diff --git a/src/lib/aqdiagram/graph/w_viewport.c b/src/lib/aqdiagram/graph/w_viewport.c
index 11ad098..c581eac 100644
--- a/src/lib/aqdiagram/graph/w_viewport.c
+++ b/src/lib/aqdiagram/graph/w_viewport.c
@@ -34,12 +34,6 @@ static void _drawCurves(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc);
 static void _drawCurve(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
                        double minValueX, double maxValueX, double minValueY, double maxValueY,
                        int pen);
-static void _drawCurveLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
-                            double minValueX, double maxValueX, double minValueY, double maxValueY,
-                            int pen);
-static void _drawCurvePoints(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
-                             double minValueX, double maxValueX, double minValueY, double maxValueY,
-                             int pen);
 static void _drawVerticalGrid(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc);
 static void _drawHorizontalGrid(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc);
 static int _screenDistBetweenLevelTicksX(const AQDG_GRAPH_TICK_LIST *tickList, int lvl,
@@ -47,6 +41,16 @@ static int _screenDistBetweenLevelTicksX(const AQDG_GRAPH_TICK_LIST *tickList, i
 static int _screenDistBetweenLevelTicksY(const AQDG_GRAPH_TICK_LIST *tickList, int lvl,
                                          int contentSize, double minValue, double maxValue);
 
+static void _drawCurveLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                            double minValueX, double maxValueX, double minValueY, double maxValueY,
+                            int pen);
+static void _drawCurvePoints(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                             double minValueX, double maxValueX, double minValueY, double maxValueY,
+                             int pen);
+static void _drawCurveStepLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                                double minValueX, double maxValueX, double minValueY, double maxValueY,
+                                int pen);
+
 
 
 /* ------------------------------------------------------------------------------------------------
@@ -185,6 +189,9 @@ void _drawCurve(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *c
   case AQDG_GRAPH_TYPE_POINTS:
     _drawCurvePoints(o, dc, curve, minValueX, maxValueX, minValueY, maxValueY, pen);
     break;
+  case AQDG_GRAPH_TYPE_STEPLINE:
+    _drawCurveStepLines(o, dc, curve, minValueX, maxValueX, minValueY, maxValueY, pen);
+    break;
   case AQDG_GRAPH_TYPE_BARS:
   default:
     break;
@@ -193,87 +200,6 @@ void _drawCurve(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *c
 
 
 
-void _drawCurveLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
-                     double minValueX, double maxValueX, double minValueY, double maxValueY,
-                     int pen)
-{
-  int width;
-  int height;
-  const AQDG_GRAPH_DATAPAIR_LIST *dpList;
-  const AQDG_GRAPH_DATAPAIR *dp;
-  int absX;
-  int absY;
-  int lastX=-1;
-  int lastY=-1;
-
-  absX=AQDG_Object_GetAbsoluteX(o);
-  absY=AQDG_Object_GetAbsoluteY(o);
-  width=AQDG_Object_GetWidth(o);
-  height=AQDG_Object_GetHeight(o);
-  dpList=AQDG_Graph_Curve_GetDataPairs(curve);
-  dp=dpList?AQDG_Graph_DataPair_List_First(dpList):NULL;
-  while(dp) {
-    int xPos;
-    int yPos;
-    double xValue;
-    double yValue;
-
-    xValue=AQDG_Graph_DataPair_GetValueX(dp);
-    yValue=AQDG_Graph_DataPair_GetValueY(dp);
-
-    xPos=_calcHorizontalPos(xValue, width, minValueX, maxValueX);
-    yPos=_calcVerticalPos(yValue, height, minValueY, maxValueY);
-    if (lastX>=0 && lastY>=0)
-      AQDG_Draw_Context_DrawLine(dc, pen, absX+lastX, absY+lastY, absX+xPos, absY+yPos);
-    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos-2, absX+xPos+2, absY+yPos+2);
-    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos+2, absX+xPos+2, absY+yPos-2);
-    lastX=xPos;
-    lastY=yPos;
-    dp=AQDG_Graph_DataPair_List_Next(dp);
-  }
-}
-
-
-
-void _drawCurvePoints(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
-                      double minValueX, double maxValueX, double minValueY, double maxValueY,
-                      int pen)
-{
-  int width;
-  int height;
-  const AQDG_GRAPH_DATAPAIR_LIST *dpList;
-  const AQDG_GRAPH_DATAPAIR *dp;
-  int absX;
-  int absY;
-
-  absX=AQDG_Object_GetAbsoluteX(o);
-  absY=AQDG_Object_GetAbsoluteY(o);
-  width=AQDG_Object_GetWidth(o);
-  height=AQDG_Object_GetHeight(o);
-  dpList=AQDG_Graph_Curve_GetDataPairs(curve);
-  dp=dpList?AQDG_Graph_DataPair_List_First(dpList):NULL;
-  while(dp) {
-    int xPos;
-    int yPos;
-    double xValue;
-    double yValue;
-
-    xValue=AQDG_Graph_DataPair_GetValueX(dp);
-    yValue=AQDG_Graph_DataPair_GetValueY(dp);
-
-    xPos=_calcHorizontalPos(xValue, width, minValueX, maxValueX);
-    yPos=_calcVerticalPos(yValue, height, minValueY, maxValueY);
-    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-4, absY+yPos-4, absX+xPos+4, absY+yPos+4);
-    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-4, absY+yPos+4, absX+xPos+4, absY+yPos-4);
-    dp=AQDG_Graph_DataPair_List_Next(dp);
-  }
-}
-
-
-
-
-
-
 void _drawVerticalGrid(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc)
 {
   AQDG_WIDGET_VIEWPORT *xo;
@@ -418,3 +344,138 @@ int _screenDistBetweenLevelTicksY(const AQDG_GRAPH_TICK_LIST *tickList, int lvl,
 
 
 
+
+
+
+/* ------------------------------------------------------------------------------------------------
+ * graph drawing
+ * ------------------------------------------------------------------------------------------------
+ */
+
+
+
+void _drawCurveLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                     double minValueX, double maxValueX, double minValueY, double maxValueY,
+                     int pen)
+{
+  int width;
+  int height;
+  const AQDG_GRAPH_DATAPAIR_LIST *dpList;
+  const AQDG_GRAPH_DATAPAIR *dp;
+  int absX;
+  int absY;
+  int lastX=-1;
+  int lastY=-1;
+
+  absX=AQDG_Object_GetAbsoluteX(o);
+  absY=AQDG_Object_GetAbsoluteY(o);
+  width=AQDG_Object_GetWidth(o);
+  height=AQDG_Object_GetHeight(o);
+  dpList=AQDG_Graph_Curve_GetDataPairs(curve);
+  dp=dpList?AQDG_Graph_DataPair_List_First(dpList):NULL;
+  while(dp) {
+    int xPos;
+    int yPos;
+    double xValue;
+    double yValue;
+
+    xValue=AQDG_Graph_DataPair_GetValueX(dp);
+    yValue=AQDG_Graph_DataPair_GetValueY(dp);
+
+    xPos=_calcHorizontalPos(xValue, width, minValueX, maxValueX);
+    yPos=_calcVerticalPos(yValue, height, minValueY, maxValueY);
+    if (lastX>=0 && lastY>=0)
+      AQDG_Draw_Context_DrawLine(dc, pen, absX+lastX, absY+lastY, absX+xPos, absY+yPos);
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos-2, absX+xPos+2, absY+yPos+2);
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos+2, absX+xPos+2, absY+yPos-2);
+    lastX=xPos;
+    lastY=yPos;
+    dp=AQDG_Graph_DataPair_List_Next(dp);
+  }
+}
+
+
+
+void _drawCurvePoints(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                      double minValueX, double maxValueX, double minValueY, double maxValueY,
+                      int pen)
+{
+  int width;
+  int height;
+  const AQDG_GRAPH_DATAPAIR_LIST *dpList;
+  const AQDG_GRAPH_DATAPAIR *dp;
+  int absX;
+  int absY;
+
+  absX=AQDG_Object_GetAbsoluteX(o);
+  absY=AQDG_Object_GetAbsoluteY(o);
+  width=AQDG_Object_GetWidth(o);
+  height=AQDG_Object_GetHeight(o);
+  dpList=AQDG_Graph_Curve_GetDataPairs(curve);
+  dp=dpList?AQDG_Graph_DataPair_List_First(dpList):NULL;
+  while(dp) {
+    int xPos;
+    int yPos;
+    double xValue;
+    double yValue;
+
+    xValue=AQDG_Graph_DataPair_GetValueX(dp);
+    yValue=AQDG_Graph_DataPair_GetValueY(dp);
+
+    xPos=_calcHorizontalPos(xValue, width, minValueX, maxValueX);
+    yPos=_calcVerticalPos(yValue, height, minValueY, maxValueY);
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-4, absY+yPos-4, absX+xPos+4, absY+yPos+4);
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-4, absY+yPos+4, absX+xPos+4, absY+yPos-4);
+    dp=AQDG_Graph_DataPair_List_Next(dp);
+  }
+}
+
+
+
+void _drawCurveStepLines(AQDG_OBJECT *o, AQDG_DRAW_CONTEXT *dc, const AQDG_GRAPH_CURVE *curve,
+                         double minValueX, double maxValueX, double minValueY, double maxValueY,
+                         int pen)
+{
+  int width;
+  int height;
+  const AQDG_GRAPH_DATAPAIR_LIST *dpList;
+  const AQDG_GRAPH_DATAPAIR *dp;
+  int absX;
+  int absY;
+  int lastX=-1;
+  int lastY=-1;
+
+  absX=AQDG_Object_GetAbsoluteX(o);
+  absY=AQDG_Object_GetAbsoluteY(o);
+  width=AQDG_Object_GetWidth(o);
+  height=AQDG_Object_GetHeight(o);
+  dpList=AQDG_Graph_Curve_GetDataPairs(curve);
+  dp=dpList?AQDG_Graph_DataPair_List_First(dpList):NULL;
+  while(dp) {
+    int xPos;
+    int yPos;
+    double xValue;
+    double yValue;
+
+    xValue=AQDG_Graph_DataPair_GetValueX(dp);
+    yValue=AQDG_Graph_DataPair_GetValueY(dp);
+
+    xPos=_calcHorizontalPos(xValue, width, minValueX, maxValueX);
+    yPos=_calcVerticalPos(yValue, height, minValueY, maxValueY);
+    if (lastX>=0 && lastY>=0) {
+      AQDG_Draw_Context_DrawLine(dc, pen, absX+lastX, absY+lastY, absX+xPos, absY+lastY);
+      AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos, absY+lastY, absX+xPos, absY+yPos);
+    }
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos-2, absX+xPos+2, absY+yPos+2);
+    AQDG_Draw_Context_DrawLine(dc, pen, absX+xPos-2, absY+yPos+2, absX+xPos+2, absY+yPos-2);
+    lastX=xPos;
+    lastY=yPos;
+    dp=AQDG_Graph_DataPair_List_Next(dp);
+  }
+}
+
+
+
+
+
+