Blurring data

A box blur implementation for 1D, 2D, and RGBA images; supports fractional radius.

blur(data, radius)

const numbers = d3.cumsum({length: 1000}, () => Math.random() - 0.5);
d3.blur(numbers, 5); // a smoothed random walk

Examples · Source · Blurs an array of data in-place by applying three iterations of a moving average transform (box filter) for a fast approximation of a Gaussian kernel of the given radius, a non-negative number. Returns the given data.

blur2({data, width, height}, rx, ry)

const matrix = {
  width: 4,
  height: 3,
  data: [
    1, 0, 0, 0,
    0, 0, 0, 0,
    0, 0, 0, 1
  ]
};

d3.blur2(matrix, 1);

Examples · Source · Blurs a matrix of the given width and height in-place by applying a horizontal blur of radius rx and a vertical blur of radius ry (which defaults to rx). The matrix values data are stored in a flat (one-dimensional) array. If height is not specified, it is inferred from the given width and data.length. Returns the blurred matrix {data, width, height}.

blurImage(imageData, rx, ry)

const imageData = context.getImageData(0, 0, width, height);
d3.blurImage(imageData, 5);

Examples · Source · Blurs the given ImageData in-place, blurring each of the RGBA layers independently by applying an horizontal blur of radius rx and a vertical blur of radius ry (which defaults to rx). Returns the blurred ImageData.