[api] Add virtual QgsRasterRenderer::setInputBand method

Attempts to set the input band for the renderer.
Returns TRUE if the band was successfully set, or FALSE if the
band could not be set.

This was implemented in various raster renderer subclasses,
but it was necessary to down cast and then call the individual
methods (which don't have consistent names!).

Instead, add a top level virtual method so that it's easy to
change the input band for the renderers.

python/PyQt6/core/auto_generated/raster/qgshillshaderenderer.sip.in

@@ -71,6 +71,8 @@ Sets the band used by the renderer.
 
 .. seealso:: :py:func:`band`
 %End
+    virtual bool setInputBand( int band );
+
 
     double azimuth() const;
 %Docstring

python/PyQt6/core/auto_generated/raster/qgspalettedrasterrenderer.sip.in

@@ -127,6 +127,9 @@ Set category label
 Returns the raster band used for rendering the raster.
 %End
 
+    virtual bool setInputBand( int band );
+
+
     virtual void writeXml( QDomDocument &doc, QDomElement &parentElem ) const;
 
     virtual QList< QPair< QString, QColor > > legendSymbologyItems() const;

python/PyQt6/core/auto_generated/raster/qgsrastercontourrenderer.sip.in

@@ -56,10 +56,8 @@ Creates an instance of the renderer based on definition from XML (used by render
 %Docstring
 Returns the number of the input raster band
 %End
-    void setInputBand( int band );
-%Docstring
-Sets the number of the input raster band
-%End
+    virtual bool setInputBand( int band );
+
 
     double contourInterval() const;
 %Docstring

python/PyQt6/core/auto_generated/raster/qgsrasterrenderer.sip.in

@@ -67,6 +67,19 @@ The default implementation returns ``False``.
     virtual bool setInput( QgsRasterInterface *input );
 
 
+    virtual bool setInputBand( int band );
+%Docstring
+Attempts to set the input ``band`` for the renderer.
+
+Returns ``True`` if the band was successfully set, or ``False`` if the band could not be set.
+
+.. note::
+
+   Not all renderers support setting the input band.
+
+.. versionadded:: 3.38
+%End
+
      virtual QgsRasterBlock *block( int bandNo,
                            const QgsRectangle &extent,
                            int width,

python/PyQt6/core/auto_generated/raster/qgssinglebandcolordatarenderer.sip.in

@@ -35,6 +35,8 @@ QgsSingleBandColorDataRenderer cannot be copied. Use :py:func:`~QgsSingleBandCol
 
     virtual bool setInput( QgsRasterInterface *input );
 
+    virtual bool setInputBand( int band );
+
 
     virtual QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback *feedback = 0 ) /Factory/;
 

python/PyQt6/core/auto_generated/raster/qgssinglebandgrayrenderer.sip.in

@@ -45,6 +45,9 @@ QgsSingleBandGrayRenderer cannot be copied. Use :py:func:`~QgsSingleBandGrayRend
 
     int grayBand() const;
     void setGrayBand( int band );
+    virtual bool setInputBand( int band );
+
+
     const QgsContrastEnhancement *contrastEnhancement() const;
     void setContrastEnhancement( QgsContrastEnhancement *ce /Transfer/ );
 %Docstring

python/PyQt6/core/auto_generated/raster/qgssinglebandpseudocolorrenderer.sip.in

@@ -101,6 +101,8 @@ Sets the band used by the renderer.
 
 .. seealso:: :py:func:`band`
 %End
+    virtual bool setInputBand( int band );
+
 
     double classificationMin() const;
     double classificationMax() const;

python/core/auto_generated/raster/qgshillshaderenderer.sip.in

@@ -71,6 +71,8 @@ Sets the band used by the renderer.
 
 .. seealso:: :py:func:`band`
 %End
+    virtual bool setInputBand( int band );
+
 
     double azimuth() const;
 %Docstring

python/core/auto_generated/raster/qgspalettedrasterrenderer.sip.in

@@ -127,6 +127,9 @@ Set category label
 Returns the raster band used for rendering the raster.
 %End
 
+    virtual bool setInputBand( int band );
+
+
     virtual void writeXml( QDomDocument &doc, QDomElement &parentElem ) const;
 
     virtual QList< QPair< QString, QColor > > legendSymbologyItems() const;

python/core/auto_generated/raster/qgsrastercontourrenderer.sip.in

@@ -56,10 +56,8 @@ Creates an instance of the renderer based on definition from XML (used by render
 %Docstring
 Returns the number of the input raster band
 %End
-    void setInputBand( int band );
-%Docstring
-Sets the number of the input raster band
-%End
+    virtual bool setInputBand( int band );
+
 
     double contourInterval() const;
 %Docstring

python/core/auto_generated/raster/qgsrasterrenderer.sip.in

@@ -67,6 +67,19 @@ The default implementation returns ``False``.
     virtual bool setInput( QgsRasterInterface *input );
 
 
+    virtual bool setInputBand( int band );
+%Docstring
+Attempts to set the input ``band`` for the renderer.
+
+Returns ``True`` if the band was successfully set, or ``False`` if the band could not be set.
+
+.. note::
+
+   Not all renderers support setting the input band.
+
+.. versionadded:: 3.38
+%End
+
      virtual QgsRasterBlock *block( int bandNo,
                            const QgsRectangle &extent,
                            int width,

python/core/auto_generated/raster/qgssinglebandcolordatarenderer.sip.in

@@ -35,6 +35,8 @@ QgsSingleBandColorDataRenderer cannot be copied. Use :py:func:`~QgsSingleBandCol
 
     virtual bool setInput( QgsRasterInterface *input );
 
+    virtual bool setInputBand( int band );
+
 
     virtual QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback *feedback = 0 ) /Factory/;
 

python/core/auto_generated/raster/qgssinglebandgrayrenderer.sip.in

@@ -45,6 +45,9 @@ QgsSingleBandGrayRenderer cannot be copied. Use :py:func:`~QgsSingleBandGrayRend
 
     int grayBand() const;
     void setGrayBand( int band );
+    virtual bool setInputBand( int band );
+
+
     const QgsContrastEnhancement *contrastEnhancement() const;
     void setContrastEnhancement( QgsContrastEnhancement *ce /Transfer/ );
 %Docstring

python/core/auto_generated/raster/qgssinglebandpseudocolorrenderer.sip.in

@@ -101,6 +101,8 @@ Sets the band used by the renderer.
 
 .. seealso:: :py:func:`band`
 %End
+    virtual bool setInputBand( int band );
+
 
     double classificationMin() const;
     double classificationMax() const;

src/core/raster/qgshillshaderenderer.cpp

@@ -571,11 +571,17 @@ QList<int> QgsHillshadeRenderer::usesBands() const
 
 void QgsHillshadeRenderer::setBand( int bandNo )
 {
-  if ( bandNo > mInput->bandCount() || bandNo <= 0 )
+  setInputBand( bandNo );
+}
+
+bool QgsHillshadeRenderer::setInputBand( int band )
+{
+  if ( band > mInput->bandCount() || band <= 0 )
   {
-    return;
+    return false;
   }
-  mBand = bandNo;
+  mBand = band;
+  return true;
 }
 
 void QgsHillshadeRenderer::toSld( QDomDocument &doc, QDomElement &element, const QVariantMap &props ) const

src/core/raster/qgshillshaderenderer.h

@@ -74,6 +74,7 @@ class CORE_EXPORT QgsHillshadeRenderer : public QgsRasterRenderer
      * \see band
      */
     void setBand( int bandNo );
+    bool setInputBand( int band ) override;
 
     /**
      * Returns the direction of the light over the raster between 0-360.

src/core/raster/qgspalettedrasterrenderer.cpp

@@ -175,6 +175,12 @@ void QgsPalettedRasterRenderer::setLabel( double idx, const QString &label )
   }
 }
 
+bool QgsPalettedRasterRenderer::setInputBand( int band )
+{
+  mBand = band;
+  return true;
+}
+
 QgsRasterBlock *QgsPalettedRasterRenderer::block( int, QgsRectangle  const &extent, int width, int height, QgsRasterBlockFeedback *feedback )
 {
   std::unique_ptr< QgsRasterBlock > outputBlock( new QgsRasterBlock() );

src/core/raster/qgspalettedrasterrenderer.h

@@ -146,6 +146,8 @@ class CORE_EXPORT QgsPalettedRasterRenderer: public QgsRasterRenderer
      */
     int band() const { return mBand; }
 
+    bool setInputBand( int band ) override;
+
     void writeXml( QDomDocument &doc, QDomElement &parentElem ) const override;
     QList< QPair< QString, QColor > > legendSymbologyItems() const override;
     QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) SIP_FACTORY override;

src/core/raster/qgsrastercontourrenderer.cpp

@@ -232,6 +232,12 @@ QList<QgsLayerTreeModelLegendNode *> QgsRasterContourRenderer::createLegendNodes
   return nodes;
 }
 
+bool QgsRasterContourRenderer::setInputBand( int band )
+{
+  mInputBand = band;
+  return true;
+}
+
 void QgsRasterContourRenderer::setContourSymbol( QgsLineSymbol *symbol )
 {
   mContourSymbol.reset( symbol );

src/core/raster/qgsrastercontourrenderer.h

@@ -55,8 +55,7 @@ class CORE_EXPORT QgsRasterContourRenderer : public QgsRasterRenderer
 
     //! Returns the number of the input raster band
     int inputBand() const { return mInputBand; }
-    //! Sets the number of the input raster band
-    void setInputBand( int band ) { mInputBand = band; }
+    bool setInputBand( int band ) override;
 
     //! Returns the interval of contour lines generation
     double contourInterval() const { return mContourInterval; }

src/core/raster/qgsrasterrenderer.cpp

@@ -97,6 +97,11 @@ bool QgsRasterRenderer::setInput( QgsRasterInterface *input )
   return true;
 }
 
+bool QgsRasterRenderer::setInputBand( int )
+{
+  return false;
+}
+
 bool QgsRasterRenderer::usesTransparency() const
 {
   if ( !mInput )

src/core/raster/qgsrasterrenderer.h

@@ -85,6 +85,17 @@ class CORE_EXPORT QgsRasterRenderer : public QgsRasterInterface
 
     bool setInput( QgsRasterInterface *input ) override;
 
+    /**
+     * Attempts to set the input \a band for the renderer.
+     *
+     * Returns TRUE if the band was successfully set, or FALSE if the band could not be set.
+     *
+     * \note Not all renderers support setting the input band.
+     *
+     * \since QGIS 3.38
+     */
+    virtual bool setInputBand( int band );
+
     QgsRasterBlock *block( int bandNo,
                            const QgsRectangle &extent,
                            int width,

src/core/raster/qgssinglebandcolordatarenderer.cpp

@@ -23,8 +23,9 @@
 #include <QImage>
 #include <memory>
 
-QgsSingleBandColorDataRenderer::QgsSingleBandColorDataRenderer( QgsRasterInterface *input, int band ):
-  QgsRasterRenderer( input, QStringLiteral( "singlebandcolordata" ) ), mBand( band )
+QgsSingleBandColorDataRenderer::QgsSingleBandColorDataRenderer( QgsRasterInterface *input, int band )
+  : QgsRasterRenderer( input, QStringLiteral( "singlebandcolordata" ) )
+  , mBand( band )
 {
 
 }
@@ -139,3 +140,9 @@ bool QgsSingleBandColorDataRenderer::setInput( QgsRasterInterface *input )
   }
   return false;
 }
+
+bool QgsSingleBandColorDataRenderer::setInputBand( int band )
+{
+  mBand = band;
+  return true;
+}

src/core/raster/qgssinglebandcolordatarenderer.h

@@ -44,6 +44,7 @@ class CORE_EXPORT QgsSingleBandColorDataRenderer: public QgsRasterRenderer
     static QgsRasterRenderer *create( const QDomElement &elem, QgsRasterInterface *input ) SIP_FACTORY;
 
     bool setInput( QgsRasterInterface *input ) override;
+    bool setInputBand( int band ) override;
 
     QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback *feedback = nullptr ) override SIP_FACTORY;
 

src/core/raster/qgssinglebandgrayrenderer.cpp

@@ -193,6 +193,17 @@ QgsRasterBlock *QgsSingleBandGrayRenderer::block( int bandNo, const QgsRectangle
   return outputBlock.release();
 }
 
+void QgsSingleBandGrayRenderer::setGrayBand( int band )
+{
+  setInputBand( band );
+}
+
+bool QgsSingleBandGrayRenderer::setInputBand( int band )
+{
+  mGrayBand = band;
+  return true;
+}
+
 void QgsSingleBandGrayRenderer::writeXml( QDomDocument &doc, QDomElement &parentElem ) const
 {
   if ( parentElem.isNull() )

src/core/raster/qgssinglebandgrayrenderer.h

@@ -56,7 +56,9 @@ class CORE_EXPORT QgsSingleBandGrayRenderer: public QgsRasterRenderer
     QgsRasterBlock *block( int bandNo, const QgsRectangle &extent, int width, int height, QgsRasterBlockFeedback *feedback = nullptr ) override SIP_FACTORY;
 
     int grayBand() const { return mGrayBand; }
-    void setGrayBand( int band ) { mGrayBand = band; }
+    void setGrayBand( int band );
+    bool setInputBand( int band ) override;
+
     const QgsContrastEnhancement *contrastEnhancement() const { return mContrastEnhancement.get(); }
     //! Takes ownership
     void setContrastEnhancement( QgsContrastEnhancement *ce SIP_TRANSFER );

src/core/raster/qgssinglebandpseudocolorrenderer.cpp

@@ -37,17 +37,23 @@ QgsSingleBandPseudoColorRenderer::QgsSingleBandPseudoColorRenderer( QgsRasterInt
 }
 
 void QgsSingleBandPseudoColorRenderer::setBand( int bandNo )
+{
+  setInputBand( bandNo );
+}
+
+bool QgsSingleBandPseudoColorRenderer::setInputBand( int band )
 {
   if ( !mInput )
   {
-    mBand = bandNo;
-    return;
+    mBand = band;
+    return true;
   }
-
-  if ( bandNo <= mInput->bandCount() || bandNo > 0 )
+  else if ( band <= mInput->bandCount() || band > 0 )
   {
-    mBand = bandNo;
+    mBand = band;
+    return true;
   }
+  return false;
 }
 
 void QgsSingleBandPseudoColorRenderer::setClassificationMin( double min )
@@ -481,3 +487,4 @@ bool QgsSingleBandPseudoColorRenderer::canCreateRasterAttributeTable() const
 {
   return true;
 }
+

src/core/raster/qgssinglebandpseudocolorrenderer.h

@@ -95,6 +95,7 @@ class CORE_EXPORT QgsSingleBandPseudoColorRenderer: public QgsRasterRenderer
      * \see band
      */
     void setBand( int bandNo );
+    bool setInputBand( int band ) override;
 
     double classificationMin() const { return mClassificationMin; }
     double classificationMax() const { return mClassificationMax; }