1. A touch sensing system, comprising: a two-dimensional capacitive sense array including a plurality of capacitive sensors; a capacitance measurement circuit coupled to the capacitive sense array and configured to measure capacitance changes at each capacitive sensor of the capacitive sense array; a processing unit coupled to the capacitance measurement circuit, wherein the processing unit is configured for: performing a scan of the capacitive sense array to measure capacitance for at least a plurality of the capacitive sensors; identifying a first capacitive sensor whose measured capacitance is a local peak; identifying a local rectangular array of capacitive sensors around the first capacitive sensor; for each column of the local rectangular array, summing measured capacitances for the capacitive sensors in the column to form a respective column sum; determining whether to apply a smoothing algorithm; in accordance with a determination not to apply the smoothing algorithm, computing an x-coordinate of a touch using a plurality of the column sums; and in accordance with a determination to apply the smoothing algorithm, computing the x-coordinate of the touch as an average of two x-coordinate calculations, wherein each of the two x-coordinate calculations conditionally performs a horizontal shift of the local rectangular array based on comparing the peak measured capacitance of the first capacitive sensor to an adjacent measured capacitance and computes a respective x-coordinate using a respective plurality of the column sums.