additional option for removeUselessFillStroke, to actually remove invisible shapes

plugins/removeUselessStrokeAndFill.js

@@ -8,7 +8,8 @@ exports.description = 'removes useless stroke and fill attributes';
 
 exports.params = {
     stroke: true,
-    fill: true
+    fill: true,
+    removeNone: false
 };
 
 var shape = require('./_collections').elemsGroups.shape,
@@ -87,6 +88,13 @@ exports.fn = function(item, params) {
             }
         }
 
+        if (params.removeNone && 
+            (!stroke || item.hasAttr('stroke') && item.attr('stroke').value=='none') &&
+            (!fill || item.hasAttr('fill') && item.attr('fill').value=='none')) {
+
+            return false;
+        }
+
     }
 
 };

test/plugins/removeUselessStrokeAndFill.02_.svg

@@ -0,0 +1,24 @@
+<svg xmlns="http://www.w3.org/2000/svg">
+    <defs>
+        <g id="test">
+            <rect fill-opacity=".5" width="100" height="100"/>
+        </g>
+    </defs>
+    <circle fill="none" fill-rule="evenodd" cx="60" cy="60" r="50"/>
+    <circle fill="red" fill-opacity="0" cx="90" cy="90" r="50"/>
+    <circle fill-opacity="0" fill-rule="evenodd" cx="90" cy="60" r="50"/>
+    <circle fill="red" fill-opacity=".5" cx="60" cy="60" r="50"/>
+    <g fill="none">
+        <circle fill-opacity=".5" cx="60" cy="60" r="50"/>
+    </g>
+</svg>
+
+@@@
+
+<svg xmlns="http://www.w3.org/2000/svg">
+    <circle fill="red" fill-opacity=".5" cx="60" cy="60" r="50"/>
+</svg>
+
+@@@
+
+{ "removeNone": true }