Patent ID: 8341558

Claim:
A computer-implemented user interface method, comprising: displaying information on a touchscreen of a computing device; receiving from a user of the device an input drawn on the touchscreen; correlating a vector representation of the input to a vector representation of a template, where the correlating comprises employing a closed-form solution to find a rotation that reduces angular distance between the input and the template; where the employing comprises calculating the rotation, θ optimal , in accordance with a first equation, θ optimal = arc ⁢ ⁢ tan ⁢ b a , where a = v t · v g = ∑ i = 1 n ⁢ ( x t ⁢ ⁢ i ⁢ x g ⁢ ⁢ i + y t ⁢ ⁢ i ⁢ y g ⁢ ⁢ i ) , and ⁢ ⁢ b = ∑ i = 1 n ⁢ ( x t ⁢ ⁢ i ⁢ y g ⁢ ⁢ i - y t ⁢ ⁢ i ⁢ x g ⁢ ⁢ i ) , v t corresponds to the vector representation of the template, v g corresponds to the vector representation of the input, x t corresponds to a first coordinate of v t , x g corresponds to a first coordinate of v g , y t corresponds to a second coordinate of v t , and y g corresponds to a second coordinate of v g ; and providing output based on a result of the correlating.