Add experimental sharpness calc to stats #2251

lib/input.js

@@ -299,6 +299,7 @@ function metadata (callback) {
  *     - `maxY` (y-coordinate of one of the pixel where the maximum lies)
  * - `isOpaque`: Is the image fully opaque? Will be `true` if the image has no alpha channel or if every pixel is fully opaque.
  * - `entropy`: Histogram-based estimation of greyscale entropy, discarding alpha channel if any (experimental)
+ * - `sharpness`: Estimation of greyscale sharpness based on the standard deviation of a Laplacian convolution, discarding alpha channel if any (experimental)
  *
  * @example
  * const image = sharp(inputJpg);
@@ -308,6 +309,9 @@ function metadata (callback) {
  *      // stats contains the channel-wise statistics array and the isOpaque value
  *   });
  *
+ * @example
+ * const { entropy, sharpness } = await sharp(input).stats();
+ *
  * @param {Function} [callback] - called with the arguments `(err, stats)`
  * @returns {Promise<Object>}
  */