1 files changed, 46 insertions, 0 deletions
diff --git a/src/sp-filter.cpp b/src/sp-filter.cpp
index c3e7d217e..e8319baca 100644
--- a/src/sp-filter.cpp
+++ b/src/sp-filter.cpp
@@ -28,6 +28,7 @@ using std::pair;
 #include "sp-filter.h"
 #include "sp-filter-reference.h"
 #include "sp-filter-primitive.h"
+#include "sp-item.h"
 #include "uri.h"
 #include "xml/repr.h"
 #include <cstring>
@@ -206,10 +207,55 @@ void SPFilter::update(SPCtx *ctx, guint flags) {
     if (flags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG |
                  SP_OBJECT_VIEWPORT_MODIFIED_FLAG)) {
 
+        SPItemCtx *ictx = (SPItemCtx *) ctx;
+
+        // Do here since we know viewport (Bounding box case handled during rendering)
+        // Note: This only works for root viewport since this routine is not called after
+        // setting a new viewport. A true fix requires a strategy like SPItemView or SPMarkerView.
+        if(this->filterUnits == SP_FILTER_UNITS_USERSPACEONUSE) {
+            if (this->x.unit == SVGLength::PERCENT) {
+                this->x._set = true;
+                this->x.computed = this->x.value * ictx->viewport.width();
+            }
+
+            if (this->y.unit == SVGLength::PERCENT) {
+                this->y._set = true;
+                this->y.computed = this->y.value * ictx->viewport.height();
+            }
+
+            if (this->width.unit == SVGLength::PERCENT) {
+                this->width._set = true;
+                this->width.computed = this->width.value * ictx->viewport.width();
+            }
+
+            if (this->height.unit == SVGLength::PERCENT) {
+                this->height._set = true;
+                this->height.computed = this->height.value * ictx->viewport.height();
+            }
+        }
         /* do something to trigger redisplay, updates? */
 
     }
 
+    // Update filter primitives in order to update filter primitive area
+    // (SPObject::ActionUpdate is not actually used)
+    unsigned childflags = flags;
+
+    if (flags & SP_OBJECT_MODIFIED_FLAG) {
+      childflags |= SP_OBJECT_PARENT_MODIFIED_FLAG;
+    }
+    childflags &= SP_OBJECT_MODIFIED_CASCADE;
+
+    GSList *l = g_slist_reverse(this->childList(true, SPObject::ActionUpdate));
+    while (l) {
+        SPObject *child = SP_OBJECT (l->data);
+        l = g_slist_remove (l, child);
+        if( SP_IS_FILTER_PRIMITIVE( child ) ) {
+            child->updateDisplay(ctx, childflags);
+        }
+        sp_object_unref(child);
+    }
+
     SPObject::update(ctx, flags);
 }