Add white border to clear icon

Useful when background is the same color as the gray of the cross.

Libs/Widgets/Resources/Icons/clear2.svg

@@ -51,6 +51,9 @@
        y2="609"
        gradientUnits="userSpaceOnUse"
        gradientTransform="matrix(0,-0.5462895,0.5462895,0,-604.7214,629.48684)" />
+    <filter id="white-border_blur">
+      <feGaussianBlur stdDeviation="0.2" in="SourceGraphic"/>
+    </filter>
   </defs>
   <sodipodi:namedview
      id="base"
@@ -82,6 +85,10 @@
       </cc:Work>
     </rdf:RDF>
   </metadata>
+  <g display="inline" id="layer1">
+    <title>Background</title>
+    <path filter="url(#white-border_blur)" stroke-linejoin="round" stroke-width="1" stroke="#ffffff" fill="none" stroke-miterlimit="4" id="white-border" d="m6.11337,7.32074l4.74588,4.74585l-4.72882,4.74591l1.10965,1.092529l4.72882,-4.728819l4.72882,4.728819l1.09259,-1.092529l-4.72882,-4.72882l4.762969,-4.76294l-1.109678,-1.10968l-4.745881,4.763l-4.76297,-4.763l-1.09256,1.10968z"/>
+  </g>
   <g
      inkscape:label="Layer 1"
      inkscape:groupmode="layer"

Libs/Widgets/Testing/Cpp/ctkSearchBoxTest1.cpp

@@ -21,8 +21,9 @@
 // Qt includes
 #include <QApplication>
 #include <QDebug>
-#include <QVBoxLayout>
+#include <QPalette>
 #include <QTimer>
+#include <QVBoxLayout>
 
 // CTK includes
 #include "ctkSearchBox.h"
@@ -36,8 +37,13 @@ int ctkSearchBoxTest1(int argc, char* argv[])
 {
   QApplication app(argc, argv);
 
+  QPalette p;
+  p.setColor(QPalette::ColorRole::Window, Qt::gray);
+  p.setColor(QPalette::ColorRole::Base, Qt::gray);
+
   ctkSearchBox search;
   search.setShowSearchIcon(true);
+  search.setPalette(p);
   search.show();
 
   QWidget topLevel;