Add option to convert units during conversion

Because pixel based units are unfriendly for hi-dpi or print layouts

python/core/auto_generated/vectortile/qgsmapboxglstyleconverter.sip.in

@@ -39,6 +39,51 @@ Returns a list of warning messages generated during the conversion.
     void clearWarnings();
 %Docstring
 Clears the list of warning messages.
+%End
+
+    QgsUnitTypes::RenderUnit targetUnit() const;
+%Docstring
+Returns the target unit type.
+
+By default this is QgsUnitTypes.RenderPixels in order to exactly match the original
+style rendering. But rendering in pixels can cause issues on hidpi displays or with print
+layouts, so setting a target unit of QgsUnitTypes.Millimeters or another real-world unit
+type is often more appropriate.
+
+.. seealso:: :py:func:`setTargetUnit`
+%End
+
+    void setTargetUnit( QgsUnitTypes::RenderUnit targetUnit );
+%Docstring
+Sets the target unit type.
+
+By default this is QgsUnitTypes.RenderPixels in order to exactly match the original
+style rendering. But rendering in pixels can cause issues on hidpi displays or with print
+layouts, so setting a target unit of QgsUnitTypes.Millimeters or another real-world unit
+type is often more appropriate.
+
+If setting to a non-pixel unit, be sure to call :py:func:`~QgsMapBoxGlStyleConversionContext.setPixelSizeConversionFactor` in order
+to setup an appropriate pixel-to-unit conversion factor to scale converted sizes
+using. E.g. if the target unit is millimeters, the size conversion factor should be
+set to a pixel-to-millimeter value.
+
+.. seealso:: :py:func:`targetUnit`
+%End
+
+    double pixelSizeConversionFactor() const;
+%Docstring
+Returns the pixel size conversion factor, used to scale the original pixel sizes
+when converting styles.
+
+.. seealso:: :py:func:`setSizeConversionFactor`
+%End
+
+    void setPixelSizeConversionFactor( double sizeConversionFactor );
+%Docstring
+Sets the pixel size conversion factor, used to scale the original pixel sizes
+when converting styles.
+
+.. seealso:: :py:func:`pixelSizeConversionFactor`
 %End
 
 };
@@ -75,7 +120,7 @@ Constructor for QgsMapBoxGlStyleConverter.
       NoLayerList,
     };
 
-    Result convert( const QVariantMap &style );
+    Result convert( const QVariantMap &style, QgsMapBoxGlStyleConversionContext *context = 0 );
 %Docstring
 Converts a JSON ``style`` map, and returns the resultant status of the conversion.
 
@@ -84,9 +129,11 @@ by calling :py:func:`~QgsMapBoxGlStyleConverter.errorMessage`.
 
 After conversion, the resultant labeling and style rules can be retrieved by calling
 :py:func:`~QgsMapBoxGlStyleConverter.renderer` or :py:func:`~QgsMapBoxGlStyleConverter.labeling` respectively.
+
+The optional ``context`` argument can be set to use a specific context during the conversion.
 %End
 
-    Result convert( const QString &style );
+    Result convert( const QString &style, QgsMapBoxGlStyleConversionContext *context = 0 );
 %Docstring
 Converts a JSON ``style`` string, and returns the resultant status of the conversion.
 
@@ -95,6 +142,8 @@ by calling :py:func:`~QgsMapBoxGlStyleConverter.errorMessage`.
 
 After conversion, the resultant labeling and style rules can be retrieved by calling
 :py:func:`~QgsMapBoxGlStyleConverter.renderer` or :py:func:`~QgsMapBoxGlStyleConverter.labeling` respectively.
+
+The optional ``context`` argument can be set to use a specific context during the conversion.
 %End
 
     QString errorMessage() const;
@@ -134,7 +183,7 @@ or ``None`` if the style could not be converted successfully.
       Opacity,
     };
 
-    void parseLayers( const QVariantList &layers );
+    void parseLayers( const QVariantList &layers, QgsMapBoxGlStyleConversionContext *context = 0 );
 %Docstring
 Parse list of ``layers`` from JSON.
 

src/core/vectortile/qgsmapboxglstyleconverter.cpp

@@ -33,19 +33,17 @@
 #include "qgsblureffect.h"
 
 
-constexpr double PIXEL_RATIO = 1;
-
 QgsMapBoxGlStyleConverter::QgsMapBoxGlStyleConverter()
 {
 }
 
-QgsMapBoxGlStyleConverter::Result QgsMapBoxGlStyleConverter::convert( const QVariantMap &style )
+QgsMapBoxGlStyleConverter::Result QgsMapBoxGlStyleConverter::convert( const QVariantMap &style, QgsMapBoxGlStyleConversionContext *context )
 {
   mError.clear();
   mWarnings.clear();
   if ( style.contains( QStringLiteral( "layers" ) ) )
   {
-    parseLayers( style.value( QStringLiteral( "layers" ) ).toList() );
+    parseLayers( style.value( QStringLiteral( "layers" ) ).toList(), context );
   }
   else
   {
@@ -55,16 +53,21 @@ QgsMapBoxGlStyleConverter::Result QgsMapBoxGlStyleConverter::convert( const QVar
   return Success;
 }
 
-QgsMapBoxGlStyleConverter::Result QgsMapBoxGlStyleConverter::convert( const QString &style )
+QgsMapBoxGlStyleConverter::Result QgsMapBoxGlStyleConverter::convert( const QString &style, QgsMapBoxGlStyleConversionContext *context )
 {
-  return convert( QgsJsonUtils::parseJson( style ).toMap() );
+  return convert( QgsJsonUtils::parseJson( style ).toMap(), context );
 }
 
 QgsMapBoxGlStyleConverter::~QgsMapBoxGlStyleConverter() = default;
 
-void QgsMapBoxGlStyleConverter::parseLayers( const QVariantList &layers )
+void QgsMapBoxGlStyleConverter::parseLayers( const QVariantList &layers, QgsMapBoxGlStyleConversionContext *context )
 {
-  QgsMapBoxGlStyleConversionContext context;
+  std::unique_ptr< QgsMapBoxGlStyleConversionContext > tmpContext;
+  if ( !context )
+  {
+    tmpContext = qgis::make_unique< QgsMapBoxGlStyleConversionContext >();
+    context = tmpContext.get();
+  }
 
   QList<QgsVectorTileBasicRendererStyle> rendererStyles;
   QList<QgsVectorTileBasicLabelingStyle> labelingStyles;
@@ -88,7 +91,7 @@ void QgsMapBoxGlStyleConverter::parseLayers( const QVariantList &layers )
     QString filterExpression;
     if ( jsonLayer.contains( QStringLiteral( "filter" ) ) )
     {
-      filterExpression = parseExpression( jsonLayer.value( QStringLiteral( "filter" ) ).toList(), context );
+      filterExpression = parseExpression( jsonLayer.value( QStringLiteral( "filter" ) ).toList(), *context );
     }
 
     QgsVectorTileBasicRendererStyle rendererStyle;
@@ -98,15 +101,15 @@ void QgsMapBoxGlStyleConverter::parseLayers( const QVariantList &layers )
     bool hasLabelingStyle = false;
     if ( layerType == QLatin1String( "fill" ) )
     {
-      hasRendererStyle = parseFillLayer( jsonLayer, rendererStyle, context );
+      hasRendererStyle = parseFillLayer( jsonLayer, rendererStyle, *context );
     }
     else if ( layerType == QLatin1String( "line" ) )
     {
-      hasRendererStyle = parseLineLayer( jsonLayer, rendererStyle, context );
+      hasRendererStyle = parseLineLayer( jsonLayer, rendererStyle, *context );
     }
     else if ( layerType == QLatin1String( "symbol" ) )
     {
-      parseSymbolLayer( jsonLayer, rendererStyle, hasRendererStyle, labelingStyle, hasLabelingStyle, context );
+      parseSymbolLayer( jsonLayer, rendererStyle, hasRendererStyle, labelingStyle, hasLabelingStyle, *context );
     }
     else
     {
@@ -137,8 +140,8 @@ void QgsMapBoxGlStyleConverter::parseLayers( const QVariantList &layers )
       labelingStyles.append( labelingStyle );
     }
 
-    mWarnings.append( context.warnings() );
+    mWarnings.append( context->warnings() );
-    context.clearWarnings();
+    context->clearWarnings();
   }
 
   mRenderer = qgis::make_unique< QgsVectorTileBasicRenderer >();
@@ -275,8 +278,8 @@ bool QgsMapBoxGlStyleConverter::parseFillLayer( const QVariantMap &jsonLayer, Qg
   QgsSimpleFillSymbolLayer *fillSymbol = dynamic_cast< QgsSimpleFillSymbolLayer * >( symbol->symbolLayer( 0 ) );
 
   // set render units
-  symbol->setOutputUnit( QgsUnitTypes::RenderPixels );
+  symbol->setOutputUnit( context.targetUnit() );
-  fillSymbol->setOutputUnit( QgsUnitTypes::RenderPixels );
+  fillSymbol->setOutputUnit( context.targetUnit() );
 
   if ( jsonPaint.contains( QStringLiteral( "fill-pattern" ) ) )
   {
@@ -387,17 +390,17 @@ bool QgsMapBoxGlStyleConverter::parseLineLayer( const QVariantMap &jsonLayer, Qg
     {
       case QVariant::Int:
       case QVariant::Double:
-        lineWidth = jsonLineWidth.toDouble();
+        lineWidth = jsonLineWidth.toDouble() * context.pixelSizeConversionFactor();
         break;
 
       case QVariant::Map:
         lineWidth = -1;
-        ddProperties.setProperty( QgsSymbolLayer::PropertyStrokeWidth, parseInterpolateByZoom( jsonLineWidth.toMap(), context, PIXEL_RATIO ) );
+        ddProperties.setProperty( QgsSymbolLayer::PropertyStrokeWidth, parseInterpolateByZoom( jsonLineWidth.toMap(), context, context.pixelSizeConversionFactor() ) );
         break;
 
       case QVariant::List:
       case QVariant::StringList:
-        ddProperties.setProperty( QgsSymbolLayer::PropertyStrokeWidth, parseInterpolateListByZoom( jsonLineWidth.toList(), PropertyType::Numeric, context, PIXEL_RATIO ) );
+        ddProperties.setProperty( QgsSymbolLayer::PropertyStrokeWidth, parseInterpolateListByZoom( jsonLineWidth.toList(), PropertyType::Numeric, context, context.pixelSizeConversionFactor() ) );
         break;
 
       default:
@@ -460,7 +463,7 @@ bool QgsMapBoxGlStyleConverter::parseLineLayer( const QVariantMap &jsonLayer, Qg
         const QVariantList dashSource = jsonLineDashArray.toMap().value( QStringLiteral( "stops" ) ).toList().last().toList().value( 1 ).toList();
         for ( const QVariant &v : dashSource )
         {
-          dashVector << v.toDouble() * PIXEL_RATIO;
+          dashVector << v.toDouble() * context.pixelSizeConversionFactor();
         }
         break;
       }
@@ -471,7 +474,7 @@ bool QgsMapBoxGlStyleConverter::parseLineLayer( const QVariantMap &jsonLayer, Qg
         const QVariantList dashSource = jsonLineDashArray.toList();
         for ( const QVariant &v : dashSource )
         {
-          dashVector << v.toDouble() * PIXEL_RATIO;
+          dashVector << v.toDouble() * context.pixelSizeConversionFactor();
         }
         break;
       }
@@ -501,8 +504,8 @@ bool QgsMapBoxGlStyleConverter::parseLineLayer( const QVariantMap &jsonLayer, Qg
   QgsSimpleLineSymbolLayer *lineSymbol = dynamic_cast< QgsSimpleLineSymbolLayer * >( symbol->symbolLayer( 0 ) );
 
   // set render units
-  symbol->setOutputUnit( QgsUnitTypes::RenderPixels );
+  symbol->setOutputUnit( context.targetUnit() );
-  lineSymbol->setOutputUnit( QgsUnitTypes::RenderPixels );
+  lineSymbol->setOutputUnit( context.targetUnit() );
   lineSymbol->setPenCapStyle( penCapStyle );
   lineSymbol->setPenJoinStyle( penJoinStyle );
   lineSymbol->setDataDefinedProperties( ddProperties );
@@ -517,7 +520,7 @@ bool QgsMapBoxGlStyleConverter::parseLineLayer( const QVariantMap &jsonLayer, Qg
   }
   if ( lineWidth != -1 )
   {
-    lineSymbol->setWidth( lineWidth * PIXEL_RATIO );
+    lineSymbol->setWidth( lineWidth );
   }
   if ( !dashVector.empty() )
   {
@@ -560,18 +563,18 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
     {
       case QVariant::Int:
       case QVariant::Double:
-        textSize = jsonTextSize.toDouble();
+        textSize = jsonTextSize.toDouble() * context.pixelSizeConversionFactor();
         break;
 
       case QVariant::Map:
         textSize = -1;
-        ddLabelProperties.setProperty( QgsPalLayerSettings::Size, parseInterpolateByZoom( jsonTextSize.toMap(), context ) );
+        ddLabelProperties.setProperty( QgsPalLayerSettings::Size, parseInterpolateByZoom( jsonTextSize.toMap(), context, context.pixelSizeConversionFactor() ) );
         break;
 
       case QVariant::List:
       case QVariant::StringList:
         textSize = -1;
-        ddLabelProperties.setProperty( QgsPalLayerSettings::Size, parseInterpolateListByZoom( jsonTextSize.toList(), PropertyType::Numeric, context ) );
+        ddLabelProperties.setProperty( QgsPalLayerSettings::Size, parseInterpolateListByZoom( jsonTextSize.toList(), PropertyType::Numeric, context, context.pixelSizeConversionFactor() ) );
         break;
 
       default:
@@ -690,18 +693,18 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
     {
       case QVariant::Int:
       case QVariant::Double:
-        bufferSize = jsonHaloWidth.toDouble();
+        bufferSize = jsonHaloWidth.toDouble() * context.pixelSizeConversionFactor();
         break;
 
       case QVariant::Map:
         bufferSize = 1;
-        ddLabelProperties.setProperty( QgsPalLayerSettings::BufferSize, parseInterpolateByZoom( jsonHaloWidth.toMap(), context ) );
+        ddLabelProperties.setProperty( QgsPalLayerSettings::BufferSize, parseInterpolateByZoom( jsonHaloWidth.toMap(), context, context.pixelSizeConversionFactor() ) );
         break;
 
       case QVariant::List:
       case QVariant::StringList:
         bufferSize = 1;
-        ddLabelProperties.setProperty( QgsPalLayerSettings::BufferSize, parseInterpolateListByZoom( jsonHaloWidth.toList(), PropertyType::Numeric, context ) );
+        ddLabelProperties.setProperty( QgsPalLayerSettings::BufferSize, parseInterpolateListByZoom( jsonHaloWidth.toList(), PropertyType::Numeric, context, context.pixelSizeConversionFactor() ) );
         break;
 
       default:
@@ -719,7 +722,7 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
       case QVariant::Int:
       case QVariant::Double:
       {
-        haloBlurSize = jsonTextHaloBlur.toDouble();
+        haloBlurSize = jsonTextHaloBlur.toDouble() * context.pixelSizeConversionFactor();
         break;
       }
 
@@ -730,7 +733,7 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
   }
 
   QgsTextFormat format;
-  format.setSizeUnit( QgsUnitTypes::RenderPixels );
+  format.setSizeUnit( context.targetUnit() );
   if ( textColor.isValid() )
     format.setColor( textColor );
   if ( textSize >= 0 )
@@ -741,8 +744,8 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
   if ( bufferSize > 0 )
   {
     format.buffer().setEnabled( true );
-    format.buffer().setSize( bufferSize * PIXEL_RATIO );
+    format.buffer().setSize( bufferSize );
-    format.buffer().setSizeUnit( QgsUnitTypes::RenderPixels );
+    format.buffer().setSizeUnit( context.targetUnit() );
     format.buffer().setColor( bufferColor );
 
     if ( haloBlurSize > 0 )
@@ -750,7 +753,7 @@ void QgsMapBoxGlStyleConverter::parseSymbolLayer( const QVariantMap &jsonLayer,
       QgsEffectStack *stack = new QgsEffectStack();
       QgsBlurEffect *blur = new QgsBlurEffect() ;
       blur->setEnabled( true );
-      blur->setBlurUnit( QgsUnitTypes::RenderPixels );
+      blur->setBlurUnit( context.targetUnit() );
       blur->setBlurLevel( haloBlurSize );
       blur->setBlurMethod( QgsBlurEffect::StackBlur );
       stack->appendEffect( blur );
@@ -1470,3 +1473,23 @@ void QgsMapBoxGlStyleConversionContext::pushWarning( const QString &warning )
   QgsDebugMsg( warning );
   mWarnings << warning;
 }
+
+QgsUnitTypes::RenderUnit QgsMapBoxGlStyleConversionContext::targetUnit() const
+{
+  return mTargetUnit;
+}
+
+void QgsMapBoxGlStyleConversionContext::setTargetUnit( QgsUnitTypes::RenderUnit targetUnit )
+{
+  mTargetUnit = targetUnit;
+}
+
+double QgsMapBoxGlStyleConversionContext::pixelSizeConversionFactor() const
+{
+  return mSizeConversionFactor;
+}
+
+void QgsMapBoxGlStyleConversionContext::setPixelSizeConversionFactor( double sizeConversionFactor )
+{
+  mSizeConversionFactor = sizeConversionFactor;
+}

src/core/vectortile/qgsmapboxglstyleconverter.h

@@ -52,9 +52,58 @@ class CORE_EXPORT QgsMapBoxGlStyleConversionContext
      */
     void clearWarnings() { mWarnings.clear(); }
 
+    /**
+     * Returns the target unit type.
+     *
+     * By default this is QgsUnitTypes::RenderPixels in order to exactly match the original
+     * style rendering. But rendering in pixels can cause issues on hidpi displays or with print
+     * layouts, so setting a target unit of QgsUnitTypes::Millimeters or another real-world unit
+     * type is often more appropriate.
+     *
+     * \see setTargetUnit()
+     */
+    QgsUnitTypes::RenderUnit targetUnit() const;
+
+    /**
+     * Sets the target unit type.
+     *
+     * By default this is QgsUnitTypes::RenderPixels in order to exactly match the original
+     * style rendering. But rendering in pixels can cause issues on hidpi displays or with print
+     * layouts, so setting a target unit of QgsUnitTypes::Millimeters or another real-world unit
+     * type is often more appropriate.
+     *
+     * If setting to a non-pixel unit, be sure to call setPixelSizeConversionFactor() in order
+     * to setup an appropriate pixel-to-unit conversion factor to scale converted sizes
+     * using. E.g. if the target unit is millimeters, the size conversion factor should be
+     * set to a pixel-to-millimeter value.
+     *
+     * \see targetUnit()
+     */
+    void setTargetUnit( QgsUnitTypes::RenderUnit targetUnit );
+
+    /**
+     * Returns the pixel size conversion factor, used to scale the original pixel sizes
+     * when converting styles.
+     *
+     * \see setSizeConversionFactor()
+     */
+    double pixelSizeConversionFactor() const;
+
+    /**
+     * Sets the pixel size conversion factor, used to scale the original pixel sizes
+     * when converting styles.
+     *
+     * \see pixelSizeConversionFactor()
+     */
+    void setPixelSizeConversionFactor( double sizeConversionFactor );
+
   private:
 
     QStringList mWarnings;
+
+    QgsUnitTypes::RenderUnit mTargetUnit = QgsUnitTypes::RenderPixels;
+
+    double mSizeConversionFactor = 1.0;
 };
 
 /**
@@ -99,8 +148,10 @@ class CORE_EXPORT QgsMapBoxGlStyleConverter
      *
      * After conversion, the resultant labeling and style rules can be retrieved by calling
      * renderer() or labeling() respectively.
+     *
+     * The optional \a context argument can be set to use a specific context during the conversion.
      */
-    Result convert( const QVariantMap &style );
+    Result convert( const QVariantMap &style, QgsMapBoxGlStyleConversionContext *context = nullptr );
 
     /**
      * Converts a JSON \a style string, and returns the resultant status of the conversion.
@@ -110,8 +161,10 @@ class CORE_EXPORT QgsMapBoxGlStyleConverter
      *
      * After conversion, the resultant labeling and style rules can be retrieved by calling
      * renderer() or labeling() respectively.
+     *
+     * The optional \a context argument can be set to use a specific context during the conversion.
      */
-    Result convert( const QString &style );
+    Result convert( const QString &style, QgsMapBoxGlStyleConversionContext *context = nullptr );
 
     /**
      * Returns a descriptive error message if an error was encountered during the style conversion,
@@ -158,7 +211,7 @@ class CORE_EXPORT QgsMapBoxGlStyleConverter
      * Parse list of \a layers from JSON.
      * \warning This is private API only, and may change in future QGIS versions
      */
-    void parseLayers( const QVariantList &layers );
+    void parseLayers( const QVariantList &layers, QgsMapBoxGlStyleConversionContext *context = nullptr );
 
     /**
      * Parses a fill layer.