3 ms·

PNG defines 5 possible filter methods per row: 0 = None, 1 = Sub, 2 = Up, 3 = Average, 4 = Paeth. Brute-forcing the filter search is exponential time at Θ(5^ima

by nayuki 5y ago

PNG defines 5 possible filter methods per row: 0 = None, 1 = Sub, 2 = Up, 3 = Average, 4 = Paeth. Brute-forcing the filter search is exponential time at Θ(5^imageHeight). https://www.w3.org/TR/2003/REC-PNG-20031110/#9Filters https://www.w3.org/TR/2003/REC-PNG-20031110/#9Filters