[chronojump] JumpsDjOptimalFall manage ok when there are no jumps or < 3

[Xavier de Blas <xaviblas src gnome org>]

commit ae495eb4b44ec7329ceaf369dc6a5c38303e3cd6
Author: Xavier de Blas <xaviblas gmail com>
Date:   Fri Dec 27 13:04:59 2019 +0100

    JumpsDjOptimalFall manage ok when there are no jumps or < 3

 src/gui/app1/chronojumpJumpsDjOptimalFall.cs |  9 +++-
 src/gui/jumpsDjOptimalFall.cs                | 65 +++++++++++++++++++---------
 2 files changed, 51 insertions(+), 23 deletions(-)
---
diff --git a/src/gui/app1/chronojumpJumpsDjOptimalFall.cs b/src/gui/app1/chronojumpJumpsDjOptimalFall.cs
index 099cf85c..afbcc40f 100644
--- a/src/gui/app1/chronojumpJumpsDjOptimalFall.cs
+++ b/src/gui/app1/chronojumpJumpsDjOptimalFall.cs
@@ -45,8 +45,14 @@ public partial class ChronoJumpWindow
                if(calculateData)
                        jumpsDjOptimalFall.Calculate(currentPerson.UniqueID, currentSession.UniqueID);
 
-               if(jumpsDjOptimalFall.Point_l.Count > 0)
+               if(jumpsDjOptimalFall.Point_l.Count == 0)
                {
+                       //constructor for showing blank screen with a message
+                       new JumpsDjOptimalFallGraph(
+                                       drawingarea_jumps_dj_optimal_fall,
+                                       currentPerson.Name, currentSession.DateShort);
+               } else {
+                       //regular constructor
                        JumpsDjOptimalFallGraph jdofg = new JumpsDjOptimalFallGraph(
                                        jumpsDjOptimalFall.Point_l,
                                        jumpsDjOptimalFall.Coefs,
@@ -56,7 +62,6 @@ public partial class ChronoJumpWindow
                                        currentPerson.Name, currentSession.DateShort);
                        jdofg.Do();
                }
-               //TODO: if not, just blank screen
        }
        private void on_drawingarea_jumps_dj_optimal_fall_expose_event (object o, ExposeEventArgs args) 
        {
diff --git a/src/gui/jumpsDjOptimalFall.cs b/src/gui/jumpsDjOptimalFall.cs
index 1ec68421..1c51bda7 100644
--- a/src/gui/jumpsDjOptimalFall.cs
+++ b/src/gui/jumpsDjOptimalFall.cs
@@ -52,6 +52,20 @@ public class JumpsDjOptimalFallGraph
        const int totalMargins = outerMargins + innerMargins;
        const int textHeight = 12;
 
+       //constructor when there are no points
+       public JumpsDjOptimalFallGraph (DrawingArea area, string title, string date)
+       {
+               this.area = area;
+
+               initGraph();
+
+               g.SetFontSize(16);
+               printText(area.Allocation.Width /2, area.Allocation.Height /2, 24, textHeight, "Need to 
execute jumps", g, true);
+
+               endGraph();
+       }
+
+       //regular constructor
        public JumpsDjOptimalFallGraph (List<Point> point_l, double[] coefs, double xAtMMaxY, //x at Model 
MaxY
                        double pointsMaxValue, DrawingArea area, string title, string date)
        {
@@ -69,13 +83,17 @@ public class JumpsDjOptimalFallGraph
                LogB.Information("at JumpsDjOptimalFallGraph.Do");
                initGraph();
 
+               findMaximums();
+               paintAxisAndGrid();
+
                LogB.Information(string.Format("coef length:{0}", coefs.Length));
                if(coefs.Length == 3)
-               {
-                       findMaximums();
-                       paintAxisAndGrid();
                        plotPredictedLine();
-                       plotRealPoints();
+
+               plotRealPoints();
+
+               if(coefs.Length == 3)
+               {
                        plotPredictedMaxPoint();
                        writeText();
                }
@@ -102,25 +120,12 @@ public class JumpsDjOptimalFallGraph
                g.SelectFontFace("Helvetica", Cairo.FontSlant.Normal, Cairo.FontWeight.Normal);
                g.SetFontSize(textHeight);
 
-               if(pointsMaxValue == 0)
-               {
-                       g.SetSourceRGB(0,0,0);
-                       g.SetFontSize(16);
-                       printText(100, 100, 24, textHeight, "need points", g, false);
-                       g.GetTarget().Dispose ();
-                       g.Dispose ();
-                       return;
-               }
-
                red = colorFromRGB(200,0,0);
                blue = colorFromRGB(178, 223, 238); //lightblue
        }
 
        private void findMaximums()
        {
-               //double xgraph = 0;
-               //double ygraph = 0;
-
                foreach(Point p in point_l)
                {
                        if(p.X < minX)
@@ -133,9 +138,25 @@ public class JumpsDjOptimalFallGraph
                                maxY = p.Y;
                }
 
-               yAtMMaxY = coefs[0] + coefs[1]*xAtMMaxY + coefs[2]*Math.Pow(xAtMMaxY,2);
-               absoluteMaxY = yAtMMaxY;
-               if(maxY > absoluteMaxY)
+               //if there is only one point, or by any reason mins == maxs, have mins and maxs separated
+               if(minX == maxX)
+               {
+                       minX -= .5 * minX;
+                       maxX += .5 * maxX;
+               }
+               if(minY == maxY)
+               {
+                       minY -= .5 * minY;
+                       maxY += .5 * maxY;
+               }
+
+               if(coefs.Length == 3)
+               {
+                       yAtMMaxY = coefs[0] + coefs[1]*xAtMMaxY + coefs[2]*Math.Pow(xAtMMaxY,2);
+                       absoluteMaxY = yAtMMaxY;
+                       if(maxY > absoluteMaxY)
+                               absoluteMaxY = maxY;
+               } else
                        absoluteMaxY = maxY;
        }
 
@@ -193,12 +214,14 @@ public class JumpsDjOptimalFallGraph
        {
                foreach(Point p in point_l)
                {
+                       //LogB.Information(string.Format("point: {0}", p));
                        double xgraph = calculatePaintX(
                                        ( p.X ),
                                        graphWidth, maxX, minX, totalMargins, totalMargins);
                        double ygraph = calculatePaintY(
                                        ( p.Y ),
                                        graphHeight, absoluteMaxY, minY, totalMargins, totalMargins);
+                       LogB.Information(string.Format("{0}, {1}", xgraph, ygraph));
                        g.MoveTo(xgraph+6, ygraph);
                        g.Arc(xgraph, ygraph, 6.0, 0.0, 2.0 * Math.PI); //full circle
                        g.Color = blue;
@@ -248,13 +271,13 @@ public class JumpsDjOptimalFallGraph
 
        private void endGraph()
        {
-               //dispose
                g.GetTarget().Dispose ();
                g.Dispose ();
        }
 
        private void paintCairoGrid (double min, double max, int seps, bool horiz)
        {
+               LogB.Information(string.Format("paintCairoGrid: {0}, {1}, {2}, {3}", min, max, seps, horiz));
                //show 5 steps positive, 5 negative (if possible)
                int temp = Convert.ToInt32(Util.DivideSafe(max - min, seps));
                int step = temp;