Merge pull request #43121 from mhugent/vector_label_legend

Vector label legend
qgis · May 17, 2021 · 5585622 · 5585622
2 parents eaf7080 + def886d
commit 5585622
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Showing 15 changed files with 547 additions and 103 deletions.
diff --git a/python/core/auto_generated/labeling/qgspallabeling.sip.in b/python/core/auto_generated/labeling/qgspallabeling.sip.in
@@ -482,6 +482,20 @@ Sets the polygon placement ``flags``, which dictate how polygon labels can be pl
 
     QgsWkbTypes::GeometryType layerType;
 
+    void setLegendString( const QString &legendString );
+%Docstring
+setLegendString
+
+:param legendString: the string to show in the legend and preview
+%End
+
+    QString legendString() const;
+%Docstring
+legendString
+
+:return: the string to show in the legend and in the preview icon
+%End
+
     void calculateLabelSize( const QFontMetricsF *fm, const QString &text, double &labelX, double &labelY, const QgsFeature *f = 0, QgsRenderContext *context = 0, double *rotatedLabelX /Out/ = 0, double *rotatedLabelY /Out/ = 0 );
 %Docstring
 Calculates the space required to render the provided ``text`` in map units.

diff --git a/python/core/auto_generated/layertree/qgslayertreemodellegendnode.sip.in b/python/core/auto_generated/layertree/qgslayertreemodellegendnode.sip.in
@@ -665,6 +665,65 @@ Construct the node using :py:class:`QgsDataDefinedSizeLegend` as definition of t
 
 };
 
+class QgsVectorLabelLegendNode : QgsLayerTreeModelLegendNode
+{
+%Docstring(signature="appended")
+Produces legend node for a labeling text symbol
+
+.. versionadded:: 3.20
+%End
+
+%TypeHeaderCode
+#include "qgslayertreemodellegendnode.h"
+%End
+  public:
+
+    QgsVectorLabelLegendNode( QgsLayerTreeLayer *nodeLayer, const QgsPalLayerSettings &labelSettings, QObject *parent = 0 );
+%Docstring
+QgsVectorLabelLegendNode
+
+:param nodeLayer: the parent node
+:param labelSettings: setting of the label class
+:param parent: the parent object
+%End
+    ~QgsVectorLabelLegendNode();
+
+    virtual QVariant data( int role ) const;
+
+%Docstring
+data Returns data associated with the item
+
+:param role: the data role
+
+:return: variant containing the data for the role
+%End
+
+    virtual QSizeF drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const;
+
+%Docstring
+drawSymbol
+
+:param settings: the legend settings
+:param ctx: context for the item
+:param itemHeight: the height of the item
+
+:return: size of the item
+%End
+
+    virtual QJsonObject exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const;
+
+%Docstring
+exportSymbolToJson
+
+:param settings: the legend settings
+:param context: the item context
+
+:return: the json object
+%End
+
+};
+
+
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

diff --git a/python/core/auto_generated/qgsmaplayerlegend.sip.in b/python/core/auto_generated/qgsmaplayerlegend.sip.in
@@ -259,6 +259,22 @@ may have extra text rendered on top. The content of labels and their style is co
 by :py:func:`~QgsDefaultVectorLayerLegend.textOnSymbolContent` and :py:func:`~QgsDefaultVectorLayerLegend.textOnSymbolTextFormat`.
 
 .. versionadded:: 3.2
+%End
+
+    bool showLabelLegend() const;
+%Docstring
+Returns whether the legend for the labeling is shown
+
+.. versionadded:: 3.20
+%End
+
+    void setShowLabelLegend( bool enabled );
+%Docstring
+Sets if a legend for the labeling should be shown
+
+:param enabled: true to show label legend entries
+
+.. versionadded:: 3.20
 %End
 
     QgsTextFormat textOnSymbolTextFormat() const;

diff --git a/src/core/labeling/qgspallabeling.cpp b/src/core/labeling/qgspallabeling.cpp
@@ -366,6 +366,8 @@ QgsPalLayerSettings &QgsPalLayerSettings::operator=( const QgsPalLayerSettings &
   geometryGeneratorType = s.geometryGeneratorType;
   layerType = s.layerType;
 
+  mLegendString = s.mLegendString;
+
   return *this;
 }
 
@@ -928,6 +930,7 @@ void QgsPalLayerSettings::readXml( const QDomElement &elem, const QgsReadWriteCo
   Q_NOWARN_DEPRECATED_POP
   substitutions.readXml( textStyleElem.firstChildElement( QStringLiteral( "substitutions" ) ) );
   useSubstitutions = textStyleElem.attribute( QStringLiteral( "useSubstitutions" ) ).toInt();
+  mLegendString = textStyleElem.attribute( QStringLiteral( "legendString" ), QObject::tr( "Aa" ) );
 
   // text formatting
   QDomElement textFormatElem = elem.firstChildElement( QStringLiteral( "text-format" ) );
@@ -1167,6 +1170,7 @@ QDomElement QgsPalLayerSettings::writeXml( QDomDocument &doc, const QgsReadWrite
   substitutions.writeXml( replacementElem, doc );
   textStyleElem.appendChild( replacementElem );
   textStyleElem.setAttribute( QStringLiteral( "useSubstitutions" ), useSubstitutions );
+  textStyleElem.setAttribute( QStringLiteral( "legendString" ), mLegendString );
 
   // text formatting
   QDomElement textFormatElem = doc.createElement( QStringLiteral( "text-format" ) );
@@ -1341,7 +1345,7 @@ QPixmap QgsPalLayerSettings::labelSettingsPreviewPixmap( const QgsPalLayerSettin
   if ( tempFormat.background().enabled() )
     ytrans = std::max( ytrans, context.convertToPainterUnits( tempFormat.background().size().height(), tempFormat.background().sizeUnit(), tempFormat.background().sizeMapUnitScale() ) );
 
-  const QStringList text = QStringList() << ( previewText.isEmpty() ? QObject::tr( "Aa" ) : previewText );
+  const QStringList text = QStringList() << ( previewText.isEmpty() ? settings.legendString() : previewText );
   const double textHeight = QgsTextRenderer::textHeight( context, tempFormat, text, QgsTextRenderer::Rect );
   QRectF textRect = rect;
   textRect.setLeft( xtrans + padding );

diff --git a/src/core/labeling/qgspallabeling.h b/src/core/labeling/qgspallabeling.h
@@ -798,6 +798,18 @@ class CORE_EXPORT QgsPalLayerSettings
      */
     QgsWkbTypes::GeometryType layerType = QgsWkbTypes::UnknownGeometry;
 
+    /**
+     * \brief setLegendString
+     * \param legendString the string to show in the legend and preview
+     */
+    void setLegendString( const QString &legendString ) { mLegendString = legendString; }
+
+    /**
+     * \brief legendString
+     * \return the string to show in the legend and in the preview icon
+     */
+    QString legendString() const { return mLegendString; }
+
     /**
      * Calculates the space required to render the provided \a text in map units.
      * Results will be written to \a labelX and \a labelY.
@@ -1087,6 +1099,8 @@ class CORE_EXPORT QgsPalLayerSettings
 
     bool mRenderStarted = false;
 
+    QString mLegendString = QObject::tr( "Aa" );
+
     static void initPropertyDefinitions();
 };
 

diff --git a/src/core/layertree/qgslayertreemodellegendnode.cpp b/src/core/layertree/qgslayertreemodellegendnode.cpp
@@ -1434,3 +1434,93 @@ void QgsDataDefinedSizeLegendNode::cacheImage() const
   }
 }
 
+QgsVectorLabelLegendNode::QgsVectorLabelLegendNode( QgsLayerTreeLayer *nodeLayer, const QgsPalLayerSettings &labelSettings, QObject *parent ): QgsLayerTreeModelLegendNode( nodeLayer, parent ), mLabelSettings( labelSettings )
+{
+}
+
+QgsVectorLabelLegendNode::~QgsVectorLabelLegendNode()
+{
+}
+
+QVariant QgsVectorLabelLegendNode::data( int role ) const
+{
+  if ( role == Qt::DisplayRole )
+  {
+    return mUserLabel;
+  }
+  if ( role == Qt::DecorationRole )
+  {
+    const int iconSize = QgsLayerTreeModel::scaleIconSize( 16 );
+    return QgsPalLayerSettings::labelSettingsPreviewPixmap( mLabelSettings, QSize( iconSize, iconSize ), mLabelSettings.legendString() );
+  }
+  return QVariant();
+}
+
+QSizeF QgsVectorLabelLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const
+{
+  Q_UNUSED( itemHeight );
+  if ( !ctx )
+  {
+    return QSizeF( 0, 0 );
+  }
+
+  const QgsRenderContext *renderContext = ctx->context;
+  if ( renderContext )
+  {
+    return drawSymbol( settings, *renderContext, ctx->columnLeft, ctx->top );
+  }
+
+  return QSizeF( 0, 0 );
+}
+
+QSizeF QgsVectorLabelLegendNode::drawSymbol( const QgsLegendSettings &settings, const QgsRenderContext &renderContext, double xOffset, double yOffset ) const
+{
+  QStringList textLines( mLabelSettings.legendString() );
+  QgsTextFormat textFormat = mLabelSettings.format();
+  QgsRenderContext ctx( renderContext );
+  double textWidth, textHeight;
+  textWidthHeight( textWidth, textHeight, ctx, textFormat, textLines );
+  textWidth /= renderContext.scaleFactor();
+  textHeight /= renderContext.scaleFactor();
+  QPointF textPos( renderContext.scaleFactor() * ( xOffset + settings.symbolSize().width() / 2.0 - textWidth / 2.0 ), renderContext.scaleFactor() * ( yOffset + settings.symbolSize().height() / 2.0 + textHeight / 2.0 ) );
+
+  QgsScopedRenderContextScaleToPixels scopedScaleToPixels( ctx );
+  QgsTextRenderer::drawText( textPos, 0.0, QgsTextRenderer::AlignLeft, textLines, ctx, textFormat );
+
+  const double symbolWidth = std::max( textWidth, settings.symbolSize().width() );
+  const double symbolHeight = std::max( textHeight, settings.symbolSize().height() );
+  return QSizeF( symbolWidth, symbolHeight );
+}
+
+QJsonObject QgsVectorLabelLegendNode::exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const
+{
+  Q_UNUSED( settings );
+
+  const double mmToPixel = 96.0 / 25.4; //settings.dpi() is deprecated
+
+  const QStringList textLines( mLabelSettings.legendString() );
+  const QgsTextFormat textFormat = mLabelSettings.format();
+  QgsRenderContext ctx( context );
+  ctx.setScaleFactor( mmToPixel );
+
+  double textWidth, textHeight;
+  textWidthHeight( textWidth, textHeight, ctx, textFormat, textLines );
+  QPixmap previewPixmap = mLabelSettings.labelSettingsPreviewPixmap( mLabelSettings, QSize( textWidth, textHeight ), mLabelSettings.legendString() );
+
+  QByteArray byteArray;
+  QBuffer buffer( &byteArray );
+  previewPixmap.save( &buffer, "PNG" );
+  const QString base64 = QString::fromLatin1( byteArray.toBase64().data() );
+
+  QJsonObject json;
+  json[ QStringLiteral( "icon" ) ] = base64;
+  return json;
+}
+
+void QgsVectorLabelLegendNode::textWidthHeight( double &width, double &height, QgsRenderContext &ctx, const QgsTextFormat &textFormat, const QStringList &textLines ) const
+{
+  QFontMetricsF fm = QgsTextRenderer::fontMetrics( ctx, textFormat );
+  height = QgsTextRenderer::textHeight( ctx, textFormat, 'A', true );
+  width = QgsTextRenderer::textWidth( ctx, textFormat, textLines, &fm );
+}
+
diff --git a/src/core/layertree/qgslayertreemodellegendnode.h b/src/core/layertree/qgslayertreemodellegendnode.h
@@ -27,6 +27,7 @@
 
 #include "qgsexpressioncontext.h"
 #include "qgslegendpatchshape.h"
+#include "qgspallabeling.h"
 
 class QgsLayerTreeLayer;
 class QgsLayerTreeModel;
@@ -722,4 +723,53 @@ class CORE_EXPORT QgsDataDefinedSizeLegendNode : public QgsLayerTreeModelLegendN
     mutable QImage mImage;
 };
 
+/**
+ * \ingroup core
+ * \brief Produces legend node for a labeling text symbol
+ * \since QGIS 3.20
+ */
+class CORE_EXPORT QgsVectorLabelLegendNode : public QgsLayerTreeModelLegendNode
+{
+  public:
+
+    /**
+     * \brief QgsVectorLabelLegendNode
+     * \param nodeLayer the parent node
+     * \param labelSettings setting of the label class
+     * \param parent the parent object
+     */
+    QgsVectorLabelLegendNode( QgsLayerTreeLayer *nodeLayer, const QgsPalLayerSettings &labelSettings, QObject *parent = nullptr );
+    ~QgsVectorLabelLegendNode() override;
+
+    /**
+     * \brief data Returns data associated with the item
+     * \param role the data role
+     * \returns variant containing the data for the role
+     */
+    QVariant data( int role ) const override;
+
+    /**
+     * \brief drawSymbol
+     * \param settings the legend settings
+     * \param ctx context for the item
+     * \param itemHeight the height of the item
+     * \returns size of the item
+     */
+    QSizeF drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const override;
+
+    /**
+     * \brief exportSymbolToJson
+     * \param settings the legend settings
+     * \param context the item context
+     * \returns the json object
+     */
+    QJsonObject exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const override;
+
+  private:
+    QgsPalLayerSettings mLabelSettings;
+    QSizeF drawSymbol( const QgsLegendSettings &settings, const QgsRenderContext &renderContext, double xOffset = 0.0, double yOffset = 0.0 ) const;
+    void textWidthHeight( double &width, double &height, QgsRenderContext &ctx, const QgsTextFormat &textFormat, const QStringList &textLines ) const;
+};
+
+
 #endif // QGSLAYERTREEMODELLEGENDNODE_H
diff --git a/src/core/qgsmaplayerlegend.cpp b/src/core/qgsmaplayerlegend.cpp
@@ -29,6 +29,8 @@
 #include "qgspointcloudrenderer.h"
 #include "qgsrasterrenderer.h"
 #include "qgscolorramplegendnode.h"
+#include "qgsvectorlayerlabeling.h"
+#include "qgsrulebasedlabeling.h"
 
 QgsMapLayerLegend::QgsMapLayerLegend( QObject *parent )
   : QObject( parent )
@@ -400,6 +402,32 @@ QList<QgsLayerTreeModelLegendNode *> QgsDefaultVectorLayerLegend::createLayerTre
     }
   }
 
+  if ( mLayer->labelsEnabled() && mShowLabelLegend )
+  {
+    const QgsAbstractVectorLayerLabeling *labeling = mLayer->labeling();
+    if ( labeling )
+    {
+      QStringList pList = labeling->subProviders();
+      for ( int i = 0; i < pList.size(); ++i )
+      {
+        const QgsPalLayerSettings s = labeling->settings( pList.at( i ) );
+        QString description;
+        const QgsRuleBasedLabeling *ruleBasedLabeling = dynamic_cast<const QgsRuleBasedLabeling *>( labeling );
+        if ( ruleBasedLabeling && ruleBasedLabeling->rootRule() )
+        {
+          const QgsRuleBasedLabeling::Rule *rule = ruleBasedLabeling->rootRule()->findRuleByKey( pList.at( i ) );
+          if ( rule )
+          {
+            description = rule->description();
+          }
+        }
+        QgsVectorLabelLegendNode *node = new QgsVectorLabelLegendNode( nodeLayer, s );
+        node->setUserLabel( description );
+        nodes.append( node );
+      }
+    }
+  }
+
 
   return nodes;
 }
@@ -410,6 +438,8 @@ void QgsDefaultVectorLayerLegend::readXml( const QDomElement &elem, const QgsRea
   mTextOnSymbolTextFormat = QgsTextFormat();
   mTextOnSymbolContent.clear();
 
+  mShowLabelLegend = elem.attribute( QStringLiteral( "showLabelLegend" ), QStringLiteral( "0" ) ).compare( QStringLiteral( "1" ), Qt::CaseInsensitive ) == 0;
+
   QDomElement tosElem = elem.firstChildElement( QStringLiteral( "text-on-symbol" ) );
   if ( !tosElem.isNull() )
   {
@@ -430,6 +460,7 @@ QDomElement QgsDefaultVectorLayerLegend::writeXml( QDomDocument &doc, const QgsR
 {
   QDomElement elem = doc.createElement( QStringLiteral( "legend" ) );
   elem.setAttribute( QStringLiteral( "type" ), QStringLiteral( "default-vector" ) );
+  elem.setAttribute( QStringLiteral( "showLabelLegend" ), mShowLabelLegend );
 
   if ( mTextOnSymbolEnabled )
   {