[FEATURE][composer] Custom format for grid annotations (fix #9292)

Allows composer map grid annotations in custom formats which are
evaluated using QgsExpressions. Made possible through the use
of Expression Contexts(tm)!

Author: nyalldawson

python/core/composer/qgscomposermapgrid.sip

@@ -182,9 +182,10 @@ class QgsComposerMapGrid : QgsComposerMapItem
       DegreeMinuteSecond, /*!< degree/minutes/seconds, use NSEW suffix */
       DecimalWithSuffix, /*!< decimal degrees, use NSEW suffix */
       DegreeMinuteNoSuffix, /*!< degree/minutes, use - for S/W coordinates */
-      DegreeMinutePadded, /*!< degree/minutes, with minutes using leading zeros were required */
+      DegreeMinutePadded, /*!< degree/minutes, with minutes using leading zeros where required */
       DegreeMinuteSecondNoSuffix, /*!< degree/minutes/seconds, use - for S/W coordinates */
-      DegreeMinuteSecondPadded /*!< degree/minutes/seconds, with minutes using leading zeros were required */
+      DegreeMinuteSecondPadded, /*!< degree/minutes/seconds, with minutes using leading zeros where required */
+      CustomFormat /*!< custom expression-based format */
     };
 
     /** Border sides for annotations
@@ -586,6 +587,22 @@ class QgsComposerMapGrid : QgsComposerMapItem
     */
     AnnotationFormat annotationFormat() const;
 
+    /** Sets the expression used for drawing grid annotations. This is only used when annotationFormat()
+     * is QgsComposerMapGrid::CustomFormat.
+     * @param expression expression for evaluating custom grid annotations
+     * @see annotationExpression
+     * @note added in QGIS 2.12
+    */
+    void setAnnotationExpression( const QString& expression );
+
+    /** Returns the expression used for drawing grid annotations. This is only used when annotationFormat()
+     * is QgsComposerMapGrid::CustomFormat.
+     * @returns expression for evaluating custom grid annotations
+     * @see setAnnotationExpression
+     * @note added in QGIS 2.12
+    */
+    QString annotationExpression() const;
+
     //
     // GRID FRAME
     //
@@ -735,4 +752,6 @@ class QgsComposerMapGrid : QgsComposerMapItem
     */
     QColor frameFillColor2() const;
 
+    virtual QgsExpressionContext* createExpressionContext() const;
+
 };

src/app/composer/qgscomposermapwidget.cpp

@@ -74,14 +74,15 @@ QgsComposerMapWidget::QgsComposerMapWidget( QgsComposerMap* composerMap )
   insertFrameDisplayEntries( mFrameDivisionsTopComboBox );
   insertFrameDisplayEntries( mFrameDivisionsBottomComboBox );
 
-  mAnnotationFormatComboBox->insertItem( 0, tr( "Decimal" ) );
-  mAnnotationFormatComboBox->insertItem( 1, tr( "Decimal with suffix" ) );
-  mAnnotationFormatComboBox->insertItem( 2, tr( "Degree, minute" ) );
-  mAnnotationFormatComboBox->insertItem( 3, tr( "Degree, minute with suffix" ) );
-  mAnnotationFormatComboBox->insertItem( 4, tr( "Degree, minute aligned" ) );
-  mAnnotationFormatComboBox->insertItem( 5, tr( "Degree, minute, second" ) );
-  mAnnotationFormatComboBox->insertItem( 6, tr( "Degree, minute, second with suffix" ) );
-  mAnnotationFormatComboBox->insertItem( 7, tr( "Degree, minute, second aligned" ) );
+  mAnnotationFormatComboBox->addItem( tr( "Decimal" ), QgsComposerMapGrid::Decimal );
+  mAnnotationFormatComboBox->addItem( tr( "Decimal with suffix" ), QgsComposerMapGrid::DecimalWithSuffix );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute" ), QgsComposerMapGrid::DegreeMinuteNoSuffix );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute with suffix" ), QgsComposerMapGrid::DegreeMinute );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute aligned" ), QgsComposerMapGrid::DegreeMinutePadded );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute, second" ), QgsComposerMapGrid::DegreeMinuteSecondNoSuffix );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute, second with suffix" ), QgsComposerMapGrid::DegreeMinuteSecond );
+  mAnnotationFormatComboBox->addItem( tr( "Degree, minute, second aligned" ), QgsComposerMapGrid::DegreeMinuteSecondPadded );
+  mAnnotationFormatComboBox->addItem( tr( "Custom" ), QgsComposerMapGrid::CustomFormat );
 
   mAnnotationFontColorButton->setColorDialogTitle( tr( "Select font color" ) );
   mAnnotationFontColorButton->setAllowAlpha( true );
@@ -1494,34 +1495,8 @@ void QgsComposerMapWidget::setGridItems( const QgsComposerMapGrid* grid )
 
   mAnnotationFontColorButton->setColor( grid->annotationFontColor() );
 
-  //mAnnotationFormatComboBox
-  switch ( grid->annotationFormat() )
-  {
-    case QgsComposerMapGrid::Decimal:
-      mAnnotationFormatComboBox->setCurrentIndex( 0 );
-      break;
-    case QgsComposerMapGrid::DegreeMinute:
-      mAnnotationFormatComboBox->setCurrentIndex( 3 );
-      break;
-    case QgsComposerMapGrid::DegreeMinuteSecond:
-      mAnnotationFormatComboBox->setCurrentIndex( 6 );
-      break;
-    case QgsComposerMapGrid::DecimalWithSuffix:
-      mAnnotationFormatComboBox->setCurrentIndex( 1 );
-      break;
-    case QgsComposerMapGrid::DegreeMinuteNoSuffix:
-      mAnnotationFormatComboBox->setCurrentIndex( 2 );
-      break;
-    case QgsComposerMapGrid::DegreeMinutePadded:
-      mAnnotationFormatComboBox->setCurrentIndex( 4 );
-      break;
-    case QgsComposerMapGrid::DegreeMinuteSecondNoSuffix:
-      mAnnotationFormatComboBox->setCurrentIndex( 5 );
-      break;
-    case QgsComposerMapGrid::DegreeMinuteSecondPadded:
-      mAnnotationFormatComboBox->setCurrentIndex( 7 );
-      break;
-  }
+  mAnnotationFormatComboBox->setCurrentIndex( mAnnotationFormatComboBox->findData( grid->annotationFormat() ) );
+  mAnnotationFormatButton->setEnabled( grid->annotationFormat() == QgsComposerMapGrid::CustomFormat );
   mDistanceToMapFrameSpinBox->setValue( grid->annotationFrameDistance() );
   mCoordinatePrecisionSpinBox->setValue( grid->annotationPrecision() );
 
@@ -2023,6 +1998,30 @@ void QgsComposerMapWidget::on_mDrawAnnotationGroupBox_toggled( bool state )
   mComposerMap->endCommand();
 }
 
+void QgsComposerMapWidget::on_mAnnotationFormatButton_clicked()
+{
+  QgsComposerMapGrid* grid = currentGrid();
+  if ( !grid )
+  {
+    return;
+  }
+
+  QScopedPointer< QgsExpressionContext> expressionContext( grid->createExpressionContext() );
+
+  QgsExpressionBuilderDialog exprDlg( 0, grid->annotationExpression(), this, "generic", *expressionContext );
+  exprDlg.setWindowTitle( tr( "Expression based annotation" ) );
+
+  if ( exprDlg.exec() == QDialog::Accepted )
+  {
+    QString expression =  exprDlg.expressionText();
+    mComposerMap->beginCommand( tr( "Annotation format changed" ) );
+    grid->setAnnotationExpression( expression );
+    mComposerMap->updateBoundingRect();
+    mComposerMap->update();
+    mComposerMap->endCommand();
+  }
+}
+
 void QgsComposerMapWidget::on_mAnnotationDisplayLeftComboBox_currentIndexChanged( const QString &text )
 {
   handleChangedAnnotationDisplay( QgsComposerMapGrid::Left, text );
@@ -2142,41 +2141,14 @@ void QgsComposerMapWidget::on_mAnnotationFormatComboBox_currentIndexChanged( int
 
   mComposerMap->beginCommand( tr( "Annotation format changed" ) );
 
-  switch ( index )
-  {
-    case 0:
-      grid->setAnnotationFormat( QgsComposerMapGrid::Decimal );
-      break;
-    case 3:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinute );
-      break;
-    case 6:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinuteSecond );
-      break;
-    case 1:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DecimalWithSuffix );
-      break;
-    case 2:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinuteNoSuffix );
-      break;
-    case 4:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinutePadded );
-      break;
-    case 5:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinuteSecondNoSuffix );
-      break;
-    case 7:
-      grid->setAnnotationFormat( QgsComposerMapGrid::DegreeMinuteSecondPadded );
-      break;
-  }
+  grid->setAnnotationFormat(( QgsComposerMapGrid::AnnotationFormat )mAnnotationFormatComboBox->itemData( index ).toInt() );
+  mAnnotationFormatButton->setEnabled( grid->annotationFormat() == QgsComposerMapGrid::CustomFormat );
 
   mComposerMap->updateBoundingRect();
   mComposerMap->update();
   mComposerMap->endCommand();
 }
 
-
-
 void QgsComposerMapWidget::on_mCoordinatePrecisionSpinBox_valueChanged( int value )
 {
   QgsComposerMapGrid* grid = currentGrid();

src/app/composer/qgscomposermapwidget.h

@@ -106,6 +106,7 @@ class QgsComposerMapWidget: public QgsComposerItemBaseWidget, private Ui::QgsCom
     void on_mFrameDivisionsBottomComboBox_currentIndexChanged( int index );
 
     void on_mDrawAnnotationGroupBox_toggled( bool state );
+    void on_mAnnotationFormatButton_clicked();
 
     //annotation display
     void on_mAnnotationDisplayLeftComboBox_currentIndexChanged( const QString& text );

src/core/composer/qgscomposermapgrid.cpp

@@ -28,6 +28,7 @@
 #include "qgscoordinatereferencesystem.h"
 #include "qgslogger.h"
 #include "qgsfontutils.h"
+#include "qgsexpressioncontext.h"
 
 #include <QPainter>
 #include <QPen>
@@ -296,6 +297,7 @@ bool QgsComposerMapGrid::writeXML( QDomElement& elem, QDomDocument& doc ) const
 
   mapGridElem.setAttribute( "annotationFormat", mGridAnnotationFormat );
   mapGridElem.setAttribute( "showAnnotation", mShowGridAnnotation );
+  mapGridElem.setAttribute( "annotationExpression", mGridAnnotationExpressionString );
   mapGridElem.setAttribute( "leftAnnotationDisplay", mLeftGridAnnotationDisplay );
   mapGridElem.setAttribute( "rightAnnotationDisplay", mRightGridAnnotationDisplay );
   mapGridElem.setAttribute( "topAnnotationDisplay", mTopGridAnnotationDisplay );
@@ -395,6 +397,8 @@ bool QgsComposerMapGrid::readXML( const QDomElement& itemElem, const QDomDocumen
   //annotation
   mShowGridAnnotation = ( itemElem.attribute( "showAnnotation", "0" ) != "0" );
   mGridAnnotationFormat = QgsComposerMapGrid::AnnotationFormat( itemElem.attribute( "annotationFormat", "0" ).toInt() );
+  mGridAnnotationExpressionString = itemElem.attribute( "annotationExpression" );
+  mGridAnnotationExpression.reset();
   mLeftGridAnnotationPosition = QgsComposerMapGrid::AnnotationPosition( itemElem.attribute( "leftAnnotationPosition", "0" ).toInt() );
   mRightGridAnnotationPosition = QgsComposerMapGrid::AnnotationPosition( itemElem.attribute( "rightAnnotationPosition", "0" ).toInt() );
   mTopGridAnnotationPosition = QgsComposerMapGrid::AnnotationPosition( itemElem.attribute( "topAnnotationPosition", "0" ).toInt() );
@@ -689,7 +693,7 @@ void QgsComposerMapGrid::draw( QPainter* p )
 
   if ( mShowGridAnnotation )
   {
-    drawCoordinateAnnotations( p, horizontalLines, verticalLines );
+    drawCoordinateAnnotations( p, horizontalLines, verticalLines, context.expressionContext() );
   }
 }
 
@@ -1037,7 +1041,7 @@ void QgsComposerMapGrid::drawGridFrameLineBorder( QPainter* p, QgsComposerMapGri
   }
 }
 
-void QgsComposerMapGrid::drawCoordinateAnnotations( QPainter* p, const QList< QPair< double, QLineF > >& hLines, const QList< QPair< double, QLineF > >& vLines ) const
+void QgsComposerMapGrid::drawCoordinateAnnotations( QPainter* p, const QList< QPair< double, QLineF > >& hLines, const QList< QPair< double, QLineF > >& vLines, QgsExpressionContext &expressionContext ) const
 {
   if ( !p )
   {
@@ -1048,15 +1052,15 @@ void QgsComposerMapGrid::drawCoordinateAnnotations( QPainter* p, const QList< QP
   QList< QPair< double, QLineF > >::const_iterator it = hLines.constBegin();
   for ( ; it != hLines.constEnd(); ++it )
   {
-    currentAnnotationString = gridAnnotationString( it->first, QgsComposerMapGrid::Latitude );
+    currentAnnotationString = gridAnnotationString( it->first, QgsComposerMapGrid::Latitude, expressionContext );
     drawCoordinateAnnotation( p, it->second.p1(), currentAnnotationString, QgsComposerMapGrid::Latitude );
     drawCoordinateAnnotation( p, it->second.p2(), currentAnnotationString, QgsComposerMapGrid::Latitude );
   }
 
   it = vLines.constBegin();
   for ( ; it != vLines.constEnd(); ++it )
   {
-    currentAnnotationString =  gridAnnotationString( it->first, QgsComposerMapGrid::Longitude );
+    currentAnnotationString =  gridAnnotationString( it->first, QgsComposerMapGrid::Longitude, expressionContext );
     drawCoordinateAnnotation( p, it->second.p1(), currentAnnotationString, QgsComposerMapGrid::Longitude );
     drawCoordinateAnnotation( p, it->second.p2(), currentAnnotationString, QgsComposerMapGrid::Longitude );
   }
@@ -1369,7 +1373,7 @@ void QgsComposerMapGrid::drawAnnotation( QPainter* p, const QPointF& pos, int ro
   p->restore();
 }
 
-QString QgsComposerMapGrid::gridAnnotationString( double value, QgsComposerMapGrid::AnnotationCoordinate coord ) const
+QString QgsComposerMapGrid::gridAnnotationString( double value, QgsComposerMapGrid::AnnotationCoordinate coord, QgsExpressionContext &expressionContext ) const
 {
   //check if we are using degrees (ie, geographic crs)
   bool geographic = false;
@@ -1432,6 +1436,17 @@ QString QgsComposerMapGrid::gridAnnotationString( double value, QgsComposerMapGr
       return QString::number( qAbs( value ), 'f', mGridAnnotationPrecision ) + hemisphere;
     }
   }
+  else if ( mGridAnnotationFormat == CustomFormat )
+  {
+    expressionContext.lastScope()->setVariable( "grid_number", value );
+    expressionContext.lastScope()->setVariable( "grid_axis", coord == QgsComposerMapGrid::Longitude ? "x" : "y" );
+    if ( !mGridAnnotationExpression.data() )
+    {
+      mGridAnnotationExpression.reset( new QgsExpression( mGridAnnotationExpressionString ) );
+      mGridAnnotationExpression->prepare( &expressionContext );
+    }
+    return mGridAnnotationExpression->evaluate( &expressionContext ).toString();
+  }
 
   QgsPoint p;
   p.setX( coord == QgsComposerMapGrid::Longitude ? value : 0 );
@@ -2008,6 +2023,9 @@ double QgsComposerMapGrid::maxExtension() const
   }
 
   const QgsMapSettings& ms = mComposerMap->composition()->mapSettings();
+
+  QScopedPointer< QgsExpressionContext> expressionContext( createExpressionContext() );
+
   QStringList coordStrings;
   if ( mCRS.isValid() && mCRS != ms.destinationCrs() )
   {
@@ -2030,12 +2048,12 @@ double QgsComposerMapGrid::maxExtension() const
     QList< QPair< double, QPolygonF > >::const_iterator it = xGridLines.constBegin();
     for ( ; it != xGridLines.constEnd(); ++it )
     {
-      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Latitude ) );
+      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Latitude, *expressionContext ) );
     }
     it = yGridLines.constBegin();
     for ( ; it != yGridLines.constEnd(); ++it )
     {
-      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Longitude ) );
+      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Longitude, *expressionContext ) );
     }
   }
   else
@@ -2052,13 +2070,13 @@ double QgsComposerMapGrid::maxExtension() const
     QList< QPair< double, QLineF > >::const_iterator it = xLines.constBegin();
     for ( ; it != xLines.constEnd(); ++it )
     {
-      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Latitude ) );
+      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Latitude, *expressionContext ) );
     }
 
     it = yLines.constBegin();
     for ( ; it != yLines.constEnd(); ++it )
     {
-      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Longitude ) );
+      coordStrings.append( gridAnnotationString( it->first, QgsComposerMapGrid::Longitude, *expressionContext ) );
     }
   }
 
@@ -2183,6 +2201,16 @@ QgsComposerMapGrid::FrameSideFlags QgsComposerMapGrid::frameSideFlags() const
   return mGridFrameSides;
 }
 
+QgsExpressionContext* QgsComposerMapGrid::createExpressionContext() const
+{
+  QgsExpressionContext* context = QgsComposerObject::createExpressionContext();
+  context->appendScope( new QgsExpressionContextScope( tr( "Grid" ) ) );
+  context->lastScope()->setVariable( "grid_number", 0 );
+  context->lastScope()->setVariable( "grid_axis", "x" );
+  context->setHighlightedVariables( QStringList() << "grid_number" << "grid_axis" );
+  return context;
+}
+
 bool QgsComposerMapGrid::testFrameSideFlag( QgsComposerMapGrid::FrameSideFlag flag ) const
 {
   return mGridFrameSides.testFlag( flag );