Add an invert checkbox for heatmap renderer

python/core/symbology-ng/qgsheatmaprenderer.sip

@@ -37,6 +37,19 @@ class QgsHeatmapRenderer : QgsFeatureRendererV2
      * @see colorRamp
     */
     void setColorRamp( QgsVectorColorRampV2* ramp /Transfer/ );
+    
+    /**Returns whether the ramp is inverted
+     * @returns true if color ramp is inverted
+     * @see setInvertRamp
+     * @see colorRamp
+    */
+    double invertRamp() const;
+    /**Sets whether the ramp is inverted
+     * @param invert set to true to invert color ramp
+     * @see invertRamp
+     * @see setColorRamp
+    */
+    void setInvertRamp( const bool invert );
 
     /**Returns the radius for the heatmap
      * @returns heatmap radius

src/core/symbology-ng/qgsheatmaprenderer.cpp

@@ -34,6 +34,7 @@ QgsHeatmapRenderer::QgsHeatmapRenderer( )
     , mRadius( 10 )
     , mRadiusUnit( QgsSymbolV2::MM )
     , mGradientRamp( 0 )
+    , mInvertRamp( false )
     , mExplicitMax( 0.0 )
     , mRenderQuality( 1 )
 {
@@ -208,7 +209,7 @@ void QgsHeatmapRenderer::renderImage( QgsRenderContext& context )
       pixVal = mValues.at( idx ) > 0 ? qMin(( mValues.at( idx ) / scaleMax ), 1.0 ) : 0;
 
       //convert value to color from ramp
-      pixColor = mGradientRamp->color( pixVal );
+      pixColor = mGradientRamp->color( mInvertRamp ? 1 - pixVal : pixVal );
 
       scanLine[widthIndex] = pixColor.rgba();
       idx++;
@@ -239,6 +240,7 @@ QgsFeatureRendererV2* QgsHeatmapRenderer::clone() const
   {
     newRenderer->setColorRamp( mGradientRamp->clone() );
   }
+  newRenderer->setInvertRamp( mInvertRamp );
   newRenderer->setRadius( mRadius );
   newRenderer->setRadiusUnit( mRadiusUnit );
   newRenderer->setRadiusMapUnitScale( mRadiusMapUnitScale );
@@ -286,6 +288,7 @@ QgsFeatureRendererV2* QgsHeatmapRenderer::create( QDomElement& element )
   {
     r->setColorRamp( QgsSymbolLayerV2Utils::loadColorRamp( sourceColorRampElem ) );
   }
+  r->setInvertRamp( element.attribute( "invert_ramp", "0" ).toInt() );
   return r;
 }
 
@@ -303,6 +306,7 @@ QDomElement QgsHeatmapRenderer::save( QDomDocument& doc )
     QDomElement colorRampElem = QgsSymbolLayerV2Utils::saveColorRamp( "[source]", mGradientRamp, doc );
     rendererElem.appendChild( colorRampElem );
   }
+  rendererElem.setAttribute( "invert_ramp", QString::number( mInvertRamp ) );
 
   return rendererElem;
 }

src/core/symbology-ng/qgsheatmaprenderer.h

@@ -67,6 +67,19 @@ class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRendererV2
     */
     void setColorRamp( QgsVectorColorRampV2* ramp );
 
+    /**Returns whether the ramp is inverted
+     * @returns true if color ramp is inverted
+     * @see setInvertRamp
+     * @see colorRamp
+    */
+    double invertRamp() const { return mInvertRamp; }
+    /**Sets whether the ramp is inverted
+     * @param invert set to true to invert color ramp
+     * @see invertRamp
+     * @see setColorRamp
+    */
+    void setInvertRamp( const bool invert ) { mInvertRamp = invert; }
+
     /**Returns the radius for the heatmap
      * @returns heatmap radius
      * @see setRadius
@@ -155,6 +168,7 @@ class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRendererV2
     QgsMapUnitScale mRadiusMapUnitScale;
 
     QgsVectorColorRampV2* mGradientRamp;
+    bool mInvertRamp;
 
     double mExplicitMax;
     int mRenderQuality;

src/gui/symbology-ng/qgsheatmaprendererwidget.cpp

@@ -97,6 +97,9 @@ QgsHeatmapRendererWidget::QgsHeatmapRendererWidget( QgsVectorLayer* layer, QgsSt
   mQualitySlider->blockSignals( true );
   mQualitySlider->setValue( mRenderer->renderQuality() );
   mQualitySlider->blockSignals( false );
+  mInvertCheckBox->blockSignals( true );
+  mInvertCheckBox->setChecked( mRenderer->invertRamp() );
+  mInvertCheckBox->blockSignals( false );
 }
 
 QgsFeatureRendererV2* QgsHeatmapRendererWidget::renderer()
@@ -193,3 +196,13 @@ void QgsHeatmapRendererWidget::on_mQualitySlider_valueChanged( int v )
 
   mRenderer->setRenderQuality( v );
 }
+
+void QgsHeatmapRendererWidget::on_mInvertCheckBox_toggled( bool v )
+{
+  if ( !mRenderer )
+  {
+    return;
+  }
+
+  mRenderer->setInvertRamp( v );
+}

src/gui/symbology-ng/qgsheatmaprendererwidget.h

@@ -54,6 +54,7 @@ class GUI_EXPORT QgsHeatmapRendererWidget : public QgsRendererV2Widget, private
     void on_mRadiusSpinBox_valueChanged( double d );
     void on_mMaxSpinBox_valueChanged( double d );
     void on_mQualitySlider_valueChanged( int v );
+    void on_mInvertCheckBox_toggled( bool v );
 
 };
 

src/ui/symbollayer/qgsheatmaprendererwidgetbase.ui

@@ -15,7 +15,7 @@
   </property>
   <layout class="QGridLayout" name="gridLayout" columnstretch="0,1">
    <item row="0" column="0" colspan="2">
-    <layout class="QHBoxLayout" name="horizontalLayout" stretch="1,0">
+    <layout class="QHBoxLayout" name="horizontalLayout" stretch="1,0,0">
      <item>
       <widget class="QgsColorRampComboBox" name="mRampComboBox"/>
      </item>
@@ -32,16 +32,23 @@
        </property>
       </widget>
      </item>
+     <item>
+      <widget class="QCheckBox" name="mInvertCheckBox">
+       <property name="text">
+        <string>Invert</string>
+       </property>
+      </widget>
+     </item>
     </layout>
    </item>
-   <item row="1" column="0">
+   <item row="2" column="0">
     <widget class="QLabel" name="label_2">
      <property name="text">
       <string>Radius</string>
      </property>
     </widget>
    </item>
-   <item row="1" column="1">
+   <item row="2" column="1">
     <layout class="QHBoxLayout" name="horizontalLayout_2">
      <item>
       <widget class="QgsDoubleSpinBox" name="mRadiusSpinBox">
@@ -67,14 +74,14 @@
      </item>
     </layout>
    </item>
-   <item row="2" column="0">
+   <item row="3" column="0">
     <widget class="QLabel" name="label">
      <property name="text">
       <string>Maximum value</string>
      </property>
     </widget>
    </item>
-   <item row="2" column="1">
+   <item row="3" column="1">
     <widget class="QgsDoubleSpinBox" name="mMaxSpinBox">
      <property name="sizePolicy">
       <sizepolicy hsizetype="Minimum" vsizetype="Fixed">
@@ -96,14 +103,14 @@
      </property>
     </widget>
    </item>
-   <item row="3" column="0">
+   <item row="4" column="0">
     <widget class="QLabel" name="label_3">
      <property name="text">
       <string>Rendering quality</string>
      </property>
     </widget>
    </item>
-   <item row="3" column="1">
+   <item row="4" column="1">
     <layout class="QHBoxLayout" name="horizontalLayout_3">
      <item>
       <widget class="QLabel" name="label_4">
@@ -152,7 +159,7 @@
      </item>
     </layout>
    </item>
-   <item row="4" column="1">
+   <item row="5" column="1">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -188,6 +195,7 @@
  <tabstops>
   <tabstop>mRampComboBox</tabstop>
   <tabstop>mButtonEditRamp</tabstop>
+  <tabstop>mInvertCheckBox</tabstop>
   <tabstop>mRadiusSpinBox</tabstop>
   <tabstop>mMaxSpinBox</tabstop>
   <tabstop>mQualitySlider</tabstop>