Switch some composer expressions to contexts

qgis · Aug 22, 2015 · a0e35a3 · a0e35a3
1 parent f9a7820
commit a0e35a3
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Showing 15 changed files with 470 additions and 26 deletions.
diff --git a/python/core/composer/qgscomposeritem.sip b/python/core/composer/qgscomposeritem.sip
@@ -630,6 +630,12 @@ class QgsComposerItem : QgsComposerObject, QGraphicsRectItem
     */
     void setCurrentExportLayer( const int layerIdx = -1 );
 
+    /** Creates an expression context relating to the item's current state. The context includes
+     * scopes for global, project, composition, atlas and item properties.
+     * @note added in QGIS 2.12
+     */
+    QgsExpressionContext* createExpressionContext() const /Factory/;
+
   public slots:
     /** Sets the item rotation
      * @deprecated Use setItemRotation( double rotation ) instead

diff --git a/python/core/qgsexpressioncontext.sip b/python/core/qgsexpressioncontext.sip
@@ -404,6 +404,56 @@ class QgsExpressionContextUtils
      */
     static void setLayerVariables( QgsMapLayer* layer, const QgsStringMap variables );
 
+    /** Creates a new scope which contains variables and functions relating to a QgsComposition.
+     * For instance, number of pages and page sizes.
+     * @param composition source composition
+     */
+    static QgsExpressionContextScope* compositionScope( const QgsComposition *composition ) /Factory/;
+
+    /** Sets a composition context variable. This variable will be contained within scopes retrieved via
+     * compositionScope().
+     * @param composition target composition
+     * @param name variable name
+     * @param value variable value
+     * @see setCompositionVariables()
+     * @see compositionScope()
+     */
+    static void setCompositionVariable( QgsComposition* composition, const QString& name, const QVariant& value );
+
+    /** Sets all composition context variables. Existing composition variables will be removed and replaced
+     * with the variables specified.
+     * @param composition target composition
+     * @param variables new set of layer variables
+     * @see setCompositionVariable()
+     * @see compositionScope()
+     */
+    static void setCompositionVariables( QgsComposition* composition, const QgsStringMap variables );
+
+    /** Creates a new scope which contains variables and functions relating to a QgsComposerItem.
+     * For instance, item size and position.
+     * @param composerItem source composer item
+     */
+    static QgsExpressionContextScope* composerItemScope( const QgsComposerItem *composerItem ) /Factory/;
+
+    /** Sets a composer item context variable. This variable will be contained within scopes retrieved via
+     * composerItemScope().
+     * @param composerItem target composer item
+     * @param name variable name
+     * @param value variable value
+     * @see setComposerItemVariables()
+     * @see composerItemScope()
+     */
+    static void setComposerItemVariable( QgsComposerItem* composerItem, const QString& name, const QVariant& value );
+
+    /** Sets all composition context variables. Existing compositoin variables will be removed and replaced
+     * with the variables specified.
+     * @param composerItem target composer item
+     * @param variables new set of layer variables
+     * @see setComposerItemVariable()
+     * @see composerItemScope()
+     */
+    static void setComposerItemVariables( QgsComposerItem* composerItem, const QgsStringMap variables );
+
     /** Registers all known core functions provided by QgsExpressionContextScope objects.
      */
     static void registerContextFunctions();

diff --git a/src/app/composer/qgscomposeritemwidget.cpp b/src/app/composer/qgscomposeritemwidget.cpp
@@ -22,6 +22,7 @@
 #include "qgscomposition.h"
 #include "qgspoint.h"
 #include "qgsdatadefinedbutton.h"
+#include "qgsexpressioncontext.h"
 #include <QColorDialog>
 #include <QPen>
 
@@ -140,6 +141,13 @@ QgsComposerItemWidget::QgsComposerItemWidget( QWidget* parent, QgsComposerItem*
 
   connect( mTransparencySlider, SIGNAL( valueChanged( int ) ), mTransparencySpnBx, SLOT( setValue( int ) ) );
 
+  QgsExpressionContext* context = mItem->createExpressionContext();
+  mVariableEditor->setContext( context );
+  mVariableEditor->setEditableScopeIndex( context->scopeCount() - 1 );
+  delete context;
+
+  connect( mVariableEditor, SIGNAL( scopeChanged() ), this, SLOT( variablesChanged() ) );
+
   //connect atlas signals to data defined buttons
   QgsAtlasComposition* atlas = atlasComposition();
   if ( atlas )
@@ -260,6 +268,11 @@ void QgsComposerItemWidget::changeItemPosition()
   mItem->endCommand();
 }
 
+void QgsComposerItemWidget::variablesChanged()
+{
+  QgsExpressionContextUtils::setComposerItemVariables( mItem, mVariableEditor->variablesInActiveScope() );
+}
+
 QgsComposerItem::ItemPositionMode QgsComposerItemWidget::positionMode() const
 {
   if ( mUpperLeftCheckBox->checkState() == Qt::Checked )

diff --git a/src/app/composer/qgscomposeritemwidget.h b/src/app/composer/qgscomposeritemwidget.h
@@ -139,6 +139,11 @@ class QgsComposerItemWidget: public QgsComposerItemBaseWidget, private Ui::QgsCo
 //    void changeItemTransparency( int value );
     void changeItemPosition();
 
+  private slots:
+
+    void variablesChanged();
+
+
 };
 
 #endif //QGSCOMPOSERITEMWIDGET_H
diff --git a/src/app/composer/qgscompositionwidget.cpp b/src/app/composer/qgscompositionwidget.cpp
@@ -22,6 +22,7 @@
 #include "qgsstylev2.h"
 #include "qgssymbolv2selectordialog.h"
 #include "qgssymbollayerv2utils.h"
+#include "qgsexpressioncontext.h"
 #include <QColorDialog>
 #include <QWidget>
 #include <QPrinter> //for screen resolution
@@ -44,6 +45,14 @@ QgsCompositionWidget::QgsCompositionWidget( QWidget* parent, QgsComposition* c )
   //read with/height from composition and find suitable entries to display
   displayCompositionWidthHeight();
 
+  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::globalScope() );
+  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::projectScope() );
+  mVariableEditor->context()->appendScope( QgsExpressionContextUtils::compositionScope( mComposition ) );
+  mVariableEditor->reloadContext();
+  mVariableEditor->setEditableScopeIndex( 2 );
+
+  connect( mVariableEditor, SIGNAL( scopeChanged() ), this, SLOT( variablesChanged() ) );
+
   if ( mComposition )
   {
     mNumPagesSpinBox->setValue( mComposition->numPages() );
@@ -170,6 +179,11 @@ void QgsCompositionWidget::populateDataDefinedButtons()
   mPaperOrientationDDBtn->blockSignals( false );
 }
 
+void QgsCompositionWidget::variablesChanged()
+{
+  QgsExpressionContextUtils::setCompositionVariables( mComposition, mVariableEditor->variablesInActiveScope() );
+}
+
 void QgsCompositionWidget::setDataDefinedProperty( const QgsDataDefinedButton* ddBtn, QgsComposerObject::DataDefinedProperty property )
 {
   if ( !mComposition )

diff --git a/src/app/composer/qgscompositionwidget.h b/src/app/composer/qgscompositionwidget.h
@@ -83,6 +83,8 @@ class QgsCompositionWidget: public QWidget, private Ui::QgsCompositionWidgetBase
     /** Initializes data defined buttons to current atlas coverage layer*/
     void populateDataDefinedButtons();
 
+    void variablesChanged();
+
   private:
     QgsComposition* mComposition;
     QMap<QString, QgsCompositionPaper> mPaperMap;

diff --git a/src/core/composer/qgsatlascomposition.cpp b/src/core/composer/qgsatlascomposition.cpp
@@ -27,6 +27,7 @@
 #include "qgsmaplayerregistry.h"
 #include "qgsproject.h"
 #include "qgsmessagelog.h"
+#include "qgsexpressioncontext.h"
 
 QgsAtlasComposition::QgsAtlasComposition( QgsComposition* composition )
     : mComposition( composition )
@@ -218,6 +219,8 @@ int QgsAtlasComposition::updateFeatures()
     return 0;
   }
 
+  QgsExpressionContext expressionContext = createExpressionContext();
+
   updateFilenameExpression();
 
   // select all features with all attributes
@@ -248,7 +251,7 @@ int QgsAtlasComposition::updateFeatures()
     {
       nameExpression.reset( 0 );
     }
-    nameExpression->prepare( mCoverageLayer->pendingFields() );
+    nameExpression->prepare( &expressionContext );
   }
 
   // We cannot use nextFeature() directly since the feature pointer is rewinded by the rendering process
@@ -260,10 +263,12 @@ int QgsAtlasComposition::updateFeatures()
 
   while ( fit.nextFeature( feat ) )
   {
+    expressionContext.setFeature( feat );
+
     QString pageName;
     if ( !nameExpression.isNull() )
     {
-      QVariant result = nameExpression->evaluate( &feat, mCoverageLayer->fields() );
+      QVariant result = nameExpression->evaluate( &expressionContext );
       if ( nameExpression->hasEvalError() )
       {
         QgsMessageLog::logMessage( tr( "Atlas name eval error: %1" ).arg( nameExpression->evalErrorString() ), tr( "Composer" ) );
@@ -446,13 +451,15 @@ bool QgsAtlasComposition::prepareForFeature( const int featureI, const bool upda
   // retrieve the next feature, based on its id
   mCoverageLayer->getFeatures( QgsFeatureRequest().setFilterFid( mFeatureIds[ featureI ].first ) ).nextFeature( mCurrentFeature );
 
+  QgsExpressionContext expressionContext = createExpressionContext();
+
   QgsExpression::setSpecialColumn( "$atlasfeatureid", mCurrentFeature.id() );
   QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( *mCurrentFeature.constGeometry() ) );
   QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( mCurrentFeature ) );
   QgsExpression::setSpecialColumn( "$feature", QVariant(( int )featureI + 1 ) );
 
   // generate filename for current feature
-  if ( !evalFeatureFilename() )
+  if ( !evalFeatureFilename( expressionContext ) )
   {
     //error evaluating filename
     return false;
@@ -820,14 +827,31 @@ bool QgsAtlasComposition::setFilenamePattern( const QString& pattern )
   return updateFilenameExpression();
 }
 
+QgsExpressionContext QgsAtlasComposition::createExpressionContext()
+{
+  QgsExpressionContext expressionContext;
+  expressionContext << QgsExpressionContextUtils::globalScope()
+  << QgsExpressionContextUtils::projectScope();
+  if ( mComposition )
+    expressionContext << QgsExpressionContextUtils::compositionScope( mComposition );
+
+  expressionContext << new QgsExpressionContextScope( "Atlas" );
+  if ( mCoverageLayer )
+    expressionContext.lastScope()->setFields( mCoverageLayer->fields() );
+  if ( mComposition->atlasMode() != QgsComposition::AtlasOff )
+    expressionContext.lastScope()->setFeature( mCurrentFeature );
+
+  return expressionContext;
+}
+
 bool QgsAtlasComposition::updateFilenameExpression()
 {
   if ( !mCoverageLayer )
   {
     return false;
   }
 
-  const QgsFields& fields = mCoverageLayer->fields();
+  QgsExpressionContext expressionContext = createExpressionContext();
 
   if ( mFilenamePattern.size() > 0 )
   {
@@ -841,23 +865,23 @@ bool QgsAtlasComposition::updateFilenameExpression()
     }
 
     // prepare the filename expression
-    mFilenameExpr->prepare( fields );
+    mFilenameExpr->prepare( &expressionContext );
   }
 
   //if atlas preview is currently enabled, regenerate filename for current feature
   if ( mComposition->atlasMode() == QgsComposition::PreviewAtlas )
   {
-    evalFeatureFilename();
+    evalFeatureFilename( expressionContext );
   }
   return true;
 }
 
-bool QgsAtlasComposition::evalFeatureFilename()
+bool QgsAtlasComposition::evalFeatureFilename( const QgsExpressionContext &context )
 {
   //generate filename for current atlas feature
   if ( mFilenamePattern.size() > 0 && !mFilenameExpr.isNull() )
   {
-    QVariant filenameRes = mFilenameExpr->evaluate( &mCurrentFeature, mCoverageLayer->fields() );
+    QVariant filenameRes = mFilenameExpr->evaluate( &context );
     if ( mFilenameExpr->hasEvalError() )
     {
       QgsMessageLog::logMessage( tr( "Atlas filename evaluation error: %1" ).arg( mFilenameExpr->evalErrorString() ), tr( "Composer" ) );

diff --git a/src/core/composer/qgsatlascomposition.h b/src/core/composer/qgsatlascomposition.h
@@ -29,6 +29,7 @@ class QgsComposerMap;
 class QgsComposition;
 class QgsVectorLayer;
 class QgsExpression;
+class QgsExpressionContext;
 
 /** \ingroup MapComposer
  * Class used to render an Atlas, iterating over geometry features.
@@ -338,7 +339,7 @@ class CORE_EXPORT QgsAtlasComposition : public QObject
     /** Evaluates filename for current feature
      * @returns true if feature filename was successfully evaluated
     */
-    bool evalFeatureFilename();
+    bool evalFeatureFilename( const QgsExpressionContext &context );
 
     QgsComposition* mComposition;
 
@@ -396,6 +397,8 @@ class CORE_EXPORT QgsAtlasComposition : public QObject
     //computes the extent of the current feature, in the crs of the specified map
     void computeExtent( QgsComposerMap *map );
 
+    QgsExpressionContext createExpressionContext();
+
     //list of predefined scales
     QVector<qreal> mPredefinedScales;
 };

diff --git a/src/core/composer/qgscomposeritem.cpp b/src/core/composer/qgscomposeritem.cpp
@@ -40,6 +40,7 @@
 #include "qgslogger.h"
 #include "qgssymbollayerv2utils.h" //for pointOnLineWithDistance
 #include "qgsmaprenderer.h" //for getCompositionMode
+#include "qgsexpressioncontext.h"
 
 #include <cmath>
 
@@ -846,6 +847,24 @@ bool QgsComposerItem::shouldDrawItem() const
   return !mEvaluatedExcludeFromExports;
 }
 
+QgsExpressionContext* QgsComposerItem::createExpressionContext() const
+{
+  QgsExpressionContext* context = new QgsExpressionContext();
+  context->appendScope( QgsExpressionContextUtils::globalScope() );
+  context->appendScope( QgsExpressionContextUtils::projectScope() );
+  if ( mComposition )
+  {
+    context->appendScope( QgsExpressionContextUtils::compositionScope( mComposition ) );
+    if ( mComposition->atlasComposition().enabled() )
+    {
+      context->appendScope( QgsExpressionContextUtils::atlasScope( &mComposition->atlasComposition() ) );
+    }
+  }
+
+  context->appendScope( QgsExpressionContextUtils::composerItemScope( this ) );
+  return context;
+}
+
 void QgsComposerItem::drawBackground( QPainter* p )
 {
   if ( mBackground && p )

diff --git a/src/core/composer/qgscomposeritem.h b/src/core/composer/qgscomposeritem.h
@@ -31,6 +31,7 @@ class QGraphicsLineItem;
 class QgsComposerItemGroup;
 class QgsDataDefined;
 class QgsComposition;
+class QgsExpressionContext;
 
 /** \ingroup MapComposer
  * A item that forms part of a map composition.
@@ -582,6 +583,12 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
     */
     virtual void setCurrentExportLayer( const int layerIdx = -1 ) { mCurrentExportLayer = layerIdx; }
 
+    /** Creates an expression context relating to the item's current state. The context includes
+     * scopes for global, project, composition, atlas and item properties.
+     * @note added in QGIS 2.12
+     */
+    QgsExpressionContext* createExpressionContext() const;
+
   public slots:
     /** Sets the item rotation
      * @deprecated Use setItemRotation( double rotation ) instead