Made layers/labels visibility more consistent

Some places forgot to make the max scale inclusive.

Author: Patrick Valsecchi

python/core/qgis.sip

@@ -235,6 +235,12 @@ class QGis
     /** Default highlight line/outline minimum width in mm.
      *  @note added in 2.3 */
     static double DEFAULT_HIGHLIGHT_MIN_WIDTH_MM;
+
+    /** Fudge factor used to compare two scales. The code is often going from scale to scale
+     *  denominator. So it looses precision and, when a limit is inclusive, can lead to errors.
+     *  To avoid that, use this factor instead of using <= or >=.
+     * @note added in 2.15*/
+    static double SCALE_PRECISION;
 };
 
 

python/core/qgslabel.sip

@@ -106,6 +106,9 @@ class QgsLabel
     void setScaleBasedVisibility( bool theVisibilityFlag );
     bool scaleBasedVisibility() const;
 
+    /** Return true if the label is visible at the given scale */
+    bool isInScaleRange( double scale ) const;
+
   private:
     QgsLabel (); // pretend that constructor is private for now
     QgsLabel( const QgsLabel& rh );

python/core/qgsmaplayer.sip

@@ -492,6 +492,11 @@ class QgsMapLayer : QObject
      */
     QgsMapLayerStyleManager* styleManager() const;
 
+    /**
+     * @returns true if the layer is visible at the given scale.
+     */
+    bool isInScaleRange( double scale ) const;
+
     /** Returns the minimum scale denominator at which the layer is visible.
      * Scale based visibility is only used if hasScaleBasedVisibility is true.
      * @returns minimum scale denominator at which the layer will render

src/core/dxf/qgsdxfexport.cpp

@@ -4109,11 +4109,10 @@ bool QgsDxfExport::layerIsScaleBasedVisible( const QgsMapLayer* layer ) const
   if ( !layer )
     return false;
 
-  if ( mSymbologyExport == QgsDxfExport::NoSymbology || !layer->hasScaleBasedVisibility() )
+  if ( mSymbologyExport == QgsDxfExport::NoSymbology )
     return true;
 
-  return layer->minimumScale() < mSymbologyScaleDenominator &&
-         layer->maximumScale() > mSymbologyScaleDenominator;
+  return layer->isInScaleRange( mSymbologyScaleDenominator );
 }
 
 QString QgsDxfExport::layerName( const QString &id, const QgsFeature &f ) const

src/core/qgis.cpp

@@ -87,6 +87,8 @@ double QGis::DEFAULT_HIGHLIGHT_BUFFER_MM = 0.5;
 
 double QGis::DEFAULT_HIGHLIGHT_MIN_WIDTH_MM = 1.0;
 
+double QGis::SCALE_PRECISION = 0.9999999999;
+
 // description strings for units
 // Order must match enum indices
 const char* QGis::qgisUnitTypes[] =

src/core/qgis.h

@@ -246,6 +246,12 @@ class CORE_EXPORT QGis
      *  @note added in 2.3 */
     static double DEFAULT_HIGHLIGHT_MIN_WIDTH_MM;
 
+    /** Fudge factor used to compare two scales. The code is often going from scale to scale
+     *  denominator. So it looses precision and, when a limit is inclusive, can lead to errors.
+     *  To avoid that, use this factor instead of using <= or >=.
+     * @note added in 2.15*/
+    static double SCALE_PRECISION;
+
   private:
     // String representation of unit types (set in qgis.cpp)
     static const char *qgisUnitTypes[];

src/core/qgslabel.cpp

@@ -1414,3 +1414,9 @@ float QgsLabel::maxScale() const
 {
   return mMaxScale;
 }
+
+bool QgsLabel::isInScaleRange( double scale ) const
+{
+  return !mScaleBasedVisibility ||
+         ( mMinScale * QGis::SCALE_PRECISION < scale && scale * QGis::SCALE_PRECISION < mMaxScale );
+}

src/core/qgslabel.h

@@ -146,6 +146,9 @@ class CORE_EXPORT QgsLabel
     void setScaleBasedVisibility( bool theVisibilityFlag );
     bool scaleBasedVisibility() const;
 
+    /** Return true if the label is visible at the given scale */
+    bool isInScaleRange( double scale ) const;
+
   private:
     /** Does the actual rendering of a label at the given point */
     void renderLabel( QgsRenderContext &renderContext, QgsPoint point,

src/core/qgsmaphittest.cpp

@@ -59,7 +59,7 @@ void QgsMapHitTest::run()
 
     if ( !mOnlyExpressions )
     {
-      if ( vl->hasScaleBasedVisibility() && ( mSettings.scale() < vl->minimumScale() || mSettings.scale() > vl->maximumScale() ) )
+      if ( !vl->isInScaleRange( mSettings.scale() ) )
       {
         mHitTest[vl] = SymbolV2Set(); // no symbols -> will not be shown
         mHitTestRuleKey[vl] = SymbolV2Set();

src/core/qgsmaplayer.cpp

@@ -925,6 +925,10 @@ void QgsMapLayer::connectNotify( const char * signal )
 } //  QgsMapLayer::connectNotify
 #endif
 
+bool QgsMapLayer::isInScaleRange( double scale ) const
+{
+  return !mScaleBasedVisibility || ( mMinScale * QGis::SCALE_PRECISION < scale && scale < mMaxScale );
+}
 
 void QgsMapLayer::toggleScaleBasedVisibility( bool theVisibilityFlag )
 {