of a center of the input coordinate space associated with the pointing device.
15. The method of claim 8 , wherein the first region comprises a region within a first transition radius of a center of the input coordinate space associated with the pointing device.
16. A computer-implemented method for use with a pointing device for providing input to a computing device, the method comprising:
determining whether input coordinates of an input vector are within a first region of an input coordinate space, the input coordinate space being associated with the pointing device and comprising the first region and a second region; and
if the input coordinates are determined to be within the first region, then:
selecting a first transfer function; and
selecting the position and velocity of the on-screen pointer based on the first transfer function;
wherein:
the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
h comprises a vector representing a center of a positional range of the pointer, and
kp comprises a positional gain, and the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
17. The method of claim 16 , further comprising:
identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
setting the coordinates of the home vector h equal to the identified coordinates.
18. The method of claim 16 , wherein the first region comprises a region bounded by a rectangle.
19. The apparatus of claim 16 , wherein the first region comprises a region bounded by a rectangle.
20. An apparatus for use with a pointing device for providing input to a computing device, the apparatus comprising:
determination means for determining whether input coordinates of an input vector are within a first region of an input coordinate space, the input coordinate space being associated with the pointing device and comprising the first region and a second region; and
first selection means for selecting a first transfer function and selecting a position and velocity of an on-screen pointer based on the first transfer function if the input coordinates are determined to be within the first region,
wherein:
the first transfer function relates the position p of the on-screen pointer to the input vector r using the formula:
p=h+kp*r,
h comprises a vector representing a center of a positional range of the pointer,
kp comprises a positional gain, and
the first transfer function relates the velocity dh/dt of the center of the positional range of the pointer to the input vector r using the formula:
dh/dt= 0.
21. The apparatus of claim 20 , further comprising:
means for identifying coordinates of the on-screen pointer upon commencement of a pointing operation; and
means for setting the coordinates of the home vector h equal to the coordinates identified by the means for identifying.
22. The apparatus of claim 20 , wherein the first region comprises a region within a first transition radius of a center of the input coordinate space associated with the pointing device.