Re 5058, Added display of color scale

A simple band of colors is used to display the
color scale in use, with zero at the center of
the display, colors for negative values to the left
and colors for positive values to the right.
refs #5058

Code/Mantid/MantidQt/ImageViewer/inc/MantidQtImageViewer/IVConnections.h

@@ -68,6 +68,10 @@ public:
 
   ~IVConnections();
 
+  /// Set the pix map that shows the color scale from the specified color maps
+  void ShowColorScale( std::vector<QRgb> & positive_color_table,
+                       std::vector<QRgb> & negative_color_table );
+
 public slots:
   void close_viewer();
   void toggle_Hscroll();

Code/Mantid/MantidQt/ImageViewer/inc/MantidQtImageViewer/ImageView.ui

@@ -139,7 +139,7 @@
          </widget>
         </item>
         <item row="4" column="0">
-         <widget class="QWidget" name="color_scale" native="true"/>
+         <widget class="QLabel" name="color_scale" native="true"/>
         </item>
         <item row="5" column="0">
          <widget class="QLabel" name="table_label">

Code/Mantid/MantidQt/ImageViewer/src/IVConnections.cpp

@@ -41,7 +41,6 @@ IVConnections::IVConnections( Ui_MainWindow* ui,
   iv_ui->actionOffset_Diagonally->setDisabled(true);
   iv_ui->actionGraph_Rebinned_Data->setDisabled(true);
   iv_ui->menuHelp->setDisabled(true);
-  iv_ui->label_2->setDisabled(true);
  
   this->iv_main_window = iv_main_window;
   QObject::connect( iv_ui->actionClose, SIGNAL(triggered()),
@@ -180,6 +179,19 @@ IVConnections::IVConnections( Ui_MainWindow* ui,
   iv_ui->actionOptimal->setCheckable(true);
   iv_ui->actionMulti->setCheckable(true);
   iv_ui->actionSpectrum->setCheckable(true);
+                                                    // set up initial color
+                                                    // scale display
+  iv_ui->color_scale->setScaledContents(true);
+  iv_ui->color_scale->setMinimumHeight(15);
+  iv_ui->color_scale->setMinimumWidth(15);
+  std::vector<QRgb> positive_color_table;
+  ColorMaps::GetColorMap( ColorMaps::HEAT, 256, positive_color_table );
+
+  std::vector<QRgb> negative_color_table;
+  ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
+
+  ShowColorScale( positive_color_table, negative_color_table );
+
 
   color_group = new QActionGroup(this);
   color_group->addAction(iv_ui->actionHeat);
@@ -369,6 +381,7 @@ void IVConnections::heat_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::gray_color_scale()
@@ -380,6 +393,7 @@ void IVConnections::gray_color_scale()
   ColorMaps::GetColorMap( ColorMaps::HEAT, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::negative_gray_color_scale()
@@ -391,6 +405,7 @@ void IVConnections::negative_gray_color_scale()
   ColorMaps::GetColorMap( ColorMaps::HEAT, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::green_yellow_color_scale()
@@ -402,6 +417,7 @@ void IVConnections::green_yellow_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::rainbow_color_scale()
@@ -413,6 +429,7 @@ void IVConnections::rainbow_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::optimal_color_scale()
@@ -424,6 +441,7 @@ void IVConnections::optimal_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::multi_color_scale()
@@ -435,6 +453,7 @@ void IVConnections::multi_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
 }
 
 void IVConnections::spectrum_color_scale()
@@ -446,6 +465,50 @@ void IVConnections::spectrum_color_scale()
   ColorMaps::GetColorMap( ColorMaps::GRAY, 256, negative_color_table );
 
   image_display->SetColorScales( positive_color_table, negative_color_table );
+  ShowColorScale( positive_color_table, negative_color_table );
+}
+
+
+/**
+ *  Set the pix map that shows the color scale from the specified positive
+ *  and negative color tables.
+ *
+ *  @param positive_color_table  The new color table used to map positive data 
+ *                               values to an RGB color.
+ *  @param negative_color_table  The new color table used to map negative data 
+ *                               values to an RGB color.  This must have the
+ *                               same number of entries as the positive
+ *                               color table.
+ */
+void IVConnections::ShowColorScale( std::vector<QRgb> & positive_color_table,
+                                    std::vector<QRgb> & negative_color_table )
+{
+  size_t total_colors = positive_color_table.size() + 
+                        negative_color_table.size();
+
+  unsigned int *rgb_data = new unsigned int[ total_colors ];
+
+  size_t index = 0;
+  size_t n_colors = negative_color_table.size();
+  for ( size_t i = 0; i < n_colors; i++ )
+  {
+    rgb_data[index] = negative_color_table[ n_colors - 1 - i ];
+    index++;
+  }
+
+  n_colors = positive_color_table.size();
+  for ( size_t i = 0; i < n_colors; i++ )
+  {
+    rgb_data[index] = positive_color_table[i];
+    index++;
+  }
+
+  uchar *buffer = (uchar*)rgb_data;
+  QImage image( buffer, (int)total_colors, 1, QImage::Format_RGB32 );
+  QPixmap pixmap = QPixmap::fromImage(image);
+  iv_ui->color_scale->setPixmap( pixmap );
+
+// delete[] rgb_data;
 }