Add basic shell for widget

python/gui/gui.sip

@@ -141,6 +141,7 @@
 %Include qgsprevieweffect.sip
 %Include qgsprojectionselectionwidget.sip
 %Include qgsprojectionselector.sip
+%Include qgspropertyassistantwidget.sip
 %Include qgspropertyoverridebutton.sip
 %Include qgsquerybuilder.sip
 %Include qgsrasterformatsaveoptionswidget.sip

python/gui/qgspropertyassistantwidget.sip

@@ -0,0 +1,12 @@
+class QgsPropertyAssistantWidget : public QgsPanelWidget
+{
+%TypeHeaderCode
+  #include <qgspropertyassistantwidget.h>
+%End
+
+  public:
+
+    QgsPropertyAssistantWidget( QWidget* parent /TransferThis/ = nullptr );
+
+};
+

src/gui/CMakeLists.txt

@@ -284,6 +284,7 @@ SET(QGIS_GUI_SRCS
   qgsprevieweffect.cpp
   qgsprojectionselectionwidget.cpp
   qgsprojectionselector.cpp
+  qgspropertyassistantwidget.cpp
   qgspropertyoverridebutton.cpp
   qgsquerybuilder.cpp
   qgsrasterformatsaveoptionswidget.cpp
@@ -436,6 +437,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsprevieweffect.h
   qgsprojectionselectionwidget.h
   qgsprojectionselector.h
+  qgspropertyassistantwidget.h
   qgspropertyoverridebutton.h
   qgsquerybuilder.h
   qgsrasterformatsaveoptionswidget.h

src/gui/qgspropertyassistantwidget.cpp

@@ -0,0 +1,250 @@
+/***************************************************************************
+    qgspropertyassistantwidget.cpp
+    ------------------------------
+    begin                : February, 2017
+    copyright            : (C) 2017 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgspropertyassistantwidget.h"
+#include "qgsproject.h"
+#include "qgsmapsettings.h"
+#include "qgsvectorlayer.h"
+
+QgsPropertyAssistantWidget::QgsPropertyAssistantWidget( QWidget* parent ,
+    const QgsPropertyDefinition& definition, const QgsProperty& initialState,
+    const QgsVectorLayer* layer )
+    : QgsPanelWidget( parent )
+    , mDefinition( definition )
+    , mLayer( layer )
+{
+  setupUi( this );
+
+  layout()->setContentsMargins( 0, 0, 0, 0 );
+  layout()->setMargin( 0 );
+
+  setPanelTitle( mDefinition.description() );
+
+  mLegendPreview->hide();
+
+  minValueSpinBox->setShowClearButton( false );
+  maxValueSpinBox->setShowClearButton( false );
+
+  // TODO expression widget shouldn't require a non-const layer
+  mExpressionWidget->setLayer( const_cast< QgsVectorLayer* >( mLayer ) );
+  mExpressionWidget->setFilters( QgsFieldProxyModel::Numeric );
+  mExpressionWidget->setField( initialState.propertyType() == QgsProperty::ExpressionBasedProperty ? initialState.expressionString() : initialState.field() );
+
+  if ( initialState.transformer() )
+  {
+    minValueSpinBox->setValue( initialState.transformer()->minValue() );
+    maxValueSpinBox->setValue( initialState.transformer()->maxValue() );
+  }
+
+  connect( computeValuesButton, &QPushButton::clicked, this, &QgsPropertyAssistantWidget::computeValuesFromLayer );
+
+  switch ( definition.standardTemplate() )
+  {
+    case QgsPropertyDefinition::Size:
+    {
+      mTransformerWidget = new QgsPropertySizeAssistantWidget( this, mDefinition, initialState );
+    }
+    default:
+      break;
+  }
+
+  if ( mTransformerWidget )
+  {
+    mOutputWidget->layout()->addWidget( mTransformerWidget );
+    connect( mTransformerWidget, &QgsPropertyAbstractTransformerWidget::widgetChanged, this, &QgsPropertyAssistantWidget::widgetChanged );
+  }
+
+  connect( minValueSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertyAssistantWidget::widgetChanged );
+  connect( maxValueSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertyAssistantWidget::widgetChanged );
+  connect( mExpressionWidget, static_cast < void ( QgsFieldExpressionWidget::* )( const QString& ) > ( &QgsFieldExpressionWidget::fieldChanged ), this, &QgsPropertyAssistantWidget::widgetChanged );
+}
+
+void QgsPropertyAssistantWidget::registerExpressionContextGenerator( QgsExpressionContextGenerator* generator )
+{
+  mExpressionContextGenerator = generator;
+  mExpressionWidget->registerExpressionContextGenerator( generator );
+}
+
+void QgsPropertyAssistantWidget::updateProperty( QgsProperty& property )
+{
+  property.setActive( true );
+  if ( mExpressionWidget->isExpression() )
+    property.setExpressionString( mExpressionWidget->currentField() );
+  else
+    property.setField( mExpressionWidget->currentField() );
+
+  if ( mTransformerWidget )
+    property.setTransformer( mTransformerWidget->createTransformer( minValueSpinBox->value(), maxValueSpinBox->value() ) );
+}
+
+void QgsPropertyAssistantWidget::computeValuesFromLayer()
+{
+  if ( !mLayer )
+    return;
+
+  double minValue = 0.0;
+  double maxValue = 0.0;
+
+  if ( mExpressionWidget->isExpression() )
+  {
+    if ( !computeValuesFromExpression( mExpressionWidget->currentField(), minValue, maxValue ) )
+      return;
+  }
+  else
+  {
+    if ( !computeValuesFromField( mExpressionWidget->currentField(), minValue, maxValue ) )
+      return;
+  }
+
+  whileBlocking( minValueSpinBox )->setValue( minValue );
+  whileBlocking( maxValueSpinBox )->setValue( maxValue );
+  emit widgetChanged();
+}
+
+bool QgsPropertyAssistantWidget::computeValuesFromExpression( const QString& expression, double& minValue, double& maxValue ) const
+{
+  QgsExpression e( expression );
+
+  QgsExpressionContext context;
+  if ( mExpressionContextGenerator )
+  {
+    context = mExpressionContextGenerator->createExpressionContext();
+  }
+  else
+  {
+    context << QgsExpressionContextUtils::globalScope()
+    << QgsExpressionContextUtils::projectScope( QgsProject::instance() )
+    << QgsExpressionContextUtils::layerScope( mLayer );
+  }
+
+  if ( !e.prepare( &context ) )
+    return false;
+
+  QSet<QString> referencedCols( e.referencedColumns() );
+
+  QgsFeatureIterator fit = mLayer->getFeatures(
+                             QgsFeatureRequest().setFlags( e.needsGeometry()
+                                                           ? QgsFeatureRequest::NoFlags
+                                                           : QgsFeatureRequest::NoGeometry )
+                             .setSubsetOfAttributes( referencedCols, mLayer->fields() ) );
+
+  // create list of non-null attribute values
+  double min = DBL_MAX;
+  double max = -DBL_MAX;
+  QgsFeature f;
+  bool found = false;
+  while ( fit.nextFeature( f ) )
+  {
+    bool ok;
+    context.setFeature( f );
+    const double value = e.evaluate( &context ).toDouble( &ok );
+    if ( ok )
+    {
+      max = qMax( max, value );
+      min = qMin( min, value );
+      found = true;
+    }
+  }
+  if ( found )
+  {
+    minValue = min;
+    maxValue = max;
+  }
+  return found;
+}
+
+bool QgsPropertyAssistantWidget::computeValuesFromField( const QString& fieldName, double& minValue, double& maxValue ) const
+{
+  int fieldIndex = mLayer->fields().lookupField( fieldName );
+  if ( fieldIndex < 0 )
+  {
+    return false;
+  }
+
+  bool ok = false;
+  double minDouble = mLayer->minimumValue( fieldIndex ).toDouble( &ok );
+  if ( !ok )
+    return false;
+
+  double maxDouble = mLayer->maximumValue( fieldIndex ).toDouble( &ok );
+  if ( !ok )
+    return false;
+
+  minValue = minDouble;
+  maxValue = maxDouble;
+  return true;
+}
+
+
+//
+// QgsPropertySizeAssistantWidget
+//
+
+QgsPropertySizeAssistantWidget::QgsPropertySizeAssistantWidget( QWidget* parent, const QgsPropertyDefinition& definition, const QgsProperty& initialState )
+    : QgsPropertyAbstractTransformerWidget( parent, definition )
+{
+  setupUi( this );
+
+  layout()->setContentsMargins( 0, 0, 0, 0 );
+  layout()->setMargin( 0 );
+
+  scaleMethodComboBox->addItem( tr( "Flannery" ), QgsSizeScaleTransformer::Flannery );
+  scaleMethodComboBox->addItem( tr( "Surface" ), QgsSizeScaleTransformer::Area );
+  scaleMethodComboBox->addItem( tr( "Radius" ), QgsSizeScaleTransformer::Linear );
+  scaleMethodComboBox->addItem( tr( "Exponential" ), QgsSizeScaleTransformer::Exponential );
+
+  minSizeSpinBox->setShowClearButton( false );
+  maxSizeSpinBox->setShowClearButton( false );
+  nullSizeSpinBox->setShowClearButton( false );
+
+  if ( const QgsSizeScaleTransformer* sizeTransform = dynamic_cast< const QgsSizeScaleTransformer* >( initialState.transformer() ) )
+  {
+    minSizeSpinBox->setValue( sizeTransform->minSize() );
+    maxSizeSpinBox->setValue( sizeTransform->maxSize() );
+    nullSizeSpinBox->setValue( sizeTransform->nullSize() );
+    exponentSpinBox->setValue( sizeTransform->exponent() );
+    scaleMethodComboBox->setCurrentIndex( scaleMethodComboBox->findData( sizeTransform->type() ) );
+  }
+
+  exponentSpinBox->setEnabled( scaleMethodComboBox->currentData().toInt() == QgsSizeScaleTransformer::Exponential );
+
+  connect( minSizeSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertySizeAssistantWidget::widgetChanged );
+  connect( maxSizeSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertySizeAssistantWidget::widgetChanged );
+  connect( nullSizeSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertySizeAssistantWidget::widgetChanged );
+  connect( exponentSpinBox, static_cast < void ( QgsDoubleSpinBox::* )( double ) > ( &QgsDoubleSpinBox::valueChanged ), this, &QgsPropertySizeAssistantWidget::widgetChanged );
+  connect( scaleMethodComboBox, static_cast < void ( QComboBox::* )( int ) > ( &QComboBox::currentIndexChanged ), this, &QgsPropertySizeAssistantWidget::widgetChanged );
+  connect( scaleMethodComboBox, static_cast < void ( QComboBox::* )( int ) > ( &QComboBox::currentIndexChanged ), this,
+           [=]
+  {
+    exponentSpinBox->setEnabled( scaleMethodComboBox->currentData().toInt() == QgsSizeScaleTransformer::Exponential );
+  }
+         );
+}
+
+QgsPropertyTransformer* QgsPropertySizeAssistantWidget::createTransformer( double minValue, double maxValue ) const
+{
+  QgsSizeScaleTransformer* transformer = new QgsSizeScaleTransformer(
+    static_cast< QgsSizeScaleTransformer::ScaleType >( scaleMethodComboBox->currentData().toInt() ),
+    minValue,
+    maxValue,
+    minSizeSpinBox->value(),
+    maxSizeSpinBox->value(),
+    nullSizeSpinBox->value(),
+    exponentSpinBox->value() );
+  return transformer;
+}

src/gui/qgspropertyassistantwidget.h

@@ -0,0 +1,104 @@
+/***************************************************************************
+    qgspropertyassistantwidget.h
+    ----------------------------
+    begin                : February, 2017
+    copyright            : (C) 2017 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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#ifndef QGSPROPERTYASSISTANTWIDGET_H
+#define QGSPROPERTYASSISTANTWIDGET_H
+
+#include "qgspanelwidget.h"
+#include "ui_qgspropertyassistantwidgetbase.h"
+#include "ui_qgspropertysizeassistantwidget.h"
+#include "qgsproperty.h"
+#include "qgis_gui.h"
+
+class QgsMapCanvas;
+
+///@cond PRIVATE
+
+class GUI_EXPORT QgsPropertyAbstractTransformerWidget : public QWidget
+{
+    Q_OBJECT
+
+  public:
+
+    QgsPropertyAbstractTransformerWidget( QWidget* parent = nullptr, const QgsPropertyDefinition& definition = QgsPropertyDefinition() )
+        : QWidget( parent )
+        , mDefinition( definition )
+    {}
+
+    virtual QgsPropertyTransformer* createTransformer( double minValue, double maxValue ) const = 0;
+
+  signals:
+
+    void widgetChanged();
+
+  protected:
+
+    QgsPropertyDefinition mDefinition;
+
+};
+
+class GUI_EXPORT QgsPropertySizeAssistantWidget : public QgsPropertyAbstractTransformerWidget, private Ui::PropertySizeAssistant
+{
+    Q_OBJECT
+
+  public:
+
+    QgsPropertySizeAssistantWidget( QWidget* parent = nullptr, const QgsPropertyDefinition& definition = QgsPropertyDefinition(), const QgsProperty& initialState = QgsProperty() );
+
+    virtual QgsPropertyTransformer* createTransformer( double minValue, double maxValue ) const override;
+
+
+};
+
+///@endcond PRIVATE
+
+class GUI_EXPORT QgsPropertyAssistantWidget : public QgsPanelWidget, private Ui::PropertyAssistantBase
+{
+    Q_OBJECT
+
+  public:
+
+    QgsPropertyAssistantWidget( QWidget* parent = nullptr, const QgsPropertyDefinition& definition = QgsPropertyDefinition(),
+                                const QgsProperty& initialState = QgsProperty(),
+                                const QgsVectorLayer* layer = nullptr );
+
+    /**
+     * Register an expression context generator class that will be used to retrieve
+     * an expression context for the button when required.
+     */
+    void registerExpressionContextGenerator( QgsExpressionContextGenerator* generator );
+
+    void updateProperty( QgsProperty& property );
+
+
+  private slots:
+    void computeValuesFromLayer();
+
+  private:
+
+    QgsPropertyDefinition mDefinition;
+    const QgsVectorLayer* mLayer = nullptr;
+    QgsExpressionContextGenerator* mExpressionContextGenerator = nullptr;
+    QgsPropertyAbstractTransformerWidget* mTransformerWidget = nullptr;
+
+    bool computeValuesFromExpression( const QString& expression, double& minValue, double& maxValue ) const;
+    bool computeValuesFromField( const QString& fieldName, double& minValue, double& maxValue ) const;
+
+};
+
+
+#endif // QGSPROPERTYASSISTANTWIDGET_H