[FEATURE] Option to convert a raster to grayscale with choice of desa…

…turation mode (lightness, luminosity, average) (fix #5837)
qgis · Mar 26, 2013 · 3d02fbe · 3d02fbe
1 parent 030960e
commit 3d02fbe
Show file tree

Hide file tree

Showing 5 changed files with 136 additions and 18 deletions.
diff --git a/src/app/qgsrasterlayerproperties.cpp b/src/app/qgsrasterlayerproperties.cpp
@@ -87,6 +87,9 @@ QgsRasterLayerProperties::QgsRasterLayerProperties( QgsMapLayer* lyr, QgsMapCanv
   connect( sliderSaturation, SIGNAL( valueChanged( int ) ), spinBoxSaturation, SLOT( setValue( int ) ) );
   connect( spinBoxSaturation, SIGNAL( valueChanged( int ) ), sliderSaturation, SLOT( setValue( int ) ) );
 
+  // enable or disable saturation slider and spin box depending on grayscale combo choice
+  connect( comboGrayscale, SIGNAL( currentIndexChanged( int ) ), this, SLOT( toggleSaturationControls( int ) ) );
+
   // enable or disable Build Pyramids button depending on selection in pyramid list
   connect( lbxPyramidResolutions, SIGNAL( itemSelectionChanged() ), this, SLOT( toggleBuildPyramidsButton() ) );
 
@@ -255,6 +258,10 @@ QgsRasterLayerProperties::QgsRasterLayerProperties( QgsMapLayer* lyr, QgsMapCanv
   if ( hueSaturationFilter )
   {
     sliderSaturation->setValue( hueSaturationFilter->saturation() );
+    comboGrayscale->setCurrentIndex(( int ) hueSaturationFilter->grayscaleMode() );
+
+    // Set initial state of saturation controls based on grayscale mode choice
+    toggleSaturationControls( hueSaturationFilter->grayscaleMode() == QgsHueSaturationFilter::GrayscaleOff );
   }
 
   //blend mode
@@ -820,6 +827,7 @@ void QgsRasterLayerProperties::apply()
   if ( hueSaturationFilter )
   {
     hueSaturationFilter->setSaturation( sliderSaturation->value() );
+    hueSaturationFilter->setGrayscaleMode(( QgsHueSaturationFilter::GrayscaleMode ) comboGrayscale->currentIndex() );
   }
 
 
@@ -1456,6 +1464,23 @@ void QgsRasterLayerProperties::sliderTransparency_valueChanged( int theValue )
   lblTransparencyPercent->setText( QString::number( myInt ) + "%" );
 }//sliderTransparency_valueChanged
 
+void QgsRasterLayerProperties::toggleSaturationControls( int theValue )
+{
+  // Enable or disable saturation controls based on choice of grayscale mode
+  if ( theValue == 0 )
+  {
+    // Grayscale set to off, enable controls
+    sliderSaturation->setEnabled( true );
+    spinBoxSaturation->setEnabled( true );
+  }
+  else
+  {
+    // A grayscale mode is selected, disable saturation controls
+    sliderSaturation->setEnabled( false );
+    spinBoxSaturation->setEnabled( false );
+  }
+}
+
 QLinearGradient QgsRasterLayerProperties::redGradient()
 {
   //define a gradient

diff --git a/src/app/qgsrasterlayerproperties.h b/src/app/qgsrasterlayerproperties.h
@@ -103,6 +103,9 @@ class QgsRasterLayerProperties : public QDialog, private Ui::QgsRasterLayerPrope
     /**Enable or disable Build pyramids button depending on selection in pyramids list*/
     void toggleBuildPyramidsButton();
 
+    /**Enable or disable saturation controls depending on choice of grayscale mode */
+    void toggleSaturationControls( int theValue );
+
     /** Update items in pipe list */
     void pipeItemClicked( QTreeWidgetItem * item, int column );
 

diff --git a/src/core/raster/qgshuesaturationfilter.cpp b/src/core/raster/qgshuesaturationfilter.cpp
@@ -24,7 +24,8 @@
 
 QgsHueSaturationFilter::QgsHueSaturationFilter( QgsRasterInterface* input )
     : QgsRasterInterface( input ),
-    mSaturation( 0 )
+    mSaturation( 0 ),
+    mGrayscaleMode( QgsHueSaturationFilter::GrayscaleOff )
 {
 }
 
@@ -128,9 +129,9 @@ QgsRasterBlock * QgsHueSaturationFilter::block( int bandNo, QgsRectangle  const
     return outputBlock;
   }
 
-  if ( mSaturation == 0 )
+  if ( mSaturation == 0 && mGrayscaleMode == GrayscaleOff )
   {
-    QgsDebugMsg( "No saturation change." );
+    QgsDebugMsg( "No hue/saturation change." );
     delete outputBlock;
     return inputBlock;
   }
@@ -144,7 +145,8 @@ QgsRasterBlock * QgsHueSaturationFilter::block( int bandNo, QgsRectangle  const
   // adjust image
   QRgb myNoDataColor = qRgba( 0, 0, 0, 0 );
   QColor myColor;
-  int h, s, v;
+  int h, s, l;
+  int r, g, b;
 
   // Scale saturation value to [0-2], where 0 = desaturated
   double saturationScale = (( double ) mSaturation / 100 ) + 1;
@@ -157,24 +159,56 @@ QgsRasterBlock * QgsHueSaturationFilter::block( int bandNo, QgsRectangle  const
       continue;
     }
 
-    // Get current color in hsv
+    // Get hsv and rgb for color
     myColor = QColor( inputBlock->color( i ) );
-    myColor.getHsv( &h, &s, &v );
+    myColor.getHsl( &h, &s, &l );
+    myColor.getRgb( &r, &g, &b );
 
-    if ( saturationScale < 1 )
+    switch ( mGrayscaleMode )
     {
-      // Lowering the saturation. Use a simple linear relationship
-      s = qMin(( int )( s * saturationScale ), 255 );
-    }
-    else
-    {
-      // Raising the saturation. Use a saturation curve to prevent
-      // clipping at maximum saturation with ugly results.
-      s = qMin(( int )( 255. * ( 1 - pow( 1 - (( double )s / 255. )  , saturationScale * 2 ) ) ), 255 );
+      case GrayscaleLightness:
+      {
+        // Lightness mode, set saturation to zero
+        s = 0;
+        myColor = QColor::fromHsl( h, s, l );
+        break;
+      }
+      case GrayscaleLuminosity:
+      {
+        // Grayscale by weighted rgb components
+        int luminosity = 0.21 * r + 0.72 * g + 0.07 * b;
+        r = g = b = luminosity;
+        myColor = QColor::fromRgb( r, g, b );
+        break;
+      }
+      case GrayscaleAverage:
+      {
+        // Grayscale by average of rgb components
+        int average = ( r + g + b ) / 3;
+        r = g = b = average;
+        myColor = QColor::fromRgb( r, g, b );
+        break;
+      }
+      case GrayscaleOff:
+      {
+        // Not being made grayscale, do saturation change
+        if ( saturationScale < 1 )
+        {
+          // Lowering the saturation. Use a simple linear relationship
+          s = qMin(( int )( s * saturationScale ), 255 );
+        }
+        else
+        {
+          // Raising the saturation. Use a saturation curve to prevent
+          // clipping at maximum saturation with ugly results.
+          s = qMin(( int )( 255. * ( 1 - pow( 1 - (( double )s / 255. )  , saturationScale * 2 ) ) ), 255 );
+        }
+        myColor = QColor::fromHsl( h, s, l );
+        break;
+      }
     }
 
     // Convert back to rgb
-    myColor = QColor::fromHsv( h, s, v );
     outputBlock->setColor( i, myColor.rgb() );
   }
 
@@ -192,6 +226,7 @@ void QgsHueSaturationFilter::writeXML( QDomDocument& doc, QDomElement& parentEle
   QDomElement filterElem = doc.createElement( "huesaturation" );
 
   filterElem.setAttribute( "saturation", QString::number( mSaturation ) );
+  filterElem.setAttribute( "grayscaleMode", QString::number( mGrayscaleMode ) );
   parentElem.appendChild( filterElem );
 }
 
@@ -203,4 +238,5 @@ void QgsHueSaturationFilter::readXML( const QDomElement& filterElem )
   }
 
   mSaturation = filterElem.attribute( "saturation", "0" ).toInt();
+  mGrayscaleMode = ( QgsHueSaturationFilter::GrayscaleMode )filterElem.attribute( "grayscaleMode", "0" ).toInt();
 }
diff --git a/src/core/raster/qgshuesaturationfilter.h b/src/core/raster/qgshuesaturationfilter.h
@@ -29,6 +29,16 @@ class QDomElement;
 class CORE_EXPORT QgsHueSaturationFilter : public QgsRasterInterface
 {
   public:
+
+    // Available modes for converting a raster to grayscale
+    enum GrayscaleMode
+    {
+      GrayscaleOff,
+      GrayscaleLightness,
+      GrayscaleLuminosity,
+      GrayscaleAverage
+    };
+
     QgsHueSaturationFilter( QgsRasterInterface *input = 0 );
     ~QgsHueSaturationFilter();
 
@@ -45,6 +55,9 @@ class CORE_EXPORT QgsHueSaturationFilter : public QgsRasterInterface
     void setSaturation( int saturation ) { mSaturation = qBound( -100, saturation, 100 ); }
     int saturation() const { return mSaturation; }
 
+    void setGrayscaleMode( QgsHueSaturationFilter::GrayscaleMode grayscaleMode ) { mGrayscaleMode = grayscaleMode; }
+    QgsHueSaturationFilter::GrayscaleMode grayscaleMode() const { return mGrayscaleMode; }
+
     void writeXML( QDomDocument& doc, QDomElement& parentElem );
 
     /**Sets base class members from xml. Usually called from create() methods of subclasses*/
@@ -54,6 +67,9 @@ class CORE_EXPORT QgsHueSaturationFilter : public QgsRasterInterface
     /**Current saturation value. Range: -100 (desaturated) ... 0 (no change) ... 100 (increased)*/
     int mSaturation;
 
+    /**Current grayscale mode*/
+    QgsHueSaturationFilter::GrayscaleMode mGrayscaleMode;
+
 };
 
 #endif // QGSHUESATURATIONFILTER_H
diff --git a/src/ui/qgsrasterlayerpropertiesbase.ui b/src/ui/qgsrasterlayerpropertiesbase.ui
@@ -263,7 +263,7 @@
           <bool>true</bool>
          </property>
          <layout class="QGridLayout" name="_7">
-          <item row="0" column="0">
+          <item row="0" column="1">
            <widget class="QSlider" name="sliderSaturation">
             <property name="sizePolicy">
              <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
@@ -288,7 +288,7 @@
             </property>
            </widget>
           </item>
-          <item row="0" column="1">
+          <item row="0" column="2">
            <widget class="QSpinBox" name="spinBoxSaturation">
             <property name="minimum">
              <number>-100</number>
@@ -304,6 +304,44 @@
             </property>
            </widget>
           </item>
+          <item row="0" column="0">
+           <widget class="QLabel" name="labelSaturation">
+            <property name="text">
+             <string>Saturation</string>
+            </property>
+           </widget>
+          </item>
+          <item row="0" column="4">
+           <widget class="QLabel" name="labelGrayscale">
+            <property name="text">
+             <string>Grayscale</string>
+            </property>
+           </widget>
+          </item>
+          <item row="0" column="5">
+           <widget class="QComboBox" name="comboGrayscale">
+            <item>
+             <property name="text">
+              <string>Off</string>
+             </property>
+            </item>
+            <item>
+             <property name="text">
+              <string>By lightness</string>
+             </property>
+            </item>
+            <item>
+             <property name="text">
+              <string>By luminosity</string>
+             </property>
+            </item>
+            <item>
+             <property name="text">
+              <string>By average</string>
+             </property>
+            </item>
+           </widget>
+          </item>
          </layout>
         </widget>
        </item>