New blend modes combo box widget

src/gui/CMakeLists.txt

@@ -48,6 +48,7 @@ qgisinterface.cpp
 qgsannotationitem.cpp
 qgsattributeeditor.cpp
 qgslegendinterface.cpp
+qgsblendmodecombobox.cpp
 qgscharacterselectdialog.cpp
 qgscolorbutton.cpp
 qgscomposerview.cpp
@@ -153,6 +154,7 @@ attributetable/qgsattributetablememorymodel.h
 attributetable/qgsattributetabledelegate.h
 
 qgsattributeeditor.h
+qgsblendmodecombobox.h
 qgscharacterselectdialog.h
 qgscomposerview.h
 qgsdetaileditemdelegate.h
@@ -227,6 +229,7 @@ qgsrubberband.h
 qgsvertexmarker.h
 qgsmaptip.h
 qgsscalecombobox.h
+qgsblendmodecombobox.h
 qgssearchquerybuilder.h
 qgsattributeeditor.h
 qgsfieldvalidator.h

src/gui/qgsblendmodecombobox.cpp

@@ -0,0 +1,112 @@
+/***************************************************************************
+                              qgsblendmodecombobox.cpp
+                              ------------------------
+  begin                : March 21, 2013
+  copyright            : (C) 2013 by Nyall Dawson
+  email                : nyall.dawson@gmail.com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgis.h"
+#include "qgslogger.h"
+#include "qgsblendmodecombobox.h"
+
+#include <QAbstractItemView>
+#include <QLocale>
+#include <QSettings>
+#include <QLineEdit>
+
+QgsBlendModeComboBox::QgsBlendModeComboBox( QWidget* parent ) : QComboBox( parent )
+{
+  updateModes();
+}
+
+QgsBlendModeComboBox::~QgsBlendModeComboBox()
+{
+}
+
+/* Returns a QStringList of the translated blend modes
+* "-" is used to indicate the position of a seperator in the list
+* This list is designed to emulate GIMP's layer modes, where
+* blending modes are grouped by their effect (lightening, darkening, etc)
+*/
+QStringList QgsBlendModeComboBox::blendModesList() const
+{
+  return QStringList() << tr( "Normal" )
+         << "-"
+         << tr( "Lighten" )
+         << tr( "Screen" )
+         << tr( "Dodge" )
+         << tr( "Addition" )
+         << "-"
+         << tr( "Darken" )
+         << tr( "Multiply" )
+         << tr( "Burn" )
+         << "-"
+         << tr( "Overlay" )
+         << tr( "Soft light" )
+         << tr( "Hard light" )
+         << "-"
+         << tr( "Difference" )
+         << tr( "Subtract" );
+}
+
+/* Populates the blend mode combo box, and sets up mapping for
+* blend modes to combo box indexes
+*/
+void QgsBlendModeComboBox::updateModes()
+{
+  blockSignals( true );
+  clear();
+
+  QStringList myBlendModesList = blendModesList();
+  QStringList::const_iterator blendModeIt = myBlendModesList.constBegin();
+
+  mBlendModeToListIndex.resize( myBlendModesList.count() );
+  mListIndexToBlendMode.resize( myBlendModesList.count() );
+
+  // Loop through blend modes
+  int index = 0;
+  int blendModeIndex = 0;
+  for ( ; blendModeIt != myBlendModesList.constEnd(); ++blendModeIt )
+  {
+    if ( *blendModeIt == "-" )
+    {
+      // Add seperator
+      insertSeparator( index );
+    }
+    else
+    {
+      // Not a seperator, so store indexes for translation
+      // between blend modes and combo box item index
+      addItem( *blendModeIt );
+      mListIndexToBlendMode[ index ] = blendModeIndex;
+      mBlendModeToListIndex[ blendModeIndex ] = index;
+      blendModeIndex++;
+    }
+    index++;
+  }
+
+  blockSignals( false );
+}
+
+//! Function to read the selected blend mode as int
+int QgsBlendModeComboBox::blendMode()
+{
+  return mListIndexToBlendMode[ currentIndex()];
+}
+
+//! Function to set the selected blend mode from int
+void QgsBlendModeComboBox::setBlendMode( int blendMode )
+{
+  setCurrentIndex( mBlendModeToListIndex[ blendMode ] );
+}
+

src/gui/qgsblendmodecombobox.h

@@ -0,0 +1,51 @@
+/***************************************************************************
+                              qgsblendmodecombobox.h
+                              ------------------------
+  begin                : March 21, 2013
+  copyright            : (C) 2013 by Nyall Dawson
+  email                : nyall.dawson@gmail.com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSBLENDMODECOMBOBOX_H
+#define QGSBLENDMODECOMBOBOX_H
+
+#include <QComboBox>
+
+/** \ingroup gui
+ * A combobox which lets the user select blend modes from a predefined list
+ **/
+class GUI_EXPORT QgsBlendModeComboBox : public QComboBox
+{
+    Q_OBJECT
+  public:
+    QgsBlendModeComboBox( QWidget* parent = 0 );
+    virtual ~QgsBlendModeComboBox();
+
+    //! Function to read the selected blend mode as integer
+    int blendMode();
+    //! Function to set the selected blend mode from integer
+    void setBlendMode( int blendMode );
+  private:
+    //! Returns a list of grouped blend modes (with seperators)
+    QStringList blendModesList() const;
+
+    //! Used to map blend modes across to their corresponding
+    //  index within the combo box
+    std::vector<int> mBlendModeToListIndex;
+    std::vector<int> mListIndexToBlendMode;
+
+  public slots:
+    void updateModes();
+
+};
+
+#endif // QGSBLENDMODECOMBOBOX_H