Allow withMetadata to set density #967

lib/constructor.js

@@ -231,6 +231,7 @@ const Sharp = function (input, options) {
     streamOut: false,
     withMetadata: false,
     withMetadataOrientation: -1,
+    withMetadataDensity: 0,
     withMetadataIcc: '',
     withMetadataStrs: {},
     resolveWithObject: false,

lib/output.js

@@ -150,7 +150,7 @@ function toBuffer (options, callback) {
  *
  * @example
  * // Set "IFD0-Copyright" in output EXIF metadata
- * await sharp(input)
+ * const data = await sharp(input)
  *   .withMetadata({
  *     exif: {
  *       IFD0: {
@@ -160,10 +160,17 @@ function toBuffer (options, callback) {
  *   })
  *   .toBuffer();
  *
+ *  * @example
+ * // Set output metadata to 96 DPI
+ * const data = await sharp(input)
+ *   .withMetadata({ density: 96 })
+ *   .toBuffer();
+ *
  * @param {Object} [options]
  * @param {number} [options.orientation] value between 1 and 8, used to update the EXIF `Orientation` tag.
  * @param {string} [options.icc] filesystem path to output ICC profile, defaults to sRGB.
  * @param {Object<Object>} [options.exif={}] Object keyed by IFD0, IFD1 etc. of key/value string pairs to write as EXIF data.
+ * @param {number} [options.density] Number of pixels per inch (DPI).
  * @returns {Sharp}
  * @throws {Error} Invalid parameters
  */
@@ -177,6 +184,13 @@ function withMetadata (options) {
         throw is.invalidParameterError('orientation', 'integer between 1 and 8', options.orientation);
       }
     }
+    if (is.defined(options.density)) {
+      if (is.number(options.density) && options.density > 0) {
+        this.options.withMetadataDensity = options.density;
+      } else {
+        throw is.invalidParameterError('density', 'positive number', options.density);
+      }
+    }
     if (is.defined(options.icc)) {
       if (is.string(options.icc)) {
         this.options.withMetadataIcc = options.icc;