[api] Attach QgsPropertyCollection to QgsRasterPipe to allow

for data-defined raster pipeline properties

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

@@ -11,6 +11,7 @@
 
 
 
+
 class QgsRasterPipe
 {
 %Docstring(signature="appended")
@@ -22,6 +23,11 @@ Contains a pipeline of raster interfaces for sequential raster processing.
 %End
   public:
 
+    enum Property
+    {
+      RendererOpacity,
+    };
+
     QgsRasterPipe();
 %Docstring
 Constructor for an empty QgsRasterPipe.
@@ -182,6 +188,44 @@ Returns which stage of the pipe should apply resampling
 .. seealso:: :py:func:`setResamplingStage`
 
 .. versionadded:: 3.16
+%End
+
+    QgsPropertyCollection &dataDefinedProperties();
+%Docstring
+Returns a reference to the pipe's property collection, used for data defined overrides.
+
+.. seealso:: :py:func:`setDataDefinedProperties`
+
+.. versionadded:: 3.22
+%End
+
+
+    void setDataDefinedProperties( const QgsPropertyCollection &collection );
+%Docstring
+Sets the pipe's property ``collection``, used for data defined overrides.
+
+Any existing properties will be discarded.
+
+.. seealso:: :py:func:`dataDefinedProperties`
+
+.. seealso:: Property
+
+.. versionadded:: 3.22
+%End
+
+    void evaluateDataDefinedProperties( QgsExpressionContext &context );
+%Docstring
+Evalutes any data defined properties set on the pipe, applying their results
+to the corresponding interfaces in place.
+
+.. versionadded:: 3.22
+%End
+
+    static QgsPropertiesDefinition propertyDefinitions();
+%Docstring
+Returns the definitions for data defined properties available for use in raster pipes.
+
+.. versionadded:: 3.22
 %End
 
   private:

src/core/raster/qgsrasterlayer.cpp

@@ -168,6 +168,7 @@ QgsRasterLayer *QgsRasterLayer::clone() const
     if ( mPipe->at( i ) )
       layer->pipe()->set( mPipe->at( i )->clone() );
   }
+  layer->pipe()->setDataDefinedProperties( mPipe->dataDefinedProperties() );
 
   return layer;
 }
@@ -1979,6 +1980,10 @@ bool QgsRasterLayer::readSymbology( const QDomNode &layer_node, QString &errorMe
     setBlendMode( QgsPainting::getCompositionMode( static_cast< QgsPainting::BlendMode >( e.text().toInt() ) ) );
   }
 
+  QDomElement elemDataDefinedProperties = layer_node.firstChildElement( QStringLiteral( "pipe-data-defined-properties" ) );
+  if ( !elemDataDefinedProperties.isNull() )
+    mPipe->dataDefinedProperties().readXml( elemDataDefinedProperties, QgsRasterPipe::propertyDefinitions() );
+
   readCustomProperties( layer_node );
 
   return true;
@@ -2181,6 +2186,10 @@ bool QgsRasterLayer::writeSymbology( QDomNode &layer_node, QDomDocument &documen
     interface->writeXml( document, pipeElement );
   }
 
+  QDomElement elemDataDefinedProperties = document.createElement( QStringLiteral( "pipe-data-defined-properties" ) );
+  mPipe->dataDefinedProperties().writeXml( elemDataDefinedProperties, QgsRasterPipe::propertyDefinitions() );
+  layer_node.appendChild( elemDataDefinedProperties );
+
   QDomElement resamplingStageElement = document.createElement( QStringLiteral( "resamplingStage" ) );
   QDomText resamplingStageText = document.createTextNode( resamplingStage() == Qgis::RasterResamplingStage::Provider ? QStringLiteral( "provider" ) : QStringLiteral( "resamplingFilter" ) );
   resamplingStageElement.appendChild( resamplingStageText );

src/core/raster/qgsrasterlayerrenderer.cpp

@@ -254,6 +254,8 @@ QgsRasterLayerRenderer::QgsRasterLayerRenderer( QgsRasterLayer *layer, QgsRender
     layer->refreshRendererIfNeeded( rasterRenderer, rendererContext.extent() );
   }
 
+  mPipe->evaluateDataDefinedProperties( rendererContext.expressionContext() );
+
   const QgsRasterLayerTemporalProperties *temporalProperties = qobject_cast< const QgsRasterLayerTemporalProperties * >( layer->temporalProperties() );
   if ( temporalProperties->isActive() && renderContext()->isTemporal() )
   {

src/core/raster/qgsrasterpipe.cpp

@@ -29,6 +29,8 @@
 #include "qgsrasterprojector.h"
 #include "qgsrasternuller.h"
 
+#include <mutex>
+
 QgsRasterPipe::QgsRasterPipe( const QgsRasterPipe &pipe )
 {
   for ( int i = 0; i < pipe.size(); i++ )
@@ -49,6 +51,7 @@ QgsRasterPipe::QgsRasterPipe( const QgsRasterPipe &pipe )
     }
   }
   setResamplingStage( pipe.resamplingStage() );
+  mDataDefinedProperties = pipe.mDataDefinedProperties;
 }
 
 QgsRasterPipe::~QgsRasterPipe()
@@ -381,3 +384,46 @@ void QgsRasterPipe::setResamplingStage( Qgis::RasterResamplingStage stage )
     l_provider->enableProviderResampling( stage == Qgis::RasterResamplingStage::Provider );
   }
 }
+
+void QgsRasterPipe::evaluateDataDefinedProperties( QgsExpressionContext &context )
+{
+  if ( !mDataDefinedProperties.hasActiveProperties() )
+    return;
+
+  if ( mDataDefinedProperties.isActive( RendererOpacity ) )
+  {
+    if ( QgsRasterRenderer *r = renderer() )
+    {
+      const double prevOpacity = r->opacity();
+      context.setOriginalValueVariable( prevOpacity * 100 );
+      bool ok = false;
+      const double opacity = mDataDefinedProperties.valueAsDouble( RendererOpacity, context, prevOpacity, &ok ) / 100;
+      if ( ok )
+      {
+        r->setOpacity( opacity );
+      }
+    }
+  }
+}
+
+QgsPropertiesDefinition QgsRasterPipe::sPropertyDefinitions;
+
+void QgsRasterPipe::initPropertyDefinitions()
+{
+  const QString origin = QStringLiteral( "raster" );
+
+  sPropertyDefinitions = QgsPropertiesDefinition
+  {
+    { QgsRasterPipe::RendererOpacity, QgsPropertyDefinition( "RendererOpacity", QObject::tr( "Renderer opacity" ), QgsPropertyDefinition::Opacity, origin ) },
+  };
+}
+
+QgsPropertiesDefinition QgsRasterPipe::propertyDefinitions()
+{
+  static std::once_flag initialized;
+  std::call_once( initialized, [ = ]( )
+  {
+    initPropertyDefinitions();
+  } );
+  return sPropertyDefinitions;
+}

src/core/raster/qgsrasterpipe.h

@@ -21,6 +21,8 @@
 #include "qgis_core.h"
 #include "qgis_sip.h"
 #include "qgis.h"
+#include "qgspropertycollection.h"
+
 #include <QImage>
 #include <QMap>
 #include <QObject>
@@ -48,6 +50,15 @@ class CORE_EXPORT QgsRasterPipe
 {
   public:
 
+    /**
+     * Data definable properties.
+     * \since QGIS 3.22
+     */
+    enum Property
+    {
+      RendererOpacity, //!< Raster renderer global opacity
+    };
+
     /**
      * Constructor for an empty QgsRasterPipe.
      */
@@ -213,6 +224,48 @@ class CORE_EXPORT QgsRasterPipe
      */
     Qgis::RasterResamplingStage resamplingStage() const { return mResamplingStage; }
 
+    /**
+     * Returns a reference to the pipe's property collection, used for data defined overrides.
+     * \see setDataDefinedProperties()
+     * \since QGIS 3.22
+     */
+    QgsPropertyCollection &dataDefinedProperties() { return mDataDefinedProperties; }
+
+    /**
+     * Returns a reference to the pipe's property collection, used for data defined overrides.
+     * \see setDataDefinedProperties()
+     * \see Property
+     * \note not available in Python bindings
+     * \since QGIS 3.22
+     */
+    const QgsPropertyCollection &dataDefinedProperties() const SIP_SKIP { return mDataDefinedProperties; }
+
+    /**
+     * Sets the pipe's property \a collection, used for data defined overrides.
+     *
+     * Any existing properties will be discarded.
+     *
+     * \see dataDefinedProperties()
+     * \see Property
+     * \since QGIS 3.22
+     */
+    void setDataDefinedProperties( const QgsPropertyCollection &collection ) { mDataDefinedProperties = collection; }
+
+    /**
+     * Evalutes any data defined properties set on the pipe, applying their results
+     * to the corresponding interfaces in place.
+     *
+     * \since QGIS 3.22
+     */
+    void evaluateDataDefinedProperties( QgsExpressionContext &context );
+
+    /**
+     * Returns the definitions for data defined properties available for use in raster pipes.
+     *
+     * \since QGIS 3.22
+     */
+    static QgsPropertiesDefinition propertyDefinitions();
+
   private:
 #ifdef SIP_RUN
     QgsRasterPipe( const QgsRasterPipe &pipe );
@@ -245,6 +298,14 @@ class CORE_EXPORT QgsRasterPipe
     bool connect( QVector<QgsRasterInterface *> interfaces );
 
     Qgis::RasterResamplingStage mResamplingStage = Qgis::RasterResamplingStage::ResampleFilter;
+
+    //! Property collection for data defined raster pipe settings
+    QgsPropertyCollection mDataDefinedProperties;
+
+    //! Property definitions
+    static QgsPropertiesDefinition sPropertyDefinitions;
+
+    static void initPropertyDefinitions();
 };
 
 #endif

tests/src/python/CMakeLists.txt

@@ -256,6 +256,7 @@ ADD_PYTHON_TEST(PyQgsRasterFileWriterTask test_qgsrasterfilewritertask.py)
 ADD_PYTHON_TEST(PyQgsRasterLayer test_qgsrasterlayer.py)
 ADD_PYTHON_TEST(PyQgsRasterLayerRenderer test_qgsrasterlayerrenderer.py)
 ADD_PYTHON_TEST(PyQgsRasterColorRampShader test_qgsrastercolorrampshader.py)
+ADD_PYTHON_TEST(PyQgsRasterPipe test_qgsrasterpipe.py)
 ADD_PYTHON_TEST(PyQgsRasterRange test_qgsrasterrange.py)
 ADD_PYTHON_TEST(PyQgsRasterRendererUtils test_qgsrasterrendererutils.py)
 ADD_PYTHON_TEST(PyQgsRasterResampler test_qgsrasterresampler.py)

tests/src/python/test_qgsrasterlayer.py

@@ -55,7 +55,11 @@ from qgis.core import (Qgis,
                        QgsRasterHistogram,
                        QgsCubicRasterResampler,
                        QgsBilinearRasterResampler,
-                       QgsLayerDefinition
+                       QgsLayerDefinition,
+                       QgsRasterPipe,
+                       QgsProperty,
+                       QgsExpressionContext,
+                       QgsExpressionContextScope
                        )
 from utilities import unitTestDataPath
 from qgis.testing import start_app, unittest
@@ -1434,6 +1438,59 @@ class TestQgsRasterLayerTransformContext(unittest.TestCase):
         self.assertTrue(
             rl.transformContext().hasTransform(QgsCoordinateReferenceSystem('EPSG:4326'), QgsCoordinateReferenceSystem('EPSG:3857')))
 
+    def test_save_restore_pipe_data_defined_settings(self):
+        """
+        Test that raster pipe data defined settings are correctly saved/restored along with the layer
+        """
+        rl = QgsRasterLayer(self.rpath, 'raster')
+        rl.pipe().dataDefinedProperties().setProperty(QgsRasterPipe.RendererOpacity, QgsProperty.fromExpression('100/2'))
+
+        doc = QDomDocument()
+        layer_elem = doc.createElement("maplayer")
+        self.assertTrue(rl.writeLayerXml(layer_elem, doc, QgsReadWriteContext()))
+
+        rl2 = QgsRasterLayer(self.rpath, 'raster')
+        self.assertEqual(rl2.pipe().dataDefinedProperties().property(QgsRasterPipe.RendererOpacity),
+                         QgsProperty())
+
+        self.assertTrue(rl2.readXml(layer_elem, QgsReadWriteContext()))
+        self.assertEqual(rl2.pipe().dataDefinedProperties().property(QgsRasterPipe.RendererOpacity),
+                         QgsProperty.fromExpression('100/2'))
+
+    def test_render_data_defined_opacity(self):
+        path = os.path.join(unitTestDataPath('raster'),
+                            'band1_float32_noct_epsg4326.tif')
+        raster_layer = QgsRasterLayer(path, 'test')
+        self.assertTrue(raster_layer.isValid())
+
+        renderer = QgsSingleBandGrayRenderer(raster_layer.dataProvider(), 1)
+        raster_layer.setRenderer(renderer)
+        raster_layer.setContrastEnhancement(
+            QgsContrastEnhancement.StretchToMinimumMaximum,
+            QgsRasterMinMaxOrigin.MinMax)
+
+        raster_layer.pipe().dataDefinedProperties().setProperty(QgsRasterPipe.RendererOpacity, QgsProperty.fromExpression('@layer_opacity'))
+
+        ce = raster_layer.renderer().contrastEnhancement()
+        ce.setMinimumValue(-3.3319999287625854e+38)
+        ce.setMaximumValue(3.3999999521443642e+38)
+
+        map_settings = QgsMapSettings()
+        map_settings.setLayers([raster_layer])
+        map_settings.setExtent(raster_layer.extent())
+
+        context = QgsExpressionContext()
+        scope = QgsExpressionContextScope()
+        scope.setVariable('layer_opacity', 50)
+        context.appendScope(scope)
+        map_settings.setExpressionContext(context)
+
+        checker = QgsRenderChecker()
+        checker.setControlName("expected_raster_data_defined_opacity")
+        checker.setMapSettings(map_settings)
+
+        self.assertTrue(checker.runTest("raster_data_defined_opacity"))
+
 
 if __name__ == '__main__':
     unittest.main()

tests/src/python/test_qgsrasterpipe.py

@@ -0,0 +1,62 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    test_qgsrasterpipe.py
+    ---------------------
+    Date                 : June 2021
+    Copyright            : (C) 2021 by Nyall Dawson
+    Email                : nyall dot dawson at gmail dot 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.                                   *
+*                                                                         *
+***************************************************************************
+
+From build dir, run: ctest -R PyQgsRasterPipe\$ -V
+
+"""
+
+__author__ = 'Nyall Dawson'
+__date__ = 'June 2021'
+__copyright__ = '(C) 2021, Nyall Dawson'
+
+import qgis  # NOQA
+from qgis.core import (QgsRasterPipe,
+                       QgsProperty,
+                       QgsExpressionContext,
+                       QgsSingleBandPseudoColorRenderer
+                       )
+from qgis.testing import start_app, unittest
+
+from utilities import unitTestDataPath
+
+# Convenience instances in case you may need them
+# not used in this test
+start_app()
+TEST_DATA_DIR = unitTestDataPath()
+
+
+class TestQgsRasterPipe(unittest.TestCase):
+
+    def test_data_defined_properties(self):
+        pipe = QgsRasterPipe()
+
+        pipe.dataDefinedProperties().setProperty(QgsRasterPipe.RendererOpacity, QgsProperty.fromExpression('100/2'))
+        self.assertEqual(pipe.dataDefinedProperties().property(QgsRasterPipe.RendererOpacity),
+                         QgsProperty.fromExpression('100/2'))
+
+        pipe.set(QgsSingleBandPseudoColorRenderer(None))
+        self.assertTrue(pipe.renderer())
+        self.assertEqual(pipe.renderer().opacity(), 1.0)
+
+        # apply properties to pipe
+        pipe.evaluateDataDefinedProperties(QgsExpressionContext())
+        self.assertEqual(pipe.renderer().opacity(), 0.5)
+
+
+if __name__ == '__main__':
+    unittest.main()