Add keepXmp and withXmp for control over output XMP metadata #4416

lib/output.js

@@ -312,6 +312,59 @@ function withIccProfile (icc, options) {
   return this;
 }
 
+/**
+ * Keep XMP metadata from the input image in the output image.
+ *
+ * @since 0.34.3
+ *
+ * @example
+ * const outputWithXmp = await sharp(inputWithXmp)
+ *   .keepXmp()
+ *   .toBuffer();
+ *
+ * @returns {Sharp}
+ */
+function keepXmp () {
+  this.options.keepMetadata |= 0b00010;
+  return this;
+}
+
+/**
+ * Set XMP metadata in the output image.
+ *
+ * Supported by PNG, JPEG, WebP, and TIFF output.
+ *
+ * @since 0.34.3
+ *
+ * @example
+ * const xmpString = `
+ *   <?xml version="1.0"?>
+ *   <x:xmpmeta xmlns:x="adobe:ns:meta/">
+ *     <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+ *       <rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements/1.1/">
+ *         <dc:creator><rdf:Seq><rdf:li>John Doe</rdf:li></rdf:Seq></dc:creator>
+ *       </rdf:Description>
+ *     </rdf:RDF>
+ *   </x:xmpmeta>`;
+ *
+ * const data = await sharp(input)
+ *   .withXmp(xmpString)
+ *   .toBuffer();
+ *
+ * @param {string} xmp String containing XMP metadata to be embedded in the output image.
+ * @returns {Sharp}
+ * @throws {Error} Invalid parameters
+ */
+function withXmp (xmp) {
+  if (is.string(xmp) && xmp.length > 0) {
+    this.options.withXmp = xmp;
+    this.options.keepMetadata |= 0b00010;
+  } else {
+    throw is.invalidParameterError('xmp', 'non-empty string', xmp);
+  }
+  return this;
+}
+
 /**
  * Keep all metadata (EXIF, ICC, XMP, IPTC) from the input image in the output image.
  *
@@ -1576,6 +1629,8 @@ module.exports = function (Sharp) {
     withExifMerge,
     keepIccProfile,
     withIccProfile,
+    keepXmp,
+    withXmp,
     keepMetadata,
     withMetadata,
     toFormat,