Allow EXIF metadata to be set/update #650

docs/api-output.md

@@ -119,6 +119,7 @@ sRGB colour space and strip all metadata, including the removal of any ICC profi
 -   `options` **[Object][6]?** 
     -   `options.orientation` **[number][9]?** value between 1 and 8, used to update the EXIF `Orientation` tag.
     -   `options.icc` **[string][2]?** filesystem path to output ICC profile, defaults to sRGB.
+    -   `options.exif` **[Object][6]<[Object][6]>** Object keyed by IFD0, IFD1 etc. of key/value string pairs to write as EXIF data. (optional, default `{}`)
 
 ### Examples
 
@@ -129,6 +130,19 @@ sharp('input.jpg')
   .then(info => { ... });
 ```
 
+```javascript
+// Set "IFD0-Copyright" in output EXIF metadata
+await sharp(input)
+  .withMetadata({
+    exif: {
+      IFD0: {
+        Copyright: 'Wernham Hogg'
+      }
+    }
+  })
+  .toBuffer();
+```
+
 -   Throws **[Error][4]** Invalid parameters
 
 Returns **Sharp** 

docs/changelog.md

@@ -8,6 +8,9 @@ Requires libvips v8.10.6
 
 * Ensure all installation errors are logged with a more obvious prefix.
 
+* Allow `withMetadata` to set and update EXIF metadata.
+  [#650](https://github.com/lovell/sharp/issues/650)
+
 * Add support for OME-TIFF Sub Image File Directories (subIFD).
   [#2557](https://github.com/lovell/sharp/issues/2557)