Merge pull request #3489 from nyalldawson/preset_color_ramp

[FEATURE] "Preset colors" color ramp

python/core/qgscolorramp.sip

@@ -16,6 +16,8 @@ class QgsColorRamp
     sipType = sipType_QgsLimitedRandomColorRamp;
   else if (sipCpp->type() == "randomcolors")
     sipType = sipType_QgsRandomColorRamp;
+  else if (sipCpp->type() == "preset")
+    sipType = sipType_QgsPresetSchemeColorRamp;
   else if (sipCpp->type() == "colorbrewer")
     sipType = sipType_QgsColorBrewerColorRamp;
   else if (sipCpp->type() == "cpt-city")
@@ -285,6 +287,64 @@ class QgsRandomColorRamp : QgsColorRamp
     QgsStringMap properties() const;
 };
 
+/** \ingroup core
+ * \class QgsPresetSchemeColorRamp
+ * \brief A scheme based color ramp consisting of a list of predefined colors.
+ * \note added in QGIS 3.0
+ */
+class QgsPresetSchemeColorRamp : QgsColorRamp, QgsColorScheme
+{
+%TypeHeaderCode
+#include <qgscolorramp.h>
+%End
+
+  public:
+
+    /** Constructor for QgsPresetSchemeColorRamp.
+     * @param colors list of colors in ramp
+     */
+    QgsPresetSchemeColorRamp( const QList< QColor >& colors = QList< QColor >() );
+
+    /** Constructor for QgsPresetColorRamp.
+     * @param colors list of named colors in ramp
+     * @note not available in Python bindings - use setColors instead
+     */
+    //QgsPresetSchemeColorRamp( const QgsNamedColorList& colors );
+
+    /** Returns a new QgsPresetSchemeColorRamp color ramp created using the properties encoded in a string
+     * map.
+     * @param properties color ramp properties
+     * @see properties()
+     */
+    static QgsColorRamp* create( const QgsStringMap& properties = QgsStringMap() );
+
+    /** Sets the list of colors used by the ramp.
+     * @param colors list of colors
+     * @see colors()
+     */
+    bool setColors( const QgsNamedColorList& colors, const QString& = QString(), const QColor& = QColor() );
+
+    /** Returns the list of colors used by the ramp.
+     * @see setColors()
+     */
+    QList< QColor > colors() const;
+
+    // QgsColorRamp interface
+    virtual double value( int index ) const;
+    virtual QColor color( double value ) const;
+    virtual QString type() const;
+    virtual QgsPresetSchemeColorRamp* clone() const /Factory/;
+    virtual QgsStringMap properties() const;
+    int count() const;
+
+    // QgsColorScheme interface
+    QString schemeName() const;
+    QgsNamedColorList fetchColors( const QString &context = QString(),
+                                   const QColor &baseColor = QColor() );
+    bool isEditable() const;
+
+};
+
 /** \ingroup core
  * \class QgsColorBrewerColorRamp
  */

python/gui/gui.sip

@@ -141,6 +141,7 @@
 %Include qgspanelwidgetstack.sip
 %Include qgspixmaplabel.sip
 %Include qgspluginmanagerinterface.sip
+%Include qgspresetcolorrampdialog.sip
 %Include qgsprevieweffect.sip
 %Include qgsprojectbadlayerguihandler.sip
 %Include qgsprojectionselectionwidget.sip

python/gui/qgscolorschemelist.sip

@@ -85,8 +85,9 @@ class QgsColorSchemeModel: QAbstractItemModel
     /** Add a color to the list
      * @param color color to add
      * @param label label for color
+     * @param allowDuplicate set to true to allow duplicate colors to be added (colors which are already present in the list)
      */
-    void addColor( const QColor color, const QString &label = QString() );
+    void addColor( const QColor &color, const QString &label = QString(), bool allowDuplicate = false );
 
     /** Returns whether the color scheme model has been modified
      * @returns true if colors have been modified
@@ -162,11 +163,12 @@ class QgsColorSchemeList: QTreeView
      */
     void removeSelection();
 
-    /** Adds a color to the list
+    /** Add a color to the list
      * @param color color to add
-     * @param label optional label for color
+     * @param label label for color
+     * @param allowDuplicate set to true to allow duplicate colors to be added (colors which are already present in the list)
      */
-    void addColor( const QColor &color, const QString &label = QString() );
+    void addColor( const QColor &color, const QString &label = QString(), bool allowDuplicate = false );
 
     /** Pastes colors from clipboard to the list
      * @see copyColors

python/gui/qgscompoundcolorwidget.sip

@@ -41,6 +41,13 @@ class QgsCompoundColorWidget : QgsPanelWidget
      */
     void setAllowAlpha( const bool allowAlpha );
 
+    /** Sets whether the widget's color has been "discarded" and the selected color should not
+     * be stored in the recent color list.
+     * @param discarded set to true to avoid adding color to recent color list on widget destruction.
+     * @note added in QGIS 3.0
+     */
+    void setDiscarded( bool discarded );
+
   signals:
 
     /** Emitted when the dialog's color changes

python/gui/qgspresetcolorrampdialog.sip

@@ -0,0 +1,75 @@
+/** \ingroup gui
+ * \class QgsPresetColorRampWidget
+ * A widget which allows users to modify the properties of a QgsPresetSchemeColorRamp.
+ * \note added in QGIS 3.0
+ */
+
+class QgsPresetColorRampWidget : QgsPanelWidget
+{
+%TypeHeaderCode
+#include <qgspresetcolorrampdialog.h>
+%End
+
+  public:
+
+/** Constructor for QgsPresetColorRampWidget.
+     * @param ramp initial ramp to show in dialog
+     * @param parent parent widget
+     */
+    QgsPresetColorRampWidget( const QgsPresetSchemeColorRamp& ramp, QWidget* parent /TransferThis/ = nullptr );
+
+    ~QgsPresetColorRampWidget();
+
+    /** Returns a color ramp representing the current settings from the dialog.
+     * @see setRamp()
+     */
+    QgsPresetSchemeColorRamp ramp() const;
+
+    /** Sets the color ramp to show in the dialog.
+     * @param ramp color ramp
+     * @see ramp()
+     */
+    void setRamp( const QgsPresetSchemeColorRamp& ramp );
+
+  signals:
+
+    //! Emitted when the dialog settings change
+    void changed();
+};
+
+/** \ingroup gui
+ * \class QgsPresetColorRampDialog
+ * A dialog which allows users to modify the properties of a QgsPresetSchemeColorRamp.
+ * \note added in QGIS 3.0
+ */
+
+class QgsPresetColorRampDialog : QDialog
+{
+%TypeHeaderCode
+#include <qgspresetcolorrampdialog.h>
+%End
+
+  public:
+
+    /** Constructor for QgsPresetColorRampDialog.
+     * @param ramp initial ramp to show in dialog
+     * @param parent parent widget
+     */
+    QgsPresetColorRampDialog( const QgsPresetSchemeColorRamp& ramp, QWidget* parent /TransferThis/ = nullptr );
+
+    /** Returns a color ramp representing the current settings from the dialog.
+     * @see setRamp()
+     */
+    QgsPresetSchemeColorRamp ramp() const;
+
+    /** Sets the color ramp to show in the dialog.
+     * @param ramp color ramp
+     * @see ramp()
+     */
+    void setRamp( const QgsPresetSchemeColorRamp& ramp );
+
+  signals:
+
+    //! Emitted when the dialog settings change
+    void changed();
+};

src/core/qgscolorramp.cpp

@@ -738,3 +738,102 @@ bool QgsCptCityColorRamp::loadFile()
   mFileLoaded = true;
   return true;
 }
+
+
+//
+// QgsPresetColorRamp
+//
+
+QgsPresetSchemeColorRamp::QgsPresetSchemeColorRamp( const QList<QColor>& colors )
+{
+  Q_FOREACH ( const QColor& color, colors )
+  {
+    mColors << qMakePair( color, color.name() );
+  }
+  // need at least one color
+  if ( mColors.isEmpty() )
+    mColors << qMakePair( QColor( 250, 75, 60 ), QString( "#fa4b3c" ) );
+}
+
+QgsPresetSchemeColorRamp::QgsPresetSchemeColorRamp( const QgsNamedColorList& colors )
+    : mColors( colors )
+{
+  // need at least one color
+  if ( mColors.isEmpty() )
+    mColors << qMakePair( QColor( 250, 75, 60 ), QString( "#fa4b3c" ) );
+}
+
+QgsColorRamp* QgsPresetSchemeColorRamp::create( const QgsStringMap& properties )
+{
+  QgsNamedColorList colors;
+
+  int i = 0;
+  QString colorString = properties.value( QString( "preset_color_%1" ).arg( i ), QString() );
+  QString colorName = properties.value( QString( "preset_color_name_%1" ).arg( i ), QString() );
+  while ( !colorString.isEmpty() )
+  {
+    colors << qMakePair( QgsSymbolLayerUtils::decodeColor( colorString ), colorName );
+    i++;
+    colorString = properties.value( QString( "preset_color_%1" ).arg( i ), QString() );
+    colorName = properties.value( QString( "preset_color_name_%1" ).arg( i ), QString() );
+  }
+
+  return new QgsPresetSchemeColorRamp( colors );
+}
+
+QList<QColor> QgsPresetSchemeColorRamp::colors() const
+{
+  QList< QColor > l;
+  for ( int i = 0; i < mColors.count(); ++i )
+  {
+    l << mColors.at( i ).first;
+  }
+  return l;
+}
+
+double QgsPresetSchemeColorRamp::value( int index ) const
+{
+  if ( mColors.size() < 1 )
+    return 0;
+  return static_cast< double >( index ) / ( mColors.size() - 1 );
+}
+
+QColor QgsPresetSchemeColorRamp::color( double value ) const
+{
+  if ( value < 0 || value > 1 )
+    return QColor();
+
+  int colorCnt = mColors.count();
+  int colorIdx = qMin( static_cast< int >( value * colorCnt ), colorCnt - 1 );
+
+  if ( colorIdx >= 0 && colorIdx < colorCnt )
+    return mColors.at( colorIdx ).first;
+
+  return QColor();
+}
+
+QgsPresetSchemeColorRamp* QgsPresetSchemeColorRamp::clone() const
+{
+  return new QgsPresetSchemeColorRamp( *this );
+}
+
+QgsStringMap QgsPresetSchemeColorRamp::properties() const
+{
+  QgsStringMap props;
+  for ( int i = 0; i < mColors.count(); ++i )
+  {
+    props.insert( QString( "preset_color_%1" ).arg( i ), QgsSymbolLayerUtils::encodeColor( mColors.at( i ).first ) );
+    props.insert( QString( "preset_color_name_%1" ).arg( i ), mColors.at( i ).second );
+  }
+  return props;
+}
+
+int QgsPresetSchemeColorRamp::count() const
+{
+  return mColors.count();
+}
+
+QgsNamedColorList QgsPresetSchemeColorRamp::fetchColors( const QString& , const QColor& )
+{
+  return mColors;
+}

src/core/qgscolorramp.h

@@ -19,6 +19,7 @@
 #include <QColor>
 #include <QGradient>
 #include "qgis.h"
+#include "qgscolorscheme.h"
 
 /** \ingroup core
  * \class QgsColorRamp
@@ -381,6 +382,64 @@ class CORE_EXPORT QgsRandomColorRamp: public QgsColorRamp
 };
 
 
+/** \ingroup core
+ * \class QgsPresetSchemeColorRamp
+ * \brief A scheme based color ramp consisting of a list of predefined colors.
+ * \note added in QGIS 3.0
+ */
+class CORE_EXPORT QgsPresetSchemeColorRamp : public QgsColorRamp, public QgsColorScheme
+{
+  public:
+
+    /** Constructor for QgsPresetSchemeColorRamp.
+     * @param colors list of colors in ramp
+     */
+    QgsPresetSchemeColorRamp( const QList< QColor >& colors = QList< QColor >() );
+
+    /** Constructor for QgsPresetColorRamp.
+     * @param colors list of named colors in ramp
+     * @note not available in Python bindings - use setColors instead
+     */
+    QgsPresetSchemeColorRamp( const QgsNamedColorList& colors );
+
+    /** Returns a new QgsPresetSchemeColorRamp color ramp created using the properties encoded in a string
+     * map.
+     * @param properties color ramp properties
+     * @see properties()
+     */
+    static QgsColorRamp* create( const QgsStringMap& properties = QgsStringMap() );
+
+    /** Sets the list of colors used by the ramp.
+     * @param colors list of colors
+     * @see colors()
+     */
+    bool setColors( const QgsNamedColorList& colors, const QString& = QString(), const QColor& = QColor() ) override { mColors = colors; return true; }
+
+    /** Returns the list of colors used by the ramp.
+     * @see setColors()
+     */
+    QList< QColor > colors() const;
+
+    // QgsColorRamp interface
+    virtual double value( int index ) const override;
+    virtual QColor color( double value ) const override;
+    virtual QString type() const override { return "preset"; }
+    virtual QgsPresetSchemeColorRamp* clone() const override;
+    virtual QgsStringMap properties() const override;
+    int count() const override;
+
+    // QgsColorScheme interface
+    QString schemeName() const override { return "preset"; }
+    QgsNamedColorList fetchColors( const QString &context = QString(),
+                                   const QColor &baseColor = QColor() ) override;
+    bool isEditable() const override { return true; }
+
+  private:
+
+    QgsNamedColorList mColors;
+};
+
+
 #define DEFAULT_COLORBREWER_SCHEMENAME "Spectral"
 #define DEFAULT_COLORBREWER_COLORS     5
 

src/core/symbology-ng/qgssymbollayerutils.cpp

@@ -2665,6 +2665,8 @@ QgsColorRamp* QgsSymbolLayerUtils::loadColorRamp( QDomElement& element )
     return QgsColorBrewerColorRamp::create( props );
   else if ( rampType == "cpt-city" )
     return QgsCptCityColorRamp::create( props );
+  else if ( rampType == "preset" )
+    return QgsPresetSchemeColorRamp::create( props );
   else
   {
     QgsDebugMsg( "unknown colorramp type " + rampType );

src/gui/CMakeLists.txt

@@ -281,6 +281,7 @@ SET(QGIS_GUI_SRCS
   qgspanelwidgetstack.cpp
   qgspixmaplabel.cpp
   qgspluginmanagerinterface.cpp
+  qgspresetcolorrampdialog.cpp
   qgsprevieweffect.cpp
   qgsprojectbadlayerguihandler.cpp
   qgsprojectionselectionwidget.cpp
@@ -437,6 +438,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgspanelwidgetstack.h
   qgspixmaplabel.h
   qgspluginmanagerinterface.h
+  qgspresetcolorrampdialog.h
   qgsprevieweffect.h
   qgsprojectbadlayerguihandler.h
   qgsprojectionselectionwidget.h