2. A method for gaze-controlled text size control, comprising: probing, sampling and recording a user's horizontal gaze signal at a predefined sampling frequency; subjecting the horizontal gaze signal to a transform; detecting, in the transformed horizontal gaze signal, line delimiters; deriving, for each pair of consecutive line delimiters enclosing the transformed horizontal gaze signal of a current line, a reading speed from the distance in samples of the pair of line delimiters, in relation to the sampling frequency of the horizontal gaze signal; determining, from the transformed horizontal gaze signal of the current line, a number of saccades in the current line, by counting those locations, where the horizontal gaze signal has a sudden high slope portion surrounded on both sides by portions of markedly smaller slope; wherein an increase of the font size is initiated if the number of saccades is above a first threshold or if the reading speed is below a second threshold, and a decrease of the font size is initiated if the number of saccades is less than a third threshold; and wherein the horizontal gaze signal, before the detecting of the line delimiters, is calibrated in such a way that an amplitude difference of 1 in the calibrated signal matches width of text being read.
2. A method for gaze-controlled text size control, comprising: probing, sampling and recording a user's horizontal gaze signal at a predefined sampling frequency; subjecting the horizontal gaze signal to a transform; detecting, in the transformed horizontal gaze signal, line delimiters; deriving, for each pair of consecutive line delimiters enclosing the transformed horizontal gaze signal of a current line, a reading speed from the distance in samples of the pair of line delimiters, in relation to the sampling frequency of the horizontal gaze signal; determining, from the transformed horizontal gaze signal of the current line, a number of saccades in the current line, by counting those locations, where the horizontal gaze signal has a sudden high slope portion surrounded on both sides by portions of markedly smaller slope; wherein an increase of the font size is initiated if the number of saccades is above a first threshold or if the reading speed is below a second threshold, and a decrease of the font size is initiated if the number of saccades is less than a third threshold; and wherein the horizontal gaze signal, before the detecting of the line delimiters, is calibrated in such a way that an amplitude difference of 1 in the calibrated signal matches width of text being read. 3. The method of claim 2 wherein the transform subjected to by the horizontal gaze signal is a frequency transform.