[composer] Use the old line placement algorithm for arrows created in versions prior to 2.4 (fix #10457)

Author: nyalldawson

src/core/composer/qgscomposerarrow.cpp

@@ -31,6 +31,7 @@ QgsComposerArrow::QgsComposerArrow( QgsComposition* c )
     , mStartYIdx( 0 )
     , mMarkerMode( DefaultMarker )
     , mArrowColor( QColor( 0, 0, 0 ) )
+    , mBoundsBehaviour( 24 )
 {
   initGraphicsSettings();
 }
@@ -41,6 +42,7 @@ QgsComposerArrow::QgsComposerArrow( const QPointF& startPoint, const QPointF& st
     , mStopPoint( stopPoint )
     , mMarkerMode( DefaultMarker )
     , mArrowColor( QColor( 0, 0, 0 ) )
+    , mBoundsBehaviour( 24 )
 {
   mStartXIdx = mStopPoint.x() < mStartPoint.x();
   mStartYIdx = mStopPoint.y() < mStartPoint.y();
@@ -77,6 +79,11 @@ void QgsComposerArrow::paint( QPainter* painter, const QStyleOptionGraphicsItem
 
   //draw arrow
   QPen arrowPen = mPen;
+  if ( mBoundsBehaviour == 22 )
+  {
+    //if arrow was created in versions prior to 2.4, use the old rendering style
+    arrowPen.setCapStyle( Qt::FlatCap );
+  }
   arrowPen.setColor( mArrowColor );
   painter->setPen( arrowPen );
   painter->setBrush( QBrush( mArrowColor ) );
@@ -134,9 +141,17 @@ void QgsComposerArrow::drawHardcodedMarker( QPainter *p, MarkerType type )
   QBrush arrowBrush = p->brush();
   arrowBrush.setColor( mArrowColor );
   p->setBrush( arrowBrush );
-  QVector2D dir = QVector2D( mStopPoint - mStartPoint ).normalized();
-  QPointF stop = mStopPoint + ( dir * 0.5 * mArrowHeadWidth ).toPointF();
-  drawArrowHead( p, stop.x() - pos().x(), stop.y() - pos().y(), angle( mStartPoint, stop ), mArrowHeadWidth );
+  if ( mBoundsBehaviour == 22 )
+  {
+    //if arrow was created in versions prior to 2.4, use the old rendering style
+    drawArrowHead( p, mStopPoint.x() - pos().x(), mStopPoint.y() - pos().y(), angle( mStartPoint, mStopPoint ), mArrowHeadWidth );
+  }
+  else
+  {
+    QVector2D dir = QVector2D( mStopPoint - mStartPoint ).normalized();
+    QPointF stop = mStopPoint + ( dir * 0.5 * mArrowHeadWidth ).toPointF();
+    drawArrowHead( p, stop.x() - pos().x(), stop.y() - pos().y(), angle( mStartPoint, stop ), mArrowHeadWidth );
+  }
 }
 
 void QgsComposerArrow::drawSVGMarker( QPainter* p, MarkerType type, const QString &markerPath )
@@ -205,7 +220,30 @@ void QgsComposerArrow::drawSVGMarker( QPainter* p, MarkerType type, const QStrin
   r.render( &imagePainter );
 
   p->save();
-  p->translate( canvasPoint.x() , canvasPoint.y() );
+  if ( mBoundsBehaviour == 22 )
+  {
+    //if arrow was created in versions prior to 2.4, use the old rendering style
+    //rotate image fix point for backtransform
+    QPointF fixPoint;
+    if ( type == StartMarker )
+    {
+      fixPoint.setX( 0 ); fixPoint.setY( arrowHeadHeight / 2.0 );
+    }
+    else
+    {
+      fixPoint.setX( 0 ); fixPoint.setY( -arrowHeadHeight / 2.0 );
+    }
+    QPointF rotatedFixPoint;
+    double angleRad = ang / 180 * M_PI;
+    rotatedFixPoint.setX( fixPoint.x() * cos( angleRad ) + fixPoint.y() * -sin( angleRad ) );
+    rotatedFixPoint.setY( fixPoint.x() * sin( angleRad ) + fixPoint.y() * cos( angleRad ) );
+    p->translate( canvasPoint.x() - rotatedFixPoint.x() , canvasPoint.y() - rotatedFixPoint.y() );
+  }
+  else
+  {
+    p->translate( canvasPoint.x() , canvasPoint.y() );
+  }
+
   p->rotate( ang );
   p->translate( -mArrowHeadWidth / 2.0, -arrowHeadHeight / 2.0 );
 
@@ -264,20 +302,41 @@ void QgsComposerArrow::setArrowHeadWidth( double width )
 double QgsComposerArrow::computeMarkerMargin() const
 {
   double margin = 0;
-  if ( mMarkerMode == DefaultMarker )
-  {
-    margin = mPen.widthF() / std::sqrt( 2.0 ) + mArrowHeadWidth / 2.0;
-  }
-  else if ( mMarkerMode == NoMarker )
+
+  if ( mBoundsBehaviour == 22 )
   {
-    margin = mPen.widthF() / std::sqrt( 2.0 );
+    //if arrow was created in versions prior to 2.4, use the old rendering style
+    if ( mMarkerMode == DefaultMarker )
+    {
+      margin = mPen.widthF() / 2.0 + mArrowHeadWidth / 2.0;
+    }
+    else if ( mMarkerMode == NoMarker )
+    {
+      margin = mPen.widthF() / 2.0;
+    }
+    else if ( mMarkerMode == SVGMarker )
+    {
+      double maxArrowHeight = qMax( mStartArrowHeadHeight, mStopArrowHeadHeight );
+      margin = mPen.widthF() / 2 + qMax( mArrowHeadWidth / 2.0, maxArrowHeight / 2.0 );
+    }
   }
-  else if ( mMarkerMode == SVGMarker )
+  else
   {
-    double startMarkerMargin = std::sqrt( 0.25 * ( mStartArrowHeadHeight * mStartArrowHeadHeight + mArrowHeadWidth * mArrowHeadWidth ) );
-    double stopMarkerMargin = std::sqrt( 0.25 * ( mStopArrowHeadHeight * mStopArrowHeadHeight + mArrowHeadWidth * mArrowHeadWidth ) );
-    double markerMargin = qMax( startMarkerMargin, stopMarkerMargin );
-    margin = qMax( mPen.widthF() / std::sqrt( 2.0 ), markerMargin );
+    if ( mMarkerMode == DefaultMarker )
+    {
+      margin = mPen.widthF() / std::sqrt( 2.0 ) + mArrowHeadWidth / 2.0;
+    }
+    else if ( mMarkerMode == NoMarker )
+    {
+      margin = mPen.widthF() / std::sqrt( 2.0 );
+    }
+    else if ( mMarkerMode == SVGMarker )
+    {
+      double startMarkerMargin = std::sqrt( 0.25 * ( mStartArrowHeadHeight * mStartArrowHeadHeight + mArrowHeadWidth * mArrowHeadWidth ) );
+      double stopMarkerMargin = std::sqrt( 0.25 * ( mStopArrowHeadHeight * mStopArrowHeadHeight + mArrowHeadWidth * mArrowHeadWidth ) );
+      double markerMargin = qMax( startMarkerMargin, stopMarkerMargin );
+      margin = qMax( mPen.widthF() / std::sqrt( 2.0 ), markerMargin );
+    }
   }
   return margin;
 }
@@ -306,6 +365,7 @@ bool QgsComposerArrow::writeXML( QDomElement& elem, QDomDocument & doc ) const
   composerArrowElem.setAttribute( "markerMode", mMarkerMode );
   composerArrowElem.setAttribute( "startMarkerFile", mStartMarkerFile );
   composerArrowElem.setAttribute( "endMarkerFile", mEndMarkerFile );
+  composerArrowElem.setAttribute( "boundsBehaviourVersion", QString::number( mBoundsBehaviour ) );
 
   //arrow color
   QDomElement arrowColorElem = doc.createElement( "ArrowColor" );
@@ -338,6 +398,8 @@ bool QgsComposerArrow::readXML( const QDomElement& itemElem, const QDomDocument&
   setStartMarker( itemElem.attribute( "startMarkerFile", "" ) );
   setEndMarker( itemElem.attribute( "endMarkerFile", "" ) );
   mMarkerMode = QgsComposerArrow::MarkerMode( itemElem.attribute( "markerMode", "0" ).toInt() );
+  //if bounds behaviour version is not set, default to 2.2 behaviour
+  mBoundsBehaviour = itemElem.attribute( "boundsBehaviourVersion", "22" ).toInt();
 
   //arrow color
   QDomNodeList arrowColorList = itemElem.elementsByTagName( "ArrowColor" );

src/core/composer/qgscomposerarrow.h

@@ -110,8 +110,10 @@ class CORE_EXPORT QgsComposerArrow: public QgsComposerItem
     /**Default marker, no marker or svg marker*/
     MarkerMode mMarkerMode;
     QColor mArrowColor;
-
-
+    /**Indicates QGIS version to mimic bounding box behaviour for. The line placement changed in version 2.4, so a value
+     * of 22 is used to indicate that the line should be drawn using the older placement routine.
+    */
+    int mBoundsBehaviour;
 
     /**Adapts the item scene rect to contain the start point, the stop point including the arrow marker and the outline.
         Needs to be called whenever the arrow width/height, the outline with or the endpoints are changed*/