Snap to arbitrary snap lines

qgis · Feb 19, 2013 · 90461f2 · 90461f2
1 parent cb1f5c3
commit 90461f2
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Showing 3 changed files with 102 additions and 10 deletions.
diff --git a/src/core/composer/qgscomposition.cpp b/src/core/composer/qgscomposition.cpp
@@ -1064,6 +1064,57 @@ QPointF QgsComposition::alignPos( const QPointF& pos, const QgsComposerItem* exc
   return result;
 }
 
+void QgsComposition::addSnapLine( QGraphicsLineItem* line )
+{
+  addItem( line );
+  mSnapLines.push_back( line );
+}
+
+void QgsComposition::removeSnapLine( QGraphicsLineItem* line )
+{
+  removeItem( line );
+  mSnapLines.removeAll( line );
+}
+
+QGraphicsLineItem* QgsComposition::nearestSnapLine( double x, double y, double tolerance )
+{
+  bool xDirection = doubleNear( y, 0.0 );
+  double minSqrDist = DBL_MAX;
+  QGraphicsLineItem* item = 0;
+  double currentXCoord = 0;
+  double currentYCoord = 0;
+  double currentSqrDist = 0;
+  double sqrTolerance = tolerance * tolerance;
+
+  QList< QGraphicsLineItem* >::const_iterator it = mSnapLines.constBegin();
+  for ( ; it != mSnapLines.constEnd(); ++it )
+  {
+    currentXCoord = ( *it )->line().x1();
+    currentYCoord = ( *it )->line().y1();
+
+    if ( xDirection && !doubleNear( currentXCoord, 0.0 ) )
+    {
+      currentSqrDist = ( x - currentXCoord ) * ( x - currentXCoord );
+    }
+    else if ( !xDirection && !doubleNear( currentYCoord, 0.0 ) )
+    {
+      currentSqrDist = ( y - currentYCoord ) * ( y - currentYCoord );
+    }
+    else
+    {
+      continue;
+    }
+
+    if ( currentSqrDist < minSqrDist && currentSqrDist < sqrTolerance )
+    {
+      item = *it;
+      minSqrDist = currentSqrDist;
+    }
+  }
+
+  return item;
+}
+
 int QgsComposition::boundingRectOfSelectedItems( QRectF& bRect )
 {
   QList<QgsComposerItem*> selectedItems = selectedComposerItems();
@@ -1747,6 +1798,22 @@ void QgsComposition::collectAlignCoordinates( QMap< double, const QgsComposerIte
       alignCoordsY.insert( currentItem->transform().dy() + currentItem->rect().bottom(), currentItem );
     }
   }
+
+  //arbitrary snap lines
+  QList< QGraphicsLineItem* >::const_iterator sIt = mSnapLines.constBegin();
+  for ( ; sIt != mSnapLines.constEnd(); ++sIt )
+  {
+    double x = ( *sIt )->line().x1();
+    double y = ( *sIt )->line().y1();
+    if ( doubleNear( y, 0.0 ) )
+    {
+      alignCoordsX.insert( x, 0 );
+    }
+    else
+    {
+      alignCoordsY.insert( y, 0 );
+    }
+  }
 }
 
 void QgsComposition::checkNearestItem( double checkCoord, const QMap< double, const QgsComposerItem* >& alignCoords, double& smallestDiff,

diff --git a/src/core/composer/qgscomposition.h b/src/core/composer/qgscomposition.h
@@ -259,6 +259,13 @@ class CORE_EXPORT QgsComposition: public QGraphicsScene
     @return snapped position or original position if no snap*/
     QPointF alignPos( const QPointF& pos, const QgsComposerItem* excludeItem, double& alignX, double& alignY );
 
+    /**Add a custom snap line (can be horizontal or vertical)*/
+    void addSnapLine( QGraphicsLineItem* line );
+    /**Remove custom snap line*/
+    void removeSnapLine( QGraphicsLineItem* line );
+    /**Get nearest snap line*/
+    QGraphicsLineItem* nearestSnapLine( double x, double y, double tolerance );
+
     /**Allocates new item command and saves initial state in it
       @param item target item
       @param commandText descriptive command text
@@ -369,6 +376,9 @@ class CORE_EXPORT QgsComposition: public QGraphicsScene
     bool mAlignmentSnap;
     double mAlignmentSnapTolerance;
 
+    /**Arbitraty snap lines (horizontal and vertical)*/
+    QList< QGraphicsLineItem* > mSnapLines;
+
     QUndoStack mUndoStack;
 
     QgsComposerItemCommand* mActiveItemCommand;

diff --git a/src/gui/qgscomposerruler.cpp b/src/gui/qgscomposerruler.cpp
@@ -129,26 +129,41 @@ void QgsComposerRuler::setSceneTransform( const QTransform& transform )
 
 void QgsComposerRuler::mouseMoveEvent( QMouseEvent* event )
 {
-  qWarning( "QgsComposerRuler::mouseMoveEvent" );
+  //qWarning( "QgsComposerRuler::mouseMoveEvent" );
   updateMarker( event->posF() );
   setSnapLinePosition( event->posF() );
 }
 
 void QgsComposerRuler::mouseReleaseEvent( QMouseEvent* event )
 {
   Q_UNUSED( event );
-  delete mLineSnapItem;
   mLineSnapItem = 0;
 }
 
 void QgsComposerRuler::mousePressEvent( QMouseEvent* event )
 {
-  delete mLineSnapItem;
-  mLineSnapItem = 0;
-  mLineSnapItem = createLineSnapItem();
-  mComposition->addItem( mLineSnapItem );
-  setSnapLinePosition( event->posF() );
-  mLineSnapItem->show();
+  double x = 0;
+  double y = 0;
+  if ( mDirection == Horizontal )
+  {
+    x = mTransform.inverted().map( event->pos() ).x();
+  }
+  else //vertical
+  {
+    y = mTransform.inverted().map( event->pos() ).y();
+  }
+
+  QGraphicsLineItem* line = mComposition->nearestSnapLine( x, y, 2.0 );
+  if ( !line )
+  {
+    //create new snap line
+    mLineSnapItem = createLineSnapItem();
+    mComposition->addSnapLine( mLineSnapItem );
+  }
+  else
+  {
+    mLineSnapItem = line;
+  }
 }
 
 void QgsComposerRuler::setSnapLinePosition( const QPointF& pos )
@@ -161,11 +176,11 @@ void QgsComposerRuler::setSnapLinePosition( const QPointF& pos )
   QPointF transformedPt = mTransform.inverted().map( pos );
   if ( mDirection == Horizontal )
   {
-    mLineSnapItem->setLine( QLineF( transformedPt.x(), 0, transformedPt.x(), mComposition->height() ) );
+    mLineSnapItem->setLine( QLineF( transformedPt.x(), 0, transformedPt.x(), mComposition->height() - 1 ) );
   }
   else //vertical
   {
-    mLineSnapItem->setLine( QLineF( 0, transformedPt.y(), mComposition->width(), transformedPt.y() ) );
+    mLineSnapItem->setLine( QLineF( 0, transformedPt.y(), mComposition->width() - 1, transformedPt.y() ) );
   }
 }