Fixed simulation plot legend

eeschema/sim/sim_plot_panel.cpp

@@ -68,6 +68,7 @@ void SIM_PLOT_PANEL::AddTrace( const wxString& aName, int aPoints,
     TRACE trace;
 
     trace.name = aName;
+    trace.style = wxString( '-' ) + m_painter.GenerateColor( SIM_PLOT_PAINTER::DARK );
     trace.x.Set( aT, aPoints );
     trace.y.Set( aY, aPoints );
     m_traces.push_back( trace );
@@ -141,12 +142,54 @@ int SIM_PLOT_PAINTER::Draw( mglGraph* aGraph )
     // Draw traces
     for( auto t : traces )
     {
-        aGraph->AddLegend( (const char*) t.name.c_str(), "" );
-        aGraph->Plot( t.y, "-" );
+        aGraph->AddLegend( (const char*) t.name.c_str(), t.style );
+        aGraph->Plot( t.y, t.style );
     }
 
     if( traces.size() )
-        aGraph->Legend( 1, "-#" );
+        aGraph->Legend( 1, "-#" );  // legend entries horizontally + draw a box around legend
 
     return 0;
 }
+
+
+wxString SIM_PLOT_PAINTER::GenerateColor( COLOR_TYPE aType )
+{
+    const char colors[] = "rgbcmylenupq";
+    const unsigned int colorsNumber = sizeof( colors ) - 1;
+
+    // Safe defaults
+    char color = 'k';       // black
+    int shade = 5;
+
+    switch( aType )
+    {
+        case LIGHT:
+            color = colors[m_lightColorIdx % colorsNumber];
+            shade = 5 + m_lightColorIdx / colorsNumber;
+            ++m_lightColorIdx;
+
+            if( shade == 10 )
+            {
+                // Reached the color limit
+                shade = 5;
+                m_lightColorIdx = 0;
+            }
+            break;
+
+        case DARK:
+            color = toupper( colors[m_darkColorIdx % colorsNumber] );
+            shade = 5 - m_darkColorIdx / colorsNumber;
+            ++m_darkColorIdx;
+
+            if( shade == 0 )
+            {
+                // Reached the color limit
+                shade = 5;
+                m_darkColorIdx = 0;
+            }
+            break;
+    }
+
+    return wxString::Format( "{%c%d}", color, shade );
+}

eeschema/sim/sim_plot_panel.h

@@ -33,7 +33,7 @@ class SIM_PLOT_PAINTER : public mglDraw
 {
 public:
     SIM_PLOT_PAINTER( const SIM_PLOT_PANEL* aParent )
-        : m_parent( aParent )
+        : m_parent( aParent ), m_lightColorIdx( 0 ), m_darkColorIdx( 0 )
     {
     }
 
@@ -45,8 +45,14 @@ public:
 
     int Draw( mglGraph* aGraph ) override;
 
+    enum COLOR_TYPE { LIGHT, DARK };
+
+    ///> Generates a new, unique color for plotting curves
+    wxString GenerateColor( COLOR_TYPE aType );
+
 private:
     const SIM_PLOT_PANEL* m_parent;
+    int m_lightColorIdx, m_darkColorIdx;
 };
 
 
@@ -59,7 +65,7 @@ public:
     ~SIM_PLOT_PANEL();
 
     struct TRACE {
-        wxString name;
+        wxString name, style;
         mglData x, y;
     };