diff --git a/src/interface/render_svg.cpp b/src/interface/render_svg.cpp
index ffa2f52b5b3d4285e0b83bfe425480d58e1b7107..19ad923547df19648173d6db5eae6b1a626c4c11 100644
--- a/src/interface/render_svg.cpp
+++ b/src/interface/render_svg.cpp
@@ -2,46 +2,8 @@
 
 using namespace std;
 
-void Svg::rectangle(unsigned long w, unsigned long h,unsigned long x1,unsigned long y1,  unsigned int r,   unsigned int g,   unsigned int b ){
-    _buffer << "<rect title='container' width='" << w
-            <<"' height='"<< h
-            <<"' x='"     << x1
-            <<"' y='"     << y1
-            <<"' fill='rgb("<<r<<","<<g<<","<<b
-            <<")'/>";
-    print();
-}
-
-
-void Svg::line(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2){
-    _buffer << "<line title='line' x1='" << x1
-            <<"' y1='"     << y1
-            <<"' x2='"     << x2
-            <<"' y2='"     << y2
-            <<"' />";
-    print();
-}
-
-
-void Svg::triangle(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2, unsigned long x3,unsigned long y3){
-    _buffer << "<polyline title='triangle' class='triangle' points='"
-            <<        x1 << "," << y1
-            << " " << x2 << "," << y2
-            << " " << x3 << "," << y3
-            <<"' />";
-    print();
-}
-
-void Svg::print(){
-    if (_buffer.str().size()>BUFFER_SIZE){
-        _svg_file.write(_buffer.str().c_str(),  _buffer.str().size());
-        _buffer.flush();
-    }
-}
-
-
 void Svg::init(const char *path){
-    _svg_file.open(path , ofstream::out | ofstream::trunc);
+  _svg_file.open(path , std::ofstream::out | std::ofstream::trunc);
     if (_svg_file.is_open()==false){
         std::cerr<<"unable to open file";
     }
@@ -73,16 +35,3 @@ void Svg::end(){
     _buffer.flush();
     _svg_file.close();
 }
-
-void Svg::draw_container(const Element_pos x, const Element_pos y, const Element_pos w, const Element_pos h){
-    rectangle(w, h, x, y, 0xff, 0x44, 0xcc);
-}
-
-void Svg::draw_arrow(const Element_pos start_time, const Element_pos end_time, const Element_pos start_height, const Element_pos end_height){
-    line(start_time,start_height,end_time,end_height);
-    triangle(end_time,end_height+ARROWSIZE,end_time,end_height-ARROWSIZE,end_time+ARROWSIZE,end_height);//spike
-}
-
-void Svg::draw_state(const Element_pos start , const Element_pos end, const Element_pos level, const Element_pos height, const Element_col r, const Element_col g, const Element_col b){
-    rectangle(end-start,LEVEL - MARGIN, start,level*LEVEL,r , g,  b);
-}
diff --git a/src/interface/render_svg.hpp b/src/interface/render_svg.hpp
index acad38fc77405ac289234cbc14867377531879be..1be72479577271f835ed5f7188fb75c23c758e30 100644
--- a/src/interface/render_svg.hpp
+++ b/src/interface/render_svg.hpp
@@ -29,7 +29,7 @@ private:
     std::ofstream _svg_file;
     inline void print();
     inline void rectangle(unsigned long w, unsigned long h,unsigned long x1,unsigned long y1,  unsigned int r,   unsigned int g,   unsigned int b );
-    inline void line(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2);
+    inline void line( long unsigned int x1, long unsigned int y1, long unsigned int x2, long unsigned int y2);
     inline void triangle(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2, unsigned long x3,unsigned long y3);
 public:
     /*!
@@ -80,6 +80,7 @@ public:
 
     void draw_event(const Element_pos time, const Element_pos height, const Element_pos container_height);
 
+ 
     void end_draw();
 };
 
@@ -114,11 +115,70 @@ inline void Svg::start_draw_states(){
 inline void Svg::end_draw_states(){
 }
 
-inline void Svg::draw_event(const Element_pos time, const Element_pos height,  const Element_pos container_height){
-}
+
 
 inline void Svg::end_draw(){
 }
 
+void Svg::rectangle(unsigned long w, unsigned long h,unsigned long x1,unsigned long y1,  unsigned int r,   unsigned int g,   unsigned int b ){
+    _buffer << "<rect title='container' width='" << w
+            <<"' height='"<< h
+            <<"' x='"     << x1
+            <<"' y='"     << y1
+            <<"' fill='rgb("<<r<<","<<g<<","<<b
+            <<")'/>";
+    print();
+}
+
+
+
+
+
+void Svg::triangle(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2, unsigned long x3,unsigned long y3){
+    _buffer << "<polyline title='triangle' class='triangle' points='"
+            <<        x1 << "," << y1
+            << " " << x2 << "," << y2
+            << " " << x3 << "," << y3
+            <<"' />";
+    print();
+}
+
+void Svg::print(){
+    if (_buffer.str().size()>BUFFER_SIZE){
+        _svg_file.write(_buffer.str().c_str(),  _buffer.str().size());
+        _buffer.flush();
+    }
+}
+
+
+
+
+inline void Svg::line( long unsigned int x1, long unsigned int y1, long unsigned int x2, long unsigned int y2){
+    _buffer << "<line title='line' x1='" << x1
+            <<"' y1='"     << y1
+            <<"' x2='"     << x2
+            <<"' y2='"     << y2
+            <<"' />";
+    print();
+}
+
+inline void Svg::draw_arrow(const Element_pos start_time, const Element_pos end_time, const Element_pos start_height, const Element_pos end_height){
+  Svg::line(start_time,start_height,end_time,end_height);
+  Svg::triangle(end_time,end_height+ARROWSIZE,end_time,end_height-ARROWSIZE,end_time+ARROWSIZE,end_height);//spike
+}
+
+inline void Svg::draw_container(const Element_pos x, const Element_pos y, const Element_pos w, const Element_pos h){
+    Svg::rectangle(w, h, x, y, 0xff, 0x44, 0xcc);
+}
+
+
+
+inline void Svg::draw_state(const Element_pos start , const Element_pos end, const Element_pos level, const Element_pos height, const Element_col r, const Element_col g, const Element_col b){
+  Svg::rectangle(end-start,LEVEL - MARGIN, start,level*LEVEL,r , g,  b);
+}
+
+inline  void Svg::draw_event(const Element_pos time, const Element_pos height, const Element_pos container_height){
+    rectangle(1,container_height*LEVEL, time, container_height, 0xff, 0x44, 0xcc);
+}
 
 #endif // RENDER_SVG
diff --git a/tests/interface/makefile b/tests/interface/makefile
new file mode 100755
index 0000000000000000000000000000000000000000..2aa6c84fcb184806da0c5a55d1efbf7637f6470c
--- /dev/null
+++ b/tests/interface/makefile
@@ -0,0 +1,7 @@
+test_svg.o : test_svg.cpp
+
+render_svg.o: ../../src/interface/render_svg.cpp ../../src/interface/render_svg.hpp
+	g++ -g -c -Wall ../../src/interface/render_svg.cpp -o render_svg.o
+
+test_svg : render_svg.o test_svg.o
+	g++ -g -o test_svg render_svg.o test_svg.o
\ No newline at end of file
diff --git a/tests/interface/test_svg.cpp b/tests/interface/test_svg.cpp
index f5b23770ffa8420f8abe36b93d79460809d4baf6..7e3c67ea9f5e61812d9e521258596b66de2a7c33 100644
--- a/tests/interface/test_svg.cpp
+++ b/tests/interface/test_svg.cpp
@@ -1,5 +1,5 @@
 
-#include "../src/render_svg.hpp"
+#include "../../src/interface/render_svg.hpp"
 using namespace std;
 
 int main()
@@ -13,9 +13,9 @@ int main()
     s.draw_container(0,LEVEL*2,50,100);
     s.draw_container(0,LEVEL*3,50,100);
 
-    s.draw_state(100, 750, 1, 0xff,0xcc,33);
-    s.draw_state(400, 750, 2, 0xff,0xcc,33);
-    s.draw_state(70, 300, 3, 0xff,0xcc,33);
+    s.draw_state(100, 750, 1,NULL, 0xff,0xcc,33);
+    s.draw_state(400, 750, 2,NULL, 0xff,0xcc,33);
+    s.draw_state(70, 300, 3,NULL, 0xff,0xcc,33);
 
     s.draw_arrow(100,700,LEVEL*1,LEVEL*3);
     s.draw_arrow(200,400,LEVEL*2,LEVEL*2);