Expose vips internal cache settings and status

README.md

@@ -51,7 +51,7 @@ Scale and crop to `width` x `height` calling `callback` when complete.
 
 `callback` gets two arguments `(err, buffer)` where `err` is an error message, if any, and `buffer` is the resultant image data when a Buffer is requested.
 
-### Examples
+#### Examples
 
 ```javascript
 sharp.resize("input.jpg", "output.jpg", 300, 200, function(err) {
@@ -101,6 +101,20 @@ sharp.resize("input.jpg", sharp.buffer.webp, 200, 300, {canvas: sharp.canvas.emb
 });
 ```
 
+### cache([limit])
+
+If `limit` is provided, set the `vips` internal cache limit to this value in MB. The default value is 100.
+
+Always returns cache statistics, namely current usage, high water mark and maximum limit.
+
+The high water mark may be higher than the maximum limit.
+
+```javascript
+var stats = sharp.cache(); // { current: 98, high: 115, limit: 100 }
+sharp.cache(200); // { current: 98, high: 115, limit: 200 }
+sharp.cache(50); // { current: 49, high: 115, limit: 50 }
+```
+
 ## Testing
 
 	npm test