add support for direct-image-filters

lib/carto/tree/style.js

@@ -5,13 +5,16 @@ var _ = require('underscore');
 // return a stringified style for Mapnik
 tree.StyleXML = function(name, attachment, definitions, env) {
     var existing = {};
-    var image_filters = [], comp_op = [], opacity = [];
+    var image_filters = [], direct_image_filters = [], comp_op = [], opacity = [];
 
     for (var i = 0; i < definitions.length; i++) {
         for (var j = 0; j < definitions[i].rules.length; j++) {
             if (definitions[i].rules[j].name === 'image-filters') {
                 image_filters.push(definitions[i].rules[j]);
             }
+            if (definitions[i].rules[j].name === 'direct-image-filters') {
+                direct_image_filters.push(definitions[i].rules[j]);
+            }
             if (definitions[i].rules[j].name === 'comp-op') {
                 comp_op.push(definitions[i].rules[j]);
             }
@@ -35,6 +38,14 @@ tree.StyleXML = function(name, attachment, definitions, env) {
         }).value().join(',') + '"';
     }
 
+    if (direct_image_filters.length) {
+        attrs_xml += ' direct-image-filters="' + _.chain(image_filters)
+            // prevent identical filters from being duplicated in the style
+            .uniq(function(i) { return i.id; }).map(function(f) {
+            return f.ev(env).toXML(env, true, ',', 'direct-image-filter');
+        }).value().join(',') + '"';
+    }
+
     if (comp_op.length) {
         attrs_xml += ' comp-op="' + comp_op[0].value.ev(env).toString() + '"';
     }

test/rendering-mss/scale-hsla-filter.mss

@@ -0,0 +1,5 @@
+#layer {
+   polygon-fill:red;
+   image-filters:scale-hsla(.5,.5,.5,.5,.5,.5,.5,.5);
+   direct-image-filters:scale-hsla(.5,.5,.5,.5,.5,.5,.5,.5);
+}

test/rendering-mss/scale-hsla-filter.xml

@@ -0,0 +1,5 @@
+<Style name="style" filter-mode="first" image-filters="scale-hsla(0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5)" direct-image-filters="scale-hsla(0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.5)">
+  <Rule>
+    <PolygonSymbolizer fill="#ff0000" />
+  </Rule>
+</Style>