[FEATURE]: Add a color ramp class which generates random colors on-the-fly

Author: mhugent

src/core/symbology-ng/qgsvectorcolorrampv2.cpp

@@ -319,6 +319,52 @@ void QgsVectorRandomColorRampV2::updateColors()
   }
 }
 
+/////////////
+
+QgsRandomColorsV2::QgsRandomColorsV2()
+{
+  srand( QTime::currentTime().msec() );
+}
+
+QgsRandomColorsV2::~QgsRandomColorsV2()
+{
+
+}
+
+int QgsRandomColorsV2::count() const
+{
+  return INT_MAX;
+}
+
+double QgsRandomColorsV2::value( int index ) const
+{
+  Q_UNUSED( index );
+  return 0.0;
+}
+
+QColor QgsRandomColorsV2::color( double value ) const
+{
+  Q_UNUSED( value );
+  int r = 1 + ( int )( 255.0 * rand() / ( RAND_MAX + 1.0 ) );
+  int g = 1 + ( int )( 255.0 * rand() / ( RAND_MAX + 1.0 ) );
+  int b = 1 + ( int )( 255.0 * rand() / ( RAND_MAX + 1.0 ) );
+  return QColor( r, g, b );
+}
+
+QString QgsRandomColorsV2::type() const
+{
+  return "randomcolors";
+}
+
+QgsVectorColorRampV2* QgsRandomColorsV2::clone() const
+{
+  return new QgsRandomColorsV2();
+}
+
+QgsStringMap QgsRandomColorsV2::properties() const
+{
+  return QgsStringMap();
+}
 
 ////////////
 

src/core/symbology-ng/qgsvectorcolorrampv2.h

@@ -155,6 +155,25 @@ class CORE_EXPORT QgsVectorRandomColorRampV2 : public QgsVectorColorRampV2
     QList<QColor> mColors;
 };
 
+class CORE_EXPORT QgsRandomColorsV2: public QgsVectorColorRampV2
+{
+  public:
+    QgsRandomColorsV2();
+    ~QgsRandomColorsV2();
+
+    int count() const;
+
+    double value( int index ) const;
+
+    QColor color( double value ) const;
+
+    QString type() const;
+
+    QgsVectorColorRampV2* clone() const;
+
+    QgsStringMap properties() const;
+};
+
 
 #define DEFAULT_COLORBREWER_SCHEMENAME "Spectral"
 #define DEFAULT_COLORBREWER_COLORS     5

src/gui/symbology-ng/qgscategorizedsymbolrendererv2widget.cpp

@@ -371,6 +371,11 @@ QgsCategorizedSymbolRendererV2Widget::QgsCategorizedSymbolRendererV2Widget( QgsV
   populateColumns();
 
   cboCategorizedColorRamp->populate( mStyle );
+  int randomIndex = cboCategorizedColorRamp->findText( tr( "Random colors" ) );
+  if ( randomIndex != -1 )
+  {
+    cboCategorizedColorRamp->setCurrentIndex( randomIndex );
+  }
 
   // set project default color ramp
   QString defaultColorRamp = QgsProject::instance()->readEntry( "DefaultStyles", "/ColorRamp", "" );

src/gui/symbology-ng/qgscolorrampcombobox.cpp

@@ -54,14 +54,20 @@ void QgsColorRampComboBox::populate( QgsStyleV2* style )
     delete ramp;
   }
 
+  addItem( tr( "Random colors" ) );
   addItem( tr( "New color ramp..." ) );
   connect( this, SIGNAL( activated( int ) ), SLOT( colorRampChanged( int ) ) );
 }
 
 QgsVectorColorRampV2* QgsColorRampComboBox::currentColorRamp()
 {
   QString rampName = currentText();
-  if ( rampName == "[source]" && mSourceColorRamp )
+
+  if ( rampName == tr( "Random colors" ) )
+  {
+    return new QgsRandomColorsV2();
+  }
+  else if ( rampName == "[source]" && mSourceColorRamp )
     return mSourceColorRamp->clone();
   else
     return mStyle->colorRamp( rampName );

src/gui/symbology-ng/qgsgraduatedsymbolrendererv2widget.cpp

@@ -635,7 +635,6 @@ QgsRangeList QgsGraduatedSymbolRendererV2Widget::selectedRanges()
   QModelIndexList selectedRows = viewGraduated->selectionModel()->selectedRows();
   QModelIndexList::const_iterator sIt = selectedRows.constBegin();
 
-  const QgsRangeList& ranges = mRenderer->ranges();
   for ( ; sIt != selectedRows.constEnd(); ++sIt )
   {
     selectedRanges.append( mModel->rendererRange( *sIt ) );