Allow max image side length to be configurable

docs/config.rst

@@ -23,7 +23,8 @@ Example::
         "png": 90,
         "jpeg": 80,
         "webp": 90
-      }
+      },
+      "maxSize": 2048
     },
     "styles": {
       "basic": {
@@ -69,6 +70,11 @@ You can use this to optionally specify on what domains the rendered tiles are ac
 
 Quality of the compression of individual image formats. [0-100]
 
+``maxSize``
+-----------
+
+Maximum image side length to be allowed to be rendered (including scale factor). Default is ``2048``.
+
 ``styles``
 ==========
 

src/serve_rendered.js

@@ -254,7 +254,7 @@ module.exports = function(options, repo, params, id, dataResolver) {
       return res.status(400).send('Invalid center');
     }
     if (Math.min(width, height) <= 0 ||
-        Math.max(width, height) * scale > 2048) {
+        Math.max(width, height) * scale > (options.maxSize || 2048)) {
       return res.status(400).send('Invalid size');
     }
     if (format == 'png' || format == 'webp') {